# Methods of Analy s is by t he U.S. Geological Survey

National W a ter Quality Laboratory

— Determination of

Moderate-Use Pesticides and Selected Degradates in

W a ter by C-18 Solid-Phase Extraction and Gas

Chromatography /Mass Spectrometry

W a ter-Resources Inv e stigations Report 01-4098



# U.S. Department of the Interior

U.S. Geological Survey

# Methods of Analy s is by t he U.S. Geological Survey

National W a ter Quality Laboratory

— Determination of

Moderate-Use Pesticides and Selected Degradates in

W a ter by C-18 Solid-Phase Extraction and Gas

Chromatography /Mass Spectrometry

By Mark W

. Sandstrom, Max E. Stroppel, W illiam T. Foreman,

and Michael P. Schroeder

_______________________________________________________

U.S. GEOLOGICAL SURVEY

W a ter-Resources Inv e stigations Report 01-4098

U.S. Geological Surv ey Method O-2002-01

Laboratory Methods (Schedules) 2002 and 2011

D env er , C o l o r ado

2001

## U. S. Depar t ment of the I n ter i or

Gale A

. Norton, Secretary

U. S. Geol ogi cal Sur v ey

Charles G. Gr oat, Di r ector

T he us e of tr ade, pr oduc t, or f i r m nam es in this r epor t is f o r des c r iptive

pur pos es only and does not im ply endor s e m ent by the U.S. G o ver n m ent.

F o r additional inf o r m ation w r ite to: Copies of this r epor t c an be pur c has ed f r om :

Chief

, National W a ter Q uality Labor ator y U.S. G eologic a l Sur v ey

U.S. G eologic a l Sur v ey Br anc h of Inf o r m ation Ser v ic es

Box 25046, Mail Stop 407 Box 25286

F eder al Center F eder al Center

Denver , CO 80225- 0046 Denver , CO 80225- 0286

# CONTENTS

Abst ract 1

I n troduction 1

I n itial method development 3

Analy tical method 6

1. Scope and application 6

2. Summary of method 13

3. I n t e rferences 14

4. Apparatus and instrumentation 14

5. Reag ents and consumable materials 16

6. Sampling methods, sample-c ollection equipment, and

cl eani n g procedures 16

7. Standards 18

8. Ga s c h r o ma tog r a ph/ma ss spe c t r o me te r pe r f o r

m a n c e 19

9. Calibration 22

10. Procedure 23

11. Calculation of results 29

12. Reporting of results 31

F i nal method validation 32

Other considerations 61

Conclusions 63

R e ferences ci t e d 63

Supplement A—Automated solid-phase ex traction procedure using

Aut o Trace workst at i on 65

Supplement B

— I n structions for on-site processing using solid-phase

ex t r act i on (S P E ) 67

FIGU R ES

1. Selected ion chromatog r am of pest i c i d es and deg r adat es i n a

0.625-nanog ram-per-microliter (ng / μL ) standard 21

2. B i a s a nd va r i a b ility da ta f

r o m r e a g e n t- wa te r

- s e t sa mple s

fortified with analy t es at low (0.1 mic rog r am per liter) concentrations and

prepared during March throug h December, 1999 60

TA B L ES

1. Ana l y t e s tha t we r e initia lly c onside r e d or te ste d but subse que ntly

e limina t e d f

r o m c o mple te va lida tion e x pe r ime nts be c a use of

problems with ordering , analy s is, or recovery 4

2. Pesticides and deg r adat es included in new method 8

3. Relation of pesticide deg r adates included in new method to parent

pesticides in U.S. Geolog ical Survey methods 2001, 2050, and 2002 11

4. Volumes of primary combined for tification, internal, and surrog a te

st andards needed t o prepare sug g e st ed concentrations of calibration standards 20

Contents iii

### 5. Retention time, qua ntitation ion, and confirmation ions for analy t es,

surrog a tes, and internal standards, and selected ion-monitoring g r oup

and internal standard for analy t es and surrog a tes 24

6. B i a s a nd va r i a b ility da ta f

r o m e i g h t r e a g e n t- wa te r sa mple s f o r tif ie d

with parent pesticide analy t es at hig h (1.0 microg r am per liter)

and low (0.1 microg r am pe r liter) concentrations 33

7. B i a s a nd va r i a b ility da ta f

r o m e i g h t r e a g e n t- wa te r sa mple s f o r tif ie d

with deg r adates at hig h (1.0 microg r am per liter) and low

(0.1 microg r am per liter) concentrations 36

8. B i a s a nd va r i a b ility da ta f

r o m e i g h t sur f a c e

- w a t e r sa mple s f o r tif ie d

with parent pesticides and deg r adat es at hig h (1.0 microg r am per liter)

and low (0.1 microg r am pe r liter) concentrations 38

9. B i as and variability data from ei g h t g r ound-water samp les fortified

with parent pesticides and deg r adat es at hig h (1.0 microg r am per liter)

and low (0.1 microg r am pe r liter) concentrations 41

10. Method detection limits and preliminary laborat ory reporting levels

f o r

pe stic ide s a nd pe stic ide de g r a d a t e s c a l c u la te d f r o m de te r mina tion

of

the a n a l y t e s in e i g h t r e a g e n t- wa te r sa mple s f o r tif ie d a t c onc e n tr a tions

from 0.015 to 0.1 microg r am per liter 45

11. Number of replicates required to determine estimate d holding time of

parent pesticides in water and on solid-pha se

- e x t r a c tion c o lumns 50

12. Number of replicates required to determine estimate d holding time of

deg r adates in water and on so lid- pha se

- e x t r a c tion c o lumns 51

13. Statistical data used to determine estimated holding time of parent pesticides

on dr y

solid- pha se

- e x t r a c tion c o lumns ma inta ine d a t 25 de g r e e s Ce lsius 52

14. Statistical data used to determine estimated holdi ng time of deg r adates

on solid- pha se

- e x t r a c tion c o lumns ma inta ine d a t 25 de g r e e s Ce lsius 53

15. Statistical data used to determine estimated hol ding time of parent

pe stic ide s in pe stic ide

- g r a d e wa te r ma inta ine d a t 4 de g r e e s Ce lsius 56

16. Statistical data used to determine estimated holdi ng time of deg r adates

in pe stic ide

- g r a d e wa te r ma inta ine d a t 4 de g r e e s Ce lsius 57

17. B i a s a nd va r i a b ility da ta f

r o m r e a g e n t- wa te r

- s e t sa mple s f o r tif ie d with

analy t es at low (0.1 microg r am per liter) concentrations

and analy z ed during March throug h December, 1999 58

18. Analy t es qualified as estimated concen tration because of larg e bias and

va r i a b ility r e sults of f

o r tif ie d r e a g e n t- wa te r

- s e t sa mple s ( t a b le 17) or shor t

holding -time results (tables 13–16) 62

19. Equipment and supplies required for broad spectrum pesticide analy s is

(methods 2010 and 2011) by on-s ite solid-phase ex traction 69

Contents iv

### CONVERSION FA CTORS

Mu ltip ly B y T o o b t a i n

Le ngt h

centim eter (cm ) 3.94 x 10 -1 

### inch

m i crom eter (μm ) 3.94 x 10 -5 

### inch

m illim eter (m m ) 3.94 x 10 -2 

### inch

m e ter (m ) 3.281 foot

Mass

g r am (g ) 3.53 x 10 -2 

### ounce

k ilog r am (k g ) 2.205 pound

mi c r o g r a m ( μ g ) 3.53 x 10 -8 

### ounce

m illig ram (m g ) 3.53 x 10 -5 

### ounce

nanog ram (ng ) 3.53 x 10 -1 1 

### ounce

Vol u m e liter (L ) 2.64 x 10 -1 

### g a llon

liter (L) 33.81 ounce, fliud

m i croliter (μL ) 2.64 x 10 -7 

### g a llon

m illiliter (m L ) 2.64 x 10 -4 

### g a llon

m illiliter (m L ) 1 cubic centim eter

P ressure

k ilopascal (k Pa) 1.45 x 10 -1 

### pounds per square inch

A rea hectares (ha) (or) hectom eter 2 

### (hm 2 

### ) 2

. 4 7 1 a c r e s

Concentration,

in w a ter

nanog ram s per liter (ng / L ) 1 parts per trillion (ppt)

m i crog ram s per liter (μg / L) 1 parts per billion (ppb)

m illig ram s per liter (m g / L ) 1 parts per m illion (ppm )



### De g r e e Ce lsius ( o C) may be converted to deg r ee F a hrenheit ( o F ) by using the following

equation:

o F = 9/5 ( o C) + 32.

Contents v

### A CRONYMS A ND A BBRE V I A T IONS

A ampere

cm/sec centimeter per second

dc direct current

μg /L mic r o g r a m pe r lite r

mg /L millig r a m pe r lite r

min minute

mL /min millilite r pe r minute

ng /L na nog r a m pe r lite r

ng /μL na nog r a m pe r mic r o lite r

lb/in 2 pound per square inch

V volt

± plus or minus

< le ss tha n

C-18 octadecy l

CCV continuing calibration verification

ETF E ethy lenetetrafluoroethy l ene

GC g a s c h r o ma tog r a phy

GC/MS g a s c h r o ma tog r a ph/ma ss spe c t r o me te r

GCC g l a ss bottle , a m be r

HP L C hi g h -perform ance liquid chromatog r aphy

I D i n si de di am et er

I S internal standard

L R L laboratory reporting level

L T –MDL long -term me thod detection level

MDL method detection limit

MS mass spectrometry

NAWQA Na tiona l Wa te r

- Q ua lity Asse ssme n t pr og r a m

NWI S Na tiona l Wa te r I n f o r

m a tion Sy ste m

NWQL Na tiona l Wa te r Qua lity L a bor a t or y

OD outside diameter

PAH poly c y c lic aromatic hy drocarbon

PF A perfluoralkox y

PF TB A perfluorotributy l amine

L R L laboratory reporting level

SI M selected-ion monitoring

SPE solid- pha se e x tr a c tion

USEPA U.S. Environmental Protection Ag ency

US GS U.S

. Geolog ical S u rvey

Contents vi

### GLOSSA RY

Analyte – The pest i c i d e or pest i c i d e deg r adat e det e rm i n ed i n an anal y s i s

.

Con t i n u i n g cal i b rati on veri f i cati on (CCV) – A calibration st andard that contains

method analy t es that is used to measure a nd control the bias of the ex isting calibration

curve for t h ese anal y t es. The C C V i s an i n st rumental standard only and is not processed

throug h preparative steps of the method.

F o rti f i e d reagen t-w ater-set sam p l e – A qua lity

- c ontr o l sa mple pr e p a r e d by

adding a known amount of analy t es to a reag en t-water sample and an aly z ed with each set

of environmental sample s (usually 10). Also known as a " s et spike."

In tern al stan d a rd (I S) – An analy t e not ex pected to be found in any environmental

sample that is added to ever y

sample ex tract in a known amount . The internal standard is

used to measure the relative GC/MS responses of other analy t es and surrog a tes in each

sa mple

.

L a b o ratory rep orti n g l e vel ( L RL ) – The c onc e n tr a tion whe r e the f a lse

- positive

e r

r o r is minimize d to no mor e tha n 1 pe r c e n t a nd the f a lse

- ne g a tive e r r o r is minimize d to

no mor e tha n 1 pe r c e n t. The L R L is c a l c u la te d a s 2 time s the MDL

. An a n a l y t e

de te r mine d to be not ide n tif ie d, confirmed, or measured in a sample is reported as <L RL

.

M e t hod de t e c t ion lim it (MDL ) – The m i n i m u m concent r at i on of an anal y t e t h at

can be measured and reported wi t h 99-percent confi d ence t h at t h e anal y t e concent r at i on

is g r e a t e r tha n ze r o. At this c onc e n tr a tion the f a lse positive e r r o r is minimize d to no

more than 1-percent probability (U.S. Environmental Protection Ag ency , 1997).

P r oc e dur al int e r n al st andar d quant it at ion – A quantitation method where the

inte r n a l sta nda r d is a dde d to the sa mple e x tr act prior to evaporati on and transfer-to-vial

sample processing steps. These final steps in t h e sam p l e -ex t ract processi ng are i n cl uded

in the quantitation. Use of the procedural internal-standard quan titation compensates for

any bi as i n t h e ex t r act evaporat i on and t r ansf er-to-vial sample processing steps, but not

the solid-phase ex traction and eluti on steps of the analy tical method.

Surrogate – An analy t e not ex pected to be f ound in any environmental sample that

is added to every sample in a known amount pr ior to sample processing . The surrog a te is

used to monitor method performance for each sample.

Contents v i i

# Methods of Analy s is by the U. S. Geological Survey National

Water Quality Laboratory

— Determination of Moderate-Use

Pesticides and Selected Degradates in Water by C-18 Solid-Phase

Extraction and Gas Chromatography /Mass Spectrometry

By Mark W

. Sandstrom , Max E. Stroppel, W illiam T

. Forem an,

and M i chael P. Schr oeder

U.S. Geological Surv ey Method O-2002-01

Laboratory Methods (Schedules) 2002 and 2011

A b st ract

A method for the isolation and analy s is

of 21 parent pesticid es and 20 pesticide

de g r a d a t e s in na tur a l- wa te r sa mple s is

de sc r i be d. Wa te r sa mple s a r e f ilte r e d to

remove suspended partic ula t e ma tte r a nd the n

are pumped throug h disposable solid-phaseex t r act i on col u m n s t h at cont ai n oct a decy l

bonded porous silica to ex tract the analy t es.

The columns are dried by using nitrog en g a s,

and adsorbed anal y t es are el ut ed wi t h et hy l

acet at e. Ex t r act ed anal y t es are det e rm i n ed by

c a p illa r y

- c olumn g a s c h r o ma tog r a phy /

ma ss spe c t r o me tr y

with se le c t e d

- i on

monitoring of three characteristic ions. The

upper concentration limit is 2 microg r ams per

lite r ( μ g / L ) f o r

most a n a l y t e s . Sing le

- ope r a tor

method detection limits in reag ent-water

samples rang e from 0.001 to 0.057 μg /L

. Validation data also are presented for 14

parent pesticides and 20 deg r adat es t h at were

de te r mine d to ha ve g r e a t e r bia s or va r i a b ility

,

or

shor te r holding time s tha n the othe r

compounds. The estimated max imum

holding time f o r

a n a l y t e s in pe stic ide

- g r a d e

water before ex traction was 4 day s . The

e s tima te d ma x imum holding time f o r

a n a l y t e s

after ex traction on the drysolid-phaseex traction columns was 7 day s . An optional

on-site ex traction procedure allows for

sa mple s to be c o lle c t ed and processed at

r e mote site s whe r e it is dif f i c u lt to ship

sa mple s to the la bor a t or y

within the r e c o mme nde d pr e

- e x tr a c tion holding time

. The method complements ex isting U.S.

Geolog ical Survey Method O-1126-95

(NW Q L Schedules 2001 and 2010) by using

i d ent i cal sam p l e preparat i on and com p arabl e

instrument analy tical conditions so that

sam p l e ex t r act s can be anal y z ed by ei t h er

method to ex pand the rang e of analy t es

de te r mine d f

r o m one wa te r sa mple

.

INTRODUCTION

Pe stic ide s a r e wide ly use d in the Unite d

States to increase production of ag ricultural

products by controlling weeds, insects, and

othe r pe sts in a wide va r i e t y of se tting s . Mor e

than 450 million kilog r ams of pesticides,

whic h inc l ude inse c tic ide s , he r b ic ide s , a nd

fung i c i d es, are used each y ear i n t h e Uni t e d

States. The fate of pes tic ide s a f te r a

pplic a tion

is important because of the pote n tia l a dve r s e

effect s of pest i c i d es on the environment and

human health, especially by movement into

the hy drolog ic sy stem. Small concentrations

of pesticides have been widespread in

surface- and g r ound-water samples for several

decades (B arbash and Resek, 1996; Gilliom

and others, 1999; L a rson and others, 1997;

L a rson and others, 1998).

Pe stic ide s , a s is the c a se f o r

most

org a nic compounds, also are transformed

aft e r rel ease t o t h e envi ronm ent

. Bot h

Introduction 1

### chemical and biolog ical processes mig ht

cause t h ese t r ansform a t i ons. The fat e of t h e

transformation products , referred to as

deg r adates, in surface and g r ound water is

frequently not known because deg r adates are

not commonly included in monitoring studies.

R ecent i n t e rest i n t h e presence and fat e of

de g r a d a t e s , howe v e r , ha s inc r e a s e d. L imite d

studies have indicated that when included in

survey s, deg r adat es are frequent l y det ect ed,

often at hig h er frequenc ies and concentrations

than many parent pestic ides. I n addition, an

understanding of the presence of deg r adates

can help provide an understanding of the

overall fate and beha vior processes of

pe stic ide s

.

There are t w o m a i n reasons why

deg r adates have not been included in previous

routine monitoring studies, even after the

recog n i t i on t h at t h ei r presence m i g ht be

relevant to evaluate environmental health.

Fi rst

, m a ny deg r adat es are m o re pol ar t h an

t h ei r parent pest i c i d es because t h e

transformation proce sses g e nerally add

ox y g enated or other polar functional g r oups

t o t h e m o l ecul e . These m o re pol ar deg r adat es

are t y pi cal l y m o re di ffi cul t t o anal y z e by

common g a s chromatog r aphy (GC) methods.

Second, and more importantly , analy tical

standards of many poten tial deg r adates have

not been widely available until recently , so

the y c ould not be inc l ude d in qua ntita tive

analy tical methods.

The U

. S. G e olog ic a l Sur v e y ( U SG S)

recently developed two analy tical methods for

the r outine de te r mina tion in wa te r of ma ny of

the pe stic ide s use d na tiona lly in g r e a t e s t

abundance (W erner and others, 1996; Z a ug g

and others, 1995). These methods were used

in the Na tiona l Wa te r

- Q ua lity Asse ssme n t

(NAW QA) prog ram as part of a study of the

presence and distribution of pesticides in

surface- and g r ound-water samples

nationwide (U.S. Geolog ical Survey , 2000).

Those methods included only three deg r adates, and did not include all of the top

120 pesticides used nationally , one of the

prog ram g o als.

The methods are referred to by

laboratory personnel and field teams

requesting analy tical services by National

Wa te r Qua lity L a bor a t or y

( N WQL )

schedules. The laboratory schedules are

ide n tif ie d f o r

the be ne f it of r e a d e r s of this

report. NW QL schedules 2001 and 2010

request analy s es of 47 pesticides that are

isola t e d f

r o m f ilte r e d wa te r by C- 18 solidphase ex traction (SPE ) and identified and

quantified by g a s c h r o ma tog r a phy /ma ss

spect rom e t r y

(GC / MS ) (Z aug g and ot hers,

1995). The pesticide acetoc hlor was added to

the methods in J une 1994 (L indley and others,

1996). NW QL schedules 2050 and 2051

request analy s es of 41 pesticides that are

isolated from filtered water by Carbopak-B

S P E and are i d ent i f i e d a nd quantified by hig h

performance liquid chromatog r aphy (HPL C)

with diode-array det ection (W erner and

others, 1996). B o th me thods have optional

procedures for on-s ite SPE. Schedules 2010

and 2051 request analy s es of pesticides in

sa mple s tha t we r e e x tr a c t e d f

r o m f ilte r e d

wa te r sa mple s on- site , whereas schedules

2001 and 2050 request analy s es for pesticides

tha t we r e e x tr a c t e d f

r o m wa te r sa mple s a t the

NW QL . F o r the purposes of this report,

schedules 2001 and 2010 w ill be referred to

as method 2001, and schedules 2050 and

2051 will be referred to as method 2050. The

new method presented in this report will be

referred to as method 2002, even thoug h field

te a m s will ne e d to r e que st e ithe r sc he dule s

2002 or 2011.

This report describes a method for

determining a broad rang e of pesticide

chem i cal cl asses and pest i c i d e deg r adat es i n

e nvir onme n ta l wa te r sa mple s. I t wa s

developed by the USGS for use in the

NW QL . The method combines octadecy l

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 2

### (C-18) SPE for pesticide isolation GC/MS

operated in the selected-ion monitoring mode

( S I M ) f o r

se le c tive c onf ir

ma tion a nd

qua ntita tion of the analytes

. 1 

### The method

was developed to co mplement method 2001

by using the sa me sa mple preparation and

anal y t i cal st eps but adds new anal y t es.

Ex tracts from method 2001 can be analy z ed

by the new method 2002 to ex pand the rang e

of analy t es determined from one water

sam p l e , because t h e sam e sam p l e preparat i on

procedures are followed. The method was

implemented in the NW QL in March 1999 for

conditional analy s is of e nvir onme n ta l sa mple s

collected as part of the NAW QA prog ram.

This report provi des a detailed

description of all aspects of the methods,

including the equipment, reag ents, sampling

protocol, instrument calibration, and SPE

procedure required for sample analy s is.

Method performance (bias and variability ),

holding time s in wa te r a nd a f te r isola tion on

the SPE c o lumn, a nd e s tima te d m e thod

de t e c t ion lim it s for 75 anal y t es are present e d.

The scope of the report includes

determination of method performance in

r e a g e n t- wa te r sa mple s a nd in two na tur a lwater ty pes—a g r ound-water and a surfacewater sample from th e Denver, Colorado,

reg i on. Method performance was determined

at two concentra tion levels—0.1 and 1.0

microg r am per liter (μg / L ) —in each water

ty

pe. Method detecti on limits were estimated

accordi n g t o an accept e d st at i s t i cal procedure

(U.S. Environmental Protection Ag ency

, 1997). Holding times of the analy t es in water

before ex traction and on the SPE columns

following ex traction and column dry i ng were

evaluated. An optiona l la bor a t or y

a

u toma te d

procedure is describe d, and an optional onsite SPE procedure is briefly described in

Supplements A and B in this report.

1 

### Words in boldface are defined in the G l ossary

. 

### IN ITIA L M E TH OD D EVELOPM E N T

This method was developed to

complement the ex isting method 2001 by

adding a new suite of pe stic ide s a nd pe stic ide

deg r adates without modi fy ing the analy tical

procedure. Method deve lopment consisted of

testing the new analy t es by using the 2001

procedure and collec ting method validation

inf o r

m a tion on the a n a l y t e s tha t we r e suita ble to

the GC/MS a nd SPE c onditions use d. I n itia l

method development included obtaining

anal y t i cal st andards of t h e parent pesticides and

deg r adat es i d ent i f i e d as candi dat e anal y t es.

The new anal y t es were t e st ed by GC / M S and

deem ed accept a bl e i f t h ey provi ded m easurabl e

response and narrow chromatog r aphic peak

shapes. The anal y t es t h en were com b i n ed i n t o

mix tures of parent or de g r adates and added to

r e a g e n t- wa te r sa mple s to de te r mine initia l

f e a s ibility of r e c ove r y

using C- 18 SPE. The

a n a l y t e s tha t we r e te ste d initia lly but

subsequently eliminated from the method

because of low GC/MS response or C-18 S P E

recovery are listed in table 1.

Eig h t parent pesticid es, most of which

were sel ect ed because of t h ei r hi g h nat i onal

- use

rate, had low or no GC/MS response (x g c ) and

we r e e limina t e d f

r o m a dditiona l te sting

(table 1). Acephate and methamidophos had

low SPE recovery (x spe), and chlorethox y f os

wa s not obta i ne d in time to inc l ude in te sting

(x or). L i kewise, 14 deg r adates had low or no

GC/MS response (x g c ), and 9 deg r adates had

low SPE r e c ove r y

( x spe ) dur ing pr e limina r y testing

, so the compounds were not included in

a dditiona l te sting

. Nine de g r a d a t e s liste d in

vendors' catalog s were out of stock during

te sting a nd the r e f or e c ould not be considered

for method validation (x or).

Initial Metho d Dev e lopm ent 34 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr yTable 1.Analytesthat wereinitiallyconsidered ortested but subsequentlyeliminated fromcomplete validation experimentsbecause ofproblemswith ordering, analysis, orrecovery[Analytesseparated byparentsand degradates, and sorted accordingto rank.Parentpesticidesshownfor correspondingdegradates.Rank,nationalpesticideuse rankofanalyte; CASRN, Chemical AbstractsService RegistryNumber; P-Code, National Water InformationSystemparameter code; xor,problemobtainingchemical standard; xgc, problemwithgaschromatograph/mass spectrometer analysis; xspe, problems withsolid-phase extractionrecoveryor instabilityinwater; VOC, volatile organic compound; 2002x, parentpesticide initiallytested but eliminated frommethod;–, noCASRNorparameter code available]RankCASRNP-CodeShortnameUseClassProblemParentCASRNParentnameParentclassParentmethodParent pesticides3730560-19-161579AcephateInsecticideOrganophosphorusxspe––––5887674-68-861588DimethenamidHerbicideAmidexgc––––7059669-26-061608ThiodicarbInsecticideCarbamatexgc––––78133-06-261582CaptanFungicideImidexgc––––9810265-92-661597MethamidophosInsecticideOrganophosphorusxspe––––101115-32-261587DicofolAcaricideOrganochlorinexgc––––10476-06-261584ChloropicrinFumigantVOCxgc––––153300-76-538856NaledInsecticideOrganophosphatexgc––––15566841-25-661609TralomethrinInsecticidePyrethroidxgc––––23395465-99-961581CadusaphosNematocideOrganophosphorusxgc––––23454593-83-861583ChlorethoxyfosInsecticideOrganophosphorusxor––––Degradates1003120-83-2346022,4-DichlorophenolDegradate–xspe94-75-72-4,DChlorophenoxyacid20501007–616192-Chloro-2’,6’_alideDegradate–xor15972-60-8AlachlorAcetanilide200110126515-38-4616263,5,6-Trichlor_dinolDegradate–xgc2921-88-2ChlorpyrifosOrganothiophosphate2001101610548-10-461675Terbufos-sulfoxideDegradate–xor13071-79-9TerbufosOrganothiophosphate20011026–61658Metribuzin-des_iketoDegradate–xspe21087-64-9MetribuzinTriazine20011026–61657Metribuzin-desaminoDegradate–xspe21087-64-9MetribuzinTriazine200110281113-02-661639OmethoateDegradate–xspe60-51-5DimethoateOrganothiophosphate200210342588-04-761667PhoratesulfoneDegradate–xspe298-02-2PhorateOrganothiophosphate20011043–616223-(2,2-Dichlor_acidDegradate–xgc52645-53-1PermethrinPyrethroid2001Table 1.Analytesthat wereinitiallyconsidered ortested but subsequentlyeliminated fromcomplete validation experimentsbecause ofproblemswith ordering, analysis, orrecovery—Continued

Initial Method D evelopment 5RankCASRNP-CodeShortnameUseClassProblemParentCASRNParentnameParentclassParentmethod1049100-02-7346474-NitrophenolDegradate–xspe56-38-2ParathionOrganothiophosphate200110512327-02-8617481-(3,4-Dichlor_)ureaDegradate–xgc330-55-2LinuronUrea2001106035884-76-561653Malathionmono_ acidDegradate–xor121-75-5MalathionOrganothiophosphate2001106465600-62-6616122,3,3-trichlor_saltDegradate–xgc2303-17-5TriallateThiocarbamate200110693964-56-5616324-Bromo-2-chlo_henolDegradate–xspe41198-08-7ProfenofosOrganothiophosphate2002107016752-77-549296MethomylDegradate–xgc59669-26-0ThiodicarbCarbamate2002x107013749-94-561655Methomyl-oximeDegradate–xgc59669-26-0ThiodicarbCarbamate2002x1078––TetrahydrophthalimideDegradate–xor133-06-2CaptanImide20021084934-32-7616162-AminobenzimidazoleDegradate–xgc17804-35-2BenomylCarbamate9060108410605-21-738736CarbendazimDegradate–xgc17804-35-2BenomylCarbamate906010862814-20-2616212-Isopropyl-6-_dinolDegradate–xspe333-41-5DiazinonOrganothiophosphate20011086962-58-361638Diazinon,oxyg_nalogDegradate–xgc333-41-5DiazinonOrganothiophosphate20011093–616243-(3,5-Dichlor_imideDegradate–xor36734-19-7IprodioneAmide20021101–616132,4'-DicofolByproduct–xgc115-32-2DicofolOrganochlorine200211143739-38-6616283-PhenoxybenzoicacidDegradate–xgc52315-07-8CypermethrinPyrethroid2002112431110-62-061661O-Ethyl-S-prop_ioateDegradate–xgc13194-48-4EthopropOrganothiophosphate200111285459-93-861659N-Ethylcycloh_amineDegradate–xspe1134-23-2CycloateThiocarbamate20021129–616233-(2,2-Dichlor_ylateDegradate–xgc68359-37-5CyfluthrinZyrethroid20021134–61643EthiondioxonDegradate–xor563-12-2EthionOrganothiophosphate200212273761-42-061648FenthionsulfoneDegradate–xor55-38-9FenthionOrganothiophosphate20021228–61651Isophenphos-de_logueDegradate–xor25311-71-1IsofenphosOrganothiophosphate20021228–61650Isophenphos-de_ropylDegradate–xor25311-71-1IsofenphosOrganothiophosphate2002123217210-55-861673TemephossulfoxideDegradate–xgc3383-96-8TemephosOrganothiophosphate2002

### AN AL Y T I C AL M E T H O D

Organic Compounds and Parameter

C odes: Pest icides and degradat es,

f ilt ered, gas chromat ography /mass

spectrometry

, Laboratory methods

( schedules) 2002 and 2011

( U .S. Geological Surv ey

Method O-2002-01)

1. Scope and A pplication

The method is suitable for the

de te r mina tion of low- le ve l c onc e n tr a tions ( 1

to 1,000 nanog rams per liter) of pesticides

a nd pe stic ide de g r a d a t e s in f ilte r e d na tur a lwater samples. The met hods are applicable to

pest i c i d es and deg r adat es t h at are (1)

e f

f i c i e n tly pa r titione d f r o m the wa te r pha se

onto a C-18 org a nic phase that is chemically

bonded to a solid porous silica matrix , and (2)

suf f i c i e n tly vola tile a nd the r ma lly sta b le f o r

g a s chromatog r aphy

. Suspended particulate

ma tte r is r e move d f r o m the sa mple s by

filtration, so this method is suitable for

pest i c i d es and deg r adat es i n t h e di ssol v ed

pha se . The qua ntity of pe stic ide dissolve d in

wa te r in r e la tion to tha t a d sor b e d to se dime nt

depends on the phy sical and chemical

properties of the pe stic ide a nd the

concentration of suspe nded sediment in the

water.

The sa mple pr e p a r a tion a nd e sse ntia l

GC/MS operational procedures used for the

new method are identical to those in method

2001, which was developed for more

abundantly and widely used pesticides (Z aug g

and others, 1995). The common preparation

a nd ope r a tiona l pr oc e dur e s will a llow a n a l y s is

of ex tracts by either method, or analy s is of

analy t es in both methods from one watersample ex tract. The 2001 method included an

optional on-site ex trac tion procedure, and

different laboratory me thod numbers were used to disting u ish laboratory SPE (2001) and

on-site SPE (2010). Similarly

, the new

method numbers disting u ish laboratory SPE

(2002) and on-s ite SPE (2011).

The analy t es include parent pesticides of

national importance ba sed on their use and

application or importance to the rereg i stration monitoring needs of the U.S.

Environmental Protection Ag ency (USEPA)

Office of Pesticide Prog rams, and deg r adates

of pesticides included in NW QL methods

2001, 2050, or the new method 2002

presented in this report (table 2). The USEPA

is r e vie w ing olde r pe stic ide s ( t hose initia lly

reg i stered prior to November 1984) under the

F e de r a l I n se c tic ide

, F ung ic ide

, a nd

Rode ntic ide Ac t to e n sur e tha t the y me e t

current scientific and reg u l a t o ry st andards

(U.S. Environmental Protection Ag ency

, 2001). Selection of pa rent pesticides was

based on national pestic ide

- use inf o r

m a tion

from the National Center for F ood and

Ag ricultural Policy and the Census of

Ag riculture (Majewski, 1997). The pesticides

we r e sor t e d in de c r e a s ing or de r by tota l ma ss

of

a c tive ing r e d ie nt a pplie d a nd tota l tr e a t e d

area. The top 120 were determined by

combining the top 100 in total quantity used

and the top 100 in tota l area of land treated

(80 are in the top 100 by both criteria). The

120 compounds were considered a hig h

pr ior ity f

o r

the NAWQA pr og r a m ( M a j e w ski,

1997). F i fty

- seven of these compounds were

not inc l ude d in e x isting NWQL a n a l y tic a l

methods. These compounds were classified

by phy si cal at t r i but es, such as chem i cal cl ass,

characteristic functiona l g r oups, and possible

anal y t i cal t echni que. Seventeen pesticides

we r e c onside r e d suita ble f o r

te sting by

GC/MS a nd we r e initia lly inc l ude d in the s e

methods. The USEPA reviewed the resulting

list, a nd se t pr ior itie s or a dde d pe stic ide s of

impor ta nc e to its pe stic ide r e

- r e g i str a tion

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 6

### process. Selection of pest i c i d e deg r adat es

initia lly wa s ba se d on whe t he r the pa r e nt

pesticide was determin ed by NW QL methods

2001, 2050, or the current method, and

whet her an anal y t i cal st andard was readi l y available. These compounds then were

cl assi fi ed by phy si cal at t r i but es, such as

chemical class, ava ilable functional g r oups,

and whether they would be amenable to the

C-18 SPE GC/MS analy tical method.

Se ve nty

- thr e e de g r a d a t e s initia lly we r e

considered.

Aft e r t h i s sel ect i on process, t h e anal y t es

we r e obta i ne d a nd te ste d in initia l a nd f i na l

val i d at i on ex peri m e nt s. The anal y t es t h at

successfully passed th e f i na l va lida tion

e x pe r ime nts a r e liste d in ta ble 2. The r e la tions

of pesticide deg r adates included in the new

method to parent pesticides in U.S.

Geolog ical Survey methods 2001, 2050, and

2002 are listed in table 3.

All ta ble s in this r e por t list the a v e r a g e

national-use rank of pe stic ide or pe stic ide

deg r adat e t o al l o w sort i n g of t h e anal y t es and

to provide an easy correlation between parent

and deg r adat e pest i c i d es. The pest i c i d es

sor t e d in de c r e a s ing or de r in tota l kilog r a m s

of

a c tive ing r e d ie nt a pplie d a nd tota l tr e a t e d

hect ares were assi g n ed numbers indicating

their order (or rank). The arithmetical

averag e of the rank on the basis of total

kilog r ams of active ing r edient applied and

t o t a l t r eat ed hect ares was cal cul a t e d and i s

termed the " r ank" in this report. Deg r adates

were arbitrarily assig n ed a rank of 1000 plus

t h e averag e rank of t h e parent pest i c i d e. For

ex ample, 2-[ 2 -ethy l -6-methy lpheny l)amino]

-

1- pr opa nol a nd 2- e t hy l- 6- me thy l a n iline

, both

deg r adates of metolachlor, which has an

averag e rank of 2, are assi g n ed averag e rank

1002 (table 3). This ranking procedure

provides a convenient way to link the

deg r adates and parent pe stic ide s in ta ble s a nd

fi g u res. Because som e deg r adat es pot ent i a l l y can be derived from more than one parent

pesticide, some of the deg r adates in table 2

are listed more than once, in order of the

national-use rank of the pa rent pesticide. I n

that situation, the deg r adate was assig n ed the

lowest rank, even thoug h the deg r adate could

have a different ra nk, depending on which

parent it was derived from. F o r ex ample, 3,4-

dic h lor o a n iline is shown in ta ble 2 with r a nk

1033, even thoug h it could be assig n ed ranks

of 1036, 1051, and 1241, which correspond to

the three other potentia l parent pesticides

(linuron, propanil, ne buron) of hig h to

moderate national use.

A short, 20-character name was used in

the tables to minimiz e space taken by leng thy

chem i cal nam e s. The short name was defined

as t h e fi rst 14 charact ers and t h e l a st 5

charact ers of a nam e , j o i n ed by an

underscore: “_”. Common or chemical

names and corresponding short names are

liste d in ta ble 2.

The calibration rang e is equivalent to

concentrations rang ing from 0.001 to 1.0 μg /L

for most analy t es. The method detection limit

(MDL ) is not only compound dependent, but

also depends on sample ma tr ix , instr u me nt

performance, and other operational sources of

variation. F o r all analy t es listed in table 2,

MDL s in pe stic ide

- g r a d e wa te r va r y

f

r o m

0.001 to 0.7 μg /L . Analy tical results are not

censored at t h e MDL ; i f a pest i c i d e m eet s t h e

de te c tion c r ite r i a ( r e te ntion time a nd ma ss

spect ra com p ared t o t h at of a reference

standard, as defined la ter in section 11), the

r e sult is c a l c u la te d a nd r e por te d with a n

e s tima te d “ E ” qua lif ie r

.

A n aly t ical Method 78 D

by CTable2. Pesticidesand degradatesincluded in newmethod

e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr y[Table sortedbyremarkcodeandthenbyrank.Rank,national rankofpesticide basedonapplicationrate. Pesticide degradateswere arbitrarilyassigned a rankof1000 plusthe average rankofthe lowest-ranked parentpesticide;CASRN,ChemicalAbstractsService RegistryNumber;PCode, National Water InformationSystemparametercode;I,Insecticide;H,Herbicide;Def,Defoliant;N,Nematocide;F,Fungicide;PGR,PlantGrowthRegulator;Deg,Degradate; Fum,Fumigant; IS, InternalStandard; SUR, Surrogate; –,not applicable; E, estimatedremarkcode; --,CASRN not available]RankNameShortnameCASRNP-CodeUseClassRemarkcodeParent pesticides63PrometrynPrometryn7287-19-604036HTriazine—69ProfenofosProfenofos41198-08-761603IOrganothiophosphate—71alpha-Endosulfanalpha-Endosulfan959-98-834362IOrganochlorine—75MetalaxylMetalaxyl57837-19-161596FAmino acid derivative—106OxyfluorfenOxyfluorfen42874-03-361600HDiphenylether—108cis-Propiconazolecis-Propiconazolec-60207-90-1179846FTriazole—110trans-Propiconazoletrans-Propiconazolet-60207-90-1179847FTriazole—121MyclobutanilMyclobutanil88671-89-061599FTziazole—126FenamiphosFenamiphos22224-92-661591NOrganothiophosphate—127HexazinoneHexazinone51235-04-204025HTriazine—128CycloateCycloate1134-23-204031HThiocarbamate—132MethidathionMethidathion950-37-861598IOrganothiophosphate—134EthionEthion563-12-282346IOrganothiophosphate—211(E)-Dimethomorph(E)-Dimethomorphe-110488-70-5179844FMiscellaneous—212(Z)-Dimethomorph(Z)-Dimethomorphz-110488-70-5179845FMiscellaneous—220TerbuthylazineTerbuthylazine5915-41-304022HTriazine—225FlumetralinFlumetralin62924-70-361592PGRDinitroaniline—227FenthionFenthion55-38-938801IOrganothiophosphate—228IsofenphosIsofenphos25311-71-161594IOrganothiophosphate—229PropetamphosPropetamphos31218-83-461604IOrganothiophosphate—231TebupirimphosTebupirimphos96182-53-561602IOrganothiophosphate—28DimethoateDimethoate60-51-582662IOrganothiophosphateE30TribuphosTribuphos78-48-861610DefOrganothiophosphateE71beta-Endosulfanbeta-Endosulfan33213-65-934357IOrganochlorineE76TefluthrinTefluthrin79538-32-261606IPyrethroidE83DicrotophosDicrotophos141-66-238454IOrganophosphateETable 2.Pesticidesand degradatesincluded in newmethod—Continued

Analytical MethodRankNameShortnameCASRNP-CodeUseClassRemarkcode93IprodioneIprodione36734-19-761593FAmideE102CyhalothrinCyhalothrin91465-08-661595IPyrethroidE114CypermethrinCypermethrin52315-07-861586IPyrethroidE115SulprofosSulprofos35400-43-238716I0rganothiophosphateE125PhosmetPhosmet732-11-661601IOrganothiophosphateE129CyfluthrinCyfluthrin68359-37-561585IPyrethroidE131BifenthrinBifenthrin82657-04-361580IPyrethroidE230SulfoteppSulfotepp3689-24-561605IOrganothiophosphateE232TemephosTemephos3383-96-861607IOrganothiophosphateEDegradates10022-[2-Ethyl-6-methylphenyl)amino]-1-propanol2-[2-Ethyl-6-m_panol61520-53-461615Deg——10072-Chloro-2,6-diethylacetanilide2-Chloro-2,6-d_ilide6967-29-961618Deg——10084-(Hydroxymethyl)pendimethalin4-(Hydroxymeth_halin56750-76-661665Deg——1016Terbufos-O-analoguesulfoneTerbufos-O-ana_lfone56070-15-661674Deg——10333,4-Dichloroaniline3,4-Dichloroaniline95-76-161625Deg——10433-Phenoxybenzylalcohol3-Phenoxybenzy_cohol13826-35-261629Deg——1044c-Methyl-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane)-carboxylatec-Methyl-3-(2,_ylate1c-61898-95-179842Deg——1044t-Methyl-3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane)-carboxylatet-Methyl-3-(2,_ylate1t-61898-95-179843Deg——1049Paraoxon-ethylParaoxon-ethyl311-45-561663Deg——1060MalaoxonMalaoxon1634-78-261652Deg——10622-(4-tert-butylphenoxy)-cyclohexanol2-(4-tert-buty_xanol1942-71-861637Deg——1067DisulfotonsulfoneDisulfotonsulfone2497-06-561640Deg——1067DisulfotonsulfoxideDisulfotonsulfoxide2497-07-661641Deg——1071EndosulfansulfateEndosulfansulfate21031-07-861590Deg——1076Tefluthrinmetabolite [R152912]Tefluthrinmet_2912]--61672Deg——10933,5-Dichloroaniline3,5-Dichloroaniline626-43-761627Deg——10992,5-Dichloroaniline2,5-Dichloroaniline95-82-961614Deg——1124O-Ethyl-O-methyl-S-propylphosphorothioateO-Ethyl-O-meth_ioate76960-87-761660Deg——

910 D

by CTable 2.Pesticidesand degradatesincluded in newmethod—Continued

e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr yRankNameShortnameCASRNP-CodeUseClassRemarkcode1126FenamiphossulfoneFenamiphossulfone31972-44-861645Deg——1231TebupirimphosoxygenanalogueTebupirimphos,_logue--61669Deg——10022-Ethyl-6-methylaniline2-Ethyl-6-meth_iline24549-06-261620Deg—E1012ChlorpyrifosoxygenanalogChlorpyrifos,_nalog5598-15-261636Deg—E10132-AminoN-isopropylbenzamide2-AminoN-isop_amide30391-89-061617Deg—E1014Paraoxon-methylParaoxon-methyl950-35-661664Deg—E10154-Chloro-2-methylphenol4-Chloro-2-met_henol1570-64-561633Deg—E10243-Trifluoromethylaniline3-Trifluoromet_iline98-16-861630Deg—E10321-Naphthol1-Naphthol90-15-349295Deg—E10321,4-Naphthaquinone1,4-Naphthaquinone130-15-461611Deg—E1034Phorate oxonPhorate oxon2600-69-361666Deg—E1053Azinphos-methyl-oxonAzinphos-methyl-oxon961-22-861635Deg—E1054FonofosoxygenanalogFonofos,oxyge_nalog944-21-861649Deg—E1071EndosulfanetherEndosulfanether3369-52-661642Deg—E1076Tefluthrinmetabolite [R119364]Tefluthrinmet_9364]--61671Deg—E11014,4'-Dichlorobenzophenone4,4'-Dichlorob_enone90-98-261631Deg—E11054-Chlorobenzylmethylsulfone4-Chlorobenzyl_lfone98-57-761634Deg—E1125PhosmetoxonPhosmetoxon3735-33-961668Deg—E1126FenamiphossulfoxideFenamiphossulfoxide31972-43-761646Deg—E1134EthionmonoxonEthionmonoxon17356-42-261644Deg—E1153DichlorvosDichlorvos62-73-738775FumOrganophosphateE1227FenthionsulfoxideFenthionsulfoxide3761-41-961647Deg—EInternalstandards—Acenaphthene-d10Acenaphthene-d1015067-26-2—IS——Chrysene-d12Chrysene-d121719-03-5—IS——Phenanthrene-d10Phenanthrene-d101517-22-2—IS——Surrogates—alpha-HCH-d6, surrogatealpha-HCH-d6,_ogate319-84-6-d699224SUR——Diazinond10,surrogateDiazinond10,_ogate100155-47-399223SUR——1Letter prefixadded to CASRN becauseCASRN not available forcis-,trans-or E-, Z-isomers.2CASRNnumber for endosulfansulfate waschanged from"1031-07-7"to"1031-07-8"inthe electronic (pdf) file, February4, 2002(mws).Table 3.Relation ofpesticide degradatesincluded in newmethod to parent pesticidesin U.S. Geological Surveymethods2001, 2050, and 2002[Table sorted byincreasingorder ofdegradate-use rank,thenparentpesticide-use rank.Somedegradateshavemore thanone possible parentpesticide,butuselowestrank.Degradaterank,national-userank ofdegradateusedintable1;P-Code,NationalWaterInformation Systemparameter code;CASRN, Chemical AbstractsService RegistryNumber; Degradate shortnameandcorresponding long namegiven intable1;--,noCASRN available;–, noParentmethod]DegradaterankP-CodeCASRNDegradateshort nameParent CASRNParent nameParent method10026162024549-06-22-Ethyl-6-meth_iline51218-45-2Metolachlor200110026161561520-53-42-[2-Ethyl-6-m_panol51218-45-2Metolachlor20011007616186967-29-92-Chloro-2,6-d_ilide15972-60-8Alachlor200110086166556750-76-64-(Hydroxymeth_halin40487-42-1Pendimethalin20011012616365598-15-2Chlorpyrifos,_nalog2921-88-2Chlorpyrifos200110136161730391-89-02-Amino-N-isop_amide25057-89-0Bentazon2050101461664950-35-6Paraoxon-methyl298-00-0Methylparathion20011015616331570-64-54-Chloro-2-met_henol194-74-6MCPA(andsaltsand esters)20501015616331570-64-54-Chloro-2-met_henol194-81-5MCPB (andsaltsand esters)205010166167456070-15-6Terbufos-O-ana_lfone13071-79-9Terbufos200110246163098-16-83-Trifluoromet_iline12164-17-2Fluometuron2050103261611130-15-41,4-Naphthaquinone163-25-2Carbaryl200110324929590-15-31-Naphthol163-25-2Carbaryl2001103261611130-15-41,4-Naphthaquinone115299-99-7Napropamide200110324929590-15-31-Naphthol115299-99-7Napropamide200110336162595-76-13,4-Dichloroaniline1330-54-1Diuron205010336162595-76-13,4-Dichloroaniline1709-98-8Propanil200110336162595-76-13,4-Dichloroaniline1330-55-2Linuron200110336162595-76-13,4-Dichloroaniline1555-37-3Neburon20501034616662600-69-3Phorateoxon298-02-2Phorate2001104461629313826-35-23-Phenoxybenzy_cohol52645-53-1Permethrin20011044798423c-61898-95-1c-Methyl-3-(2,_ylate52645-53-1Permethrin20011044798433t-61898-95-1t-Methyl-3-(2,_ylate52645-53-1Permethrin20011044798423c-61898-95-1c-Methyl-3-(2,_ylate52315-07-8Cypermethrin20021044798433t-61898-95-1t-Methyl-3-(2,_ylate52315-07-8Cypermethrin20021044798423c-61898-95-1c-Methyl-3-(2,_ylate68359-37-5Cyfluthrin20021044798433t-61898-95-1t-Methyl-3-(2,_ylate68359-37-5Cyfluthrin2002

Analytical Method 1112 D

by CTable 3.Relation ofpesticide degradatesincluded in newmethod to parent pesticidesin U.S. Geological Surveymethods2001, 2050, and 2002—Continued

e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr yDegradaterankP-CodeCASRNDegradateshort nameParent CASRNParent nameParent method104961663311-45-5Paraoxon-ethyl56-38-2Parathion2001105361635961-22-8Azinphos-methyl-oxon86-50-0Azinphos-methyl2001105461649944-21-8Fonofos,oxyge_nalog944-22-9Fonofos20011060616521634-78-2Malaoxon121-75-5Malathion20011062616371942-71-82-(4-tert-buty_xanol2312-35-8Propargite20011067616402497-06-5Disulfotonsulfone298-04-4Disulfoton20011067616412497-07-6Disulfotonsulfoxide298-04-4Disulfoton20011071615901031-07-7Endosulfansulfate959-98-8alpha-Endosulfan20021071615901031-07-7Endosulfansulfate33213-65-9beta-Endosulfan20021071616423369-52-6Endosulfanether959-98-8alpha-Endosulfan20021071616423369-52-6Endosulfanether33213-65-9beta-Endosulfan2002107661671--Tefluthrinmet_9364]79538-32-2Tefluthrin2002107661672--Tefluthrinmet_2912]79538-32-2Tefluthrin2002109361627626-43-73,5-Dichloroaniline36734-19-7Iprodione200210996161495-82-92,5-Dichloroaniline133-90-4Chloramben205011016163190-98-24,4'-Dichlorob_enone115-32-2Dicofol4–11056163498-57-74-Chlorobenzyl_lfone28249-77-6Thiobencarb200111246166076960-87-7O-Ethyl-O-meth_ioate13194-48-4Ethoprop20011125616683735-33-9Phosmetoxon732-11-6Phosmet200211266164631972-43-7Fenamiphossulfoxide22224-92-6Fenamiphos200211266164531972-44-8Fenamiphossulfone22224-92-6Fenamiphos200211346164417356-42-2Ethionmonoxon563-12-2Ethion200211533877562-73-7Dichlorvos2300-76-5Naled4–1227616473761-41-9Fenthionsulfoxide55-38-9Fenthion2002123161669--Tebupirimphos,_logue96182-53-5Tebupirimphos20021Degradatesmightalsobe formed fromone or more ofthe parentpesticidesasa result ofthermal degradationofthe parentpesticide inthe injectionportofthegas chromatograph during gas chromatography/massspectrometryanalysis.2Dichlorvosis alsoappliedas a parentpesticide.3Letter prefixadded to CASRN becauseCASRN not available forcis-,trans-or E-, Z-isomers.4Lastmodifed:February4, 2002 (mws).

### Permanently E-Coded Compounds

. Two classes of data a r e r e por te d f r o m the

method: (1) compounds that are reported

without qualification, and (2) compounds that

are alway s reported as estimated. Compounds

that are reported wit hout qualification are

reproducibly well recove red by the method, as

defined by median rec overies between 60 and

120 percent and with variation (as indicated

by the nonparametric statistic, relative F

pseudosig ma; Hoag lin, 1983) less than 25

percent. Estimated- value compounds, which

are " E -coded" in the data base, do not meet

these performance criteria for unqualified

quantification, but are re tained in the method

because the compounds are important owing

to hig h use or potentia l envi ronm ent a l effect s

and because anal y t i cal perform ance has been

consistent and reproduc ible. Estimated-value

compounds, when reported, have been

identified as present with a hig h deg r ee of

confidence according to method-specific

c r ite r i a

, but g r e a t e r unc e r ta inty e x ists in the

qua ntita tive de te r mina tion of c onc e n tr a tion

than for compounds reported without

qualification. I t is important to note,

howe v e r , tha t the r e is no qua lita tive

difference between unqualified compounds

and estimated-value compounds. The

identification of the compounds is equally

reliable, and, in reality , bias and variability

for different compounds span a continuum of

performance rather than corresponding to

categ ories. F o r ex ample, some unqualified

compounds perform similarlyto estimatedvalue compounds that fall just outside the

unqualified categ ory criteria. Thus, data users

should consider the estimated-value

desi g n at i on as a cat eg ori cal warni n g t o pay

e x tr a a tte ntion to pote n tia l use a nd a d justme nt

of num eri cal concent r a tion results, but not as

a distinct boundary between acceptable and

unaccept a bl e dat a , as defi ned at t h e beg i nni ng

of this parag r aph. 2. Summary of Method

Wa te r sa mple s a r e f ilte r e d a t the

c o lle c tion site by using g l a ss- f i be r f

ilte r s with

nominal 0.7-μm pore diameter to remove

particulate material (Sandstrom, 1995).

About 1 L of the filte red water sample is

pumped throug h a disposable, poly p ropy lene

SPE column that contains porous silica coated

with an octadecy l (C-18) phase that is

chemically bonded to the surface of the silica.

The SPE c o lumns a r e dr ie d using a g e ntle

stream of nitrog en to remove residual water.

The adsorbed anal y t es (pest i c i d es and

deg r adat es) t h en are rem oved from t h e S P E

columns by elution with 2 mL of ethy l

acet at e. A procedural i n t e rnal st andard i n

toluene is added, and the eluant is further

evaporated to a small volume (150 μL ) using

a g e ntle stream of nitrog en.

Ex tr a c t s a r e a n a l y z e d by a

c a p illa r y

c o lumn GC/MS ope r a te d in the SI M mode . The

anal y t es are i d ent i f i e d by com p ari n g t h ei r

r e te ntion time s a nd se le c t e d

- i on r a tios to

calibration standards an aly z ed under the same

GC/MS conditions. Analy t es are quantified by

relating the mass spectrometer (MS) response

of

the qua ntita tion ion of the a n a l y t e to the

qua ntita tion ion of a n internal standard

. Qua n tita tion of a n a n a l y t e a t a c onc e n tr a tion

le ss tha n the lowe st c a libr a tion sta nda r d or

g r e a t e r tha n the hig h e s t c a libr a tion sta nda r d is

qua lif ie d a s “ e s tima te d” ( E ) to sig n if y

the

l o wer confi d ence i n t h e ex t r apol at ed

concentration.

The inte r n a l sta nda r d qua ntita tion is a

procedural quantitation method in which the

inte r n a l sta nda r d is a dde d to the sa mple

e x tr a c t pr ior to e v a por ation and transfer-tovial sample-processing steps. The use of the

procedural internal st andar d quant it at ion

com p ensat e s for any bi as i n t h e ex t r act

A n aly t ical Method 13

### evaporation and transfer-to-vial sampleprocessing steps, but not the SPE and elution

steps of the analy tical method.

Surrogate anal y t es, whi c h are added t o

each sample in known concentration, are used

to monitor method performance with each

sa mple

.

A r e a g e n t- wa te r sa mple f o r tif ie d with

0.1 μg /L of the analy t es (a for t ifie d r e age nt

w a ter-set sam p le or a set spike) and a

pe stic ide

- g r a d e bla nk wa te r sa mple ( a

l a

borat ory reag ent bl a nk or set blank) are

ex t r act ed, processed, and anal y z ed wi t h each

set of 10 samples.

3. Int e rf erences

I n terferences mig ht be caused by

org a nic compounds that have g a sc h r o ma tog r a ph r e te ntion time s a nd

c h a r a c t e r istic ions with a ma ss ide n tic a l to

those of the pesticides and deg r adates of

interest. Contaminants in laboratory air,

solvents, reag ents (including water),

g l a sswa r e

, sa mple bottle s a nd c a p s, SPE

columns, and sample-processing equipment

c a n c a u se a r tif a c t s or f

a lse positive s in the

c h r o ma tog r a m s. All of the s e ma te r i a l s must

be routinely demonstrated to be free from

inte r f e r e nc e [le ss tha n the MDL

, or long

- t e r m

method detection level (L T–MDL ) , once

determined] under conditions of analy s is by

anal y z i n g l a borat ory reag ent bl anks.

Glassware must be washed with

de te r g e n t in hot wa te r and rinsed with tap

wa te r a nd distille d or de ionize d wa te r

. Glassware then should be drained, dried, and

heated in a laboratory furnace at 450°C for at

least 4 hours before use. Solvent rinsing with

methanol, followed by air dry i ng , may be

substitute d f o r

ove n he a ting f o r

othe r

equipment, including sample collection

bottle s, sa mple splitte r s , a nd f iltr a tion

devices. Ma tr ix inte r f e r e nc e s mig ht be caused by

cont am i n ant s t h at are coex t r act ed from t h e

sa mple . The e x te nt of ma tr ix inte r f e r e nc e s

will va r y , de pe nding on the na tur e of the

sa mple ma tr ix

.

Re sidua l c h lor i ne in tr e a t e d wa te r

sa mple s mig ht c a u se de g r adation of some

analy t es, especially org a nophosphorus

compounds (Dennis and others, 1979).

Suitable reag ents that mig ht be used to

de c h lor i na te c h lor i na te d wa te r sa mple s ha ve

not been t e st ed for t h ei r effect on al l anal y t es.

Pesticide deg r adates mig ht be formed by

deg r adation of the parent pe stic ide in the hot

i n

j e ct i on port of t h e GC . These deg r adat es are

consi d ered art i f act s of t h e anal y t i cal process,

and are not represent a t i v e of t h e concent r at i on

of

a n a l y t e s in the wa te r sa mple s. The e x te nt

of GC injection-port deg r adation depends on

a num ber of fact ors, i n cl udi ng surface

a c tivity , qua ntity of c o e x tr a c t e d or g a nic

ma te r i a l , a nd e x te nt of impur itie s on the

inje c tion- por t line r . De g r a d a t e s tha t a r e

susc e p tible to this the r ma l de g r a d a tion a r e

identified in table 3. F o r ex ample, 3,4-

dic h lor o a n iline c a n be f o r

m e d f

r o m the r ma l

deg r adation of diuron if it is in the wa te r

sa mple

.

4. A pparatus and Instrumentation

4.1 Manual sample ex traction

4.1.1 Cleaning and elution

module for SPE columns —Supelco, I n c.,

Visiprep Solid-Phase Ex traction Vacuum

Manifold and Visidry Dry i ng Attachment or

equivalent.

4.1.2 SPE pump, ceramic-piston,

val vel ess pump —Capable of pumping 0 to 30

mL /min, with fitting s for 3.18-mm outside

diameter (OD) tubing ; F l uid Metering I n c.,

Model QSY - 2 CKC or equivalent. F o r onD e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 14

### site SPE, an SPE pump powered by a 12-V dc

motor is needed; F l uid Metering I n c., Model

RHB - 0 CKC or equivalent.

4.1.3 Teflon-perfluoralkoxy

( PFA) tubing —3.18-mm OD; Cole-Parmer

I n strument Co., CL

- 06375-01 or equivalent.

4.1.4 T e f

z el -et h yl enet et raf l uoroe t hy le ne ( T

e f

ze l- ETFE) fe male Lue r

connector with 1/4-28 thread —Tefz e l-ETF E

union with 1/4-28 thread, and Tefz el-ETF E

nut with 1/4-28 thread and 3.18-mm OD

tubing connector; Upc hurch Scientific or

equivalent.

4.1.5 Pump control box

( optional) —F or 12- V dc pumps, f itte d with a

4-A fuse, tog g l e switch, and 10-ohm 1.58-A

variable resistor.

4.1.6 Sample-preparation

workstation ( optional)

— For pre-cl eani n g S P E

c o lumn; Z y ma r k

I n c ., B e nc hMa t e I I

W o rkstation or equivalent.

4.1.7 Bottle

- t op solv e n t

dispenser —Adjustable from 2 to 10 mL ;

B r inkman Dispensette, Van W a ters & Rog e rs

( V WR) Sc ie ntif ic or e quivalent, for adding

solve n ts to SPE c o lumns dur ing ma nua l

cleaning and conditioning steps.

4.1.8 L u er f l o w

- cont rol val ves ( optional) or on-off valves —Constructed of

ine r t ma te r i a l s; B u r d ic k & J a c k son ( B & J )

I n ert PTF E flow-control valve, B a x t er

Diag nostics, I n c. or equivalent.

4.1.9 Vacuum pump —Any

vacuum pump with sufficient capacity to

maintain a slig ht vacuum of 1.5 to 3 kPa in

the cleaning / elution module.

4.2 Automated sample ex traction

4.2.1 Zy m a rk I

n c

. Aut o T r ace

SPE W o rkstation— Config ured for 3-mL SPE columns. The setup conditions and

processi ng st eps for usi n g t h e Aut o Trace

W o rkstation are listed in Supplement A at the

end of this report.

I n the automated method,

e nvir onme n ta l a nd qua lity

- c ontr o l sa mple s

a r e e x tr a c t e d in ba tc he s of six

. The time

required for ex traction is 58 minutes. One

ope r a tor ty pic a lly c a n process 30 samples in

an 8-hour day using this apparatus.

4.3 Manual and auto mated sample

ex t r act i on

4.3.1 Micropipets —50- and 100-

μL , fix e d- and variab le-volume micropipets

with disposa b le g l a ss c a p illa r i e s ; VWR

Sc ie ntif ic or equivalent.

4.3.2 Analytical balances

— Capable of accurately weig hing 1,200 ±1 g

(water samples), 10.0000 g ±0.0001 g (SPE

columns), and 10.000 g ±0.001 mg (analy tical

standards).

4.3.3 Automate d solv e n t

evaporator —The sam p l e ex t r act s are

concent r at ed wi t h a Z y m a rk TurboVap L V

. The TurboVap water bath is set to 30°C, and

nitrog en g a s pressure is adjusted to 28 kPa.

4.4 Sample analy s is

4.4.1 GC/MS instrument—

Ag ilent Technolog ies Model 5890 Series I I

g a s chromatog r aph, connected via capillary

direct interface to an Ag ilent Technolog ies

5971 or 5972 mass selective detector (MSD).

4.4.2 Fuse d- silic a c apillary

col u mn —Provides adequate resolution,

capacity , accuracy , and variability . A 30-m

by 0.25-mm inside diameter (I D) fused-silica

capillary column coated with a 0.10-μm

bonded film of 95-percent dimethy l 5-percent

dipheny l poly s ilox a ne is used; Ag ilent

Technolog ies HP-Ultra I I or equivalent.

A n aly t ical Method 15

### 4.4.3 Recommended GC

conditions— Oven, 85°C (hold 1.5 min), then

prog ram to 240°C at 4°C/min, then prog ram

to 340°C at 15°C/min and hold for 2 minutes;

injection port, 225°C; carrier g a s, helium;

column flow nominal 0.65 mL /min (30

c m/se c line a r ve loc ity ) ; inje c tion volume

, 1 μL , splitle ss inje c tion; split- ve nt f l ow, 30

mL /min; se ptum pur g e , 1 mL /min. Tota l

a n a l y s is time is 49 minute s

.

4.4.4 Mass spectrometer

conditions— I n terface, 290°C; source, 180°C;

analy z er, 100°C; dwell time, 20 milliseconds;

ma ss ions monitor e d a r e liste d in ta ble 5 ( s e e

section 9, Calibration).

5. R eagent s and C onsumable

Ma te ri a l s

5.1 Helium carrier gas , 99.999

percent purity

.

5.2 Nitrogen gas, for S P E col u m n

dry i ng and solvent ev aporation, ultrapure.

5.3 SPE columns, I s olute C-18 (EC)

columns, packed with 500 mg of a C-18

hy drocarbon phase ch emically bonded to

silica (I nternational Sorbent Technolog y L t d.,

Mid Glamorg a n, UK). The C-18 phase is

end-capped to reduce polar secondary

interactions with surficial silanol g r oups. The

col u m n s use st ai nl ess-st eel fri t s t o keep t h e

sorbent phase i n pl ace.

5.4 Disposable culture tubes

, borosilicate g l ass, 16 by 100 mm, baked at

450°C for 2 hours; Kimax B r and, VW R or

equivalent.

5.5 Glass- fibe r filte rs , 0.7-μm nominal

pore diameter (GF / F g r ade), baked at 450°C

for 2 hours; W h atman, I n c. or equivalent.

5.6 Glass bottle s, ambe r ( G CC)

, 1,000-mL , 33-mm neck, baked at 450 o C for 2 hours, fitted with Te flon-lined screw caps;

NW QL GCC or equivalent.

5.7 Solvents , hex a ne, toluene, ethy l

acet at e, m e t h y l ene chl o ri de, and m e t h anol ;

B & J B r a nd ultr a pur e pe stic ide qua lity or

equivalent.

5.8 Pe stic ide

- grade wate r , any hig h

purity water such as ultrapure B & J B r and

wat e r for hi g h -perform ance l i qui d

chromatog r aphy (HPL C) or equivalent, that

has been tested and demonstrated to be free

f r o m a n a l y t e s a nd inte r f e r e nc e s in this

analy tical method.

5.9 De te rge n t solution, a dilute

mix ture (0.2 percent in tap water) of

laboratory

- g r ade phosphate-free liquid

deterg ent; L i quinox , Alconox I n c. or

equivalent.

6. Sampling Methods, SampleCollection Equipment, and

Cleaning Procedures

6.1 Sampling methods: Use sa mpling

methods capable of co llecting water samples

tha t a c c u r a te ly r e pr e s e n t the wa te r

- qua lity

characteristics of the surface water or g r ound

water at a g i ven time or location. Detailed

descriptions of sampling methods used by the

USGS for obtaining depth- and widthi n t e g r at ed surface-wat e r sam p l e s and of

sampling methods for obtaining g r ound-water

sa mple s, a nd of sa mple pr oc e ssing ( s plitting

, filtration, shipping ) are described by W ilde

and others (1999).

6.2 Sample-collection equipment: Use

sample-collection equipment, including

a

u toma tic sa mple r s , tha t a r e f r e e of tubing

,

g a skets, and other components made of

nonfluorinated plastic material that mig ht

l each i n t e rferences i n t o wat e r sam p l e s or sorb

t h e pest i c i d es and deg r adat es from t h e wat e r.

Ma te r i a l suita ble f o r

sa mple

- c olle c tion a nd

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 16

### processing equipment includes fluorocarbon

poly m ers (Teflon, ETF E) , metals (stainless

steel, aluminum), g l ass, and ceramics.

6.3 Sample filtration: Wa te r sa mple s

ne e d to be f ilte r e d pr ior to SPE using

procedures described by Sandstrom (1995).

F iltr a tion r e move s pa r tic ula t e ma te r i a l tha t

mig ht bloc k the SPE c o lumn. F ilte r the wa te r

samples as soon as possible after collection,

pr e f e r a b ly a t the sa mple

- c olle c tion site

, because filtration re moves microorg a nisms

t h at m i g ht deg r ade anal y t es.

6.4 Cleaning procedures: W a sh all

sample-collection equi pment with phosphatef r e e de te r g e n t, r i nse with ta p wa te r to r e move

al l t r aces of det e rg ent

, and fi nal l y ri nse wi t h

methanol (contained in a Teflon squeez ebottle )

. Allow the me tha nol to dr a i n a nd

evaporat e from t h e equi pm ent

. W h en dry

, cover equipment orifices with aluminum foil.

I f

it is not pr a c tic a l f o r

the me tha nol to

evaporat e from t h e equi pm ent

, use pest i c i d eg r a d e wa te r to r i nse me tha nol f r o m the

equipment.

N O TE: Methanol needs to be collected and

di sposed of i n accordance wi t h l o cal

reg u lations.

6.5 Quality

- c ontrol sample s:

Colle c tion of qua lity

- c ontr o l ( Q C) sa mple s is

a required component of sample collection for

wa te r

- qua lity studie s . QC sa mple s a r e

c o lle c t e d, usua lly a t the f i e l d site , to ide n tif y

,

qua ntif y

, a nd doc ume n t bia s a nd va r i a b ility in

data resulting from the collection, processing

, shipping , and handling of samples by field and

laboratory personnel. Th e ty pe, number, and

distribution of QC samp le s a r e de te r mine d by

the de sig n a nd da ta

- qua lity r e quir e me nts of

the study . Detailed discussion of the

description and purpose of QC sa mple s is

presented by W ilde and others (1999). 6.5.1 Blanks —The primary

purpose of a blank sample is to identify

potential sources of samp le contamination and

a sse ss the ma g n itude of c onta mina tion with

respect t o concent r at i on of t a rg et anal y t es.

Fi el d bl anks are col l ect ed and processed at t h e

f i e l d site in the sa me ma nne r a nd using the

same equipment as the environmental

sample(s). The field blank is comprised of an

aliquot of blank water processed sequentially

throug h each component of the sampling

sy stem. The source solution needed for blank

samples must be produ ced and certified by a

laboratory to have analy t e concent r at i ons t h at

do not ex ceed a specified method detection

limit. Pe stic ide

- g r a d e bla nk wa te r ( P B W ) a nd

vola tile

- g r a de bla nk wa te r ( V B W ) a r e

r e quir e d f o r

bla nks tha t will be a n a l y z e d f

o r

pesticides and volatile org a nic compounds,

respect i v el y

. VBW can al so be used for

pesticide blanks.

6.5.2 Re plic ate s —The primary

pur pose of r e plic a t e sa mple s is to ide n tif y

a nd

( o r ) qua ntif y

the va r i a b ility in a ll or pa r t of

the sa mpling a nd a n a l y s is sy ste m

. R e pl i cat es—envi ronm ent a l sam p l e s col l ect ed

in duplic a t e

, tr iplic a t e

, or hig h e r multiple s—

are consi d ered i d ent i cal i n com posi t i on and

are anal y z ed for t h e sam e chem i cal propert i e s.

6.5.3 Fortifie d matrix sample s

—

F o r tif ie d ( s pike ) sa mple s a r e use d to a n swe r

questions such as " W hat loss or g a in of targ et

anal y t es occurred because of wat e r-m at ri x

charact eri s t i c s; t h e fi el d processing , shipping

,

or

ha ndling pr oc e dur e s use d ; holding time ; or

l a

borat ory anal y t i cal pr ocedures? " A sample

is fortified by adding a mix tur e of ta r g e t

compounds obtained from the laboratory to an

e nvir onme n ta l sa mple a f te r the sa mple ha s

been processed. An unfortified environm e nt al sam p l e m u st accom p any each fort i f i e d

sample. Training is required before personnel

a tte mpt to f o r tif y

sa mple s. The f o r tif ic a tion

A n aly t ical Method 17

### kits provided to USGS personnel by the

NW QL include the fortification solution,

e quipme n t, bottle la be ls, a nd de ta ile d

instructions. The numbers and ty pes of matrix

samples used depend on the objectives and

da ta

- qua lity r e quir e me nts of individua l

studies, as determined by the project chiefs.

Althoug h analy s es for a set of fortified

sa mple s—la bor a t or y

f

o r tif ie d sa mple , f i e l df o r tif ie d sa mple , a nd f i e l d- f o r tif ie d

r e plic a t e —pr ovide the most c o mple te

inf o r

m a tion r e la ting to the pe r f o r

m a n c e of the

analy tical method, the data from only

la

bor a t or y

f

o r tif ie d sa mp les, or perhaps only

one field-fortified samp le, could be sufficient

to meet study needs.

7. St andards

7.1 Stock standard s : The pe stic ide s

and deg r adates were obt ained as pure materials

f r o m the USEPA Na tiona l Pe stic ide Sta nda r d

Repository (F t. Meade, Md.) or commercial

vendors (ChemService; EQ L a boratories).

Deuterated PAH standards in solution were

obtained from commercial vendors

(ChemService). I s otopica lly la be lle d pe stic ide

standards of diaz inon -d 10 

### and alpha -HC H -d 6 

### were purchased from Cambridg e I s otope

L a boratories (W oburn, Massachusetts).

7.1.1 Stock internal standard

( 200 ng/μL) —Prepare a 200-ng /μL

concentration of PAH in ternal standard by

accurately weig hing , to the nearest 0.001 mg

, 1 m g of t h e pure m a t e ri al of acenapht hene

d 10 

### , phenanthrene- d 10 

### , and chry sene- d 12 

### in a

5-mL volumetric flask and dilute to volume

with tolue n e

. Alte r n a tive l y

, the mix e d stoc k

may be obtained from commercial vendors.

Transfer t h e st ock st andards t o cl ean vi al s and

st ore i n a freez er. The st ock st andards are

stable for about 6 months. 7.1.2 Stock surrogate ( 100

ng/μL)

— Prepare a 100-ng /μL concentration

of surrog a te by accurately weig hing , to the

nearest 0.001 mg , 0.5 mg of diaz inon -d 10 

### and

alpha -HC H -d 6 

### in a 5-mL volumetric flask and

dilute with tolue n e

. Tr a n sf e r

the stoc k

standard to clean vials and store in a

refrig e rator at 4°C ± 3°C. The stock

standards are stable for about 6 months.

7.1.3 Stock standard ( 10,000

ng/μL)

— P r epare st andards of pesticides and

deg r adates of about 10,000 ng /μL by

accurately weig hing , to the nearest 0.001 mg

, 50 mg of the pure material in a 5-mL

vol um et ri c fl ask and di l u t e wi t h et hy l acet at e.

Transfer the stock standards to clean vials and

store in a refrig e rator at 4°C ± 3°C. The stock

standards for most compounds are stable for

about 6 months.

7.2 Primary c o mbine d fortific ation

standard ( 100-ng/μL)

— The stock standard or

standards are used to prepare two primary

combined fortification standards that contain

pest i c i d es and deg r adat es (there are too many

anal y t es t o i n cl ude al l parent s and deg r adat es

in one solution) . Alte r n a tive l y

, mix tur e s of

the analy t es may be obtained from

commercial suppliers. Prepare a 100-ng /μL

c onc e n tr a tion pr ima r y

c o mbine d f

o r tif ic a tion

standard by combinin g appropriate volumes

of the individual stock st andard in a 10- or 5-

mL volumetric flask. Use adj u st abl e

micropipet (0–50 or 0–100 μL ) to dispense an

appropriate volume into t h e vol um et ri c fl ask

and di l u t e wi t h et hy l acet at e. Transfer t h e

pr ima r y

c o mbine d f

o r tif ic a tion sta nda r d to a

cl ean vi al and st ore i n a refri g e rat o r. Thi s

standard is stable for about 6 months.

Alte r n a tive l y

, the pr ima r y

c o mbine d

fortification standard can be purchased as a

custom mix ture from a commercial vendor.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 18

### 7.3 Primary recovery standard

( 1 ng/μL) : P r epare a pri m a ry recovery

sta nda r d by diluting the pr ima r y

c o mbine d

fortification standards in 5-mL volumetric

flasks with methanol. St ore i n a refri g e rat o r at

4°C ± 3°C. Add a 100-μL aliquot of this

primary recovery sta ndard to a 1-L water

sample to obtain a concentration of 0.1 μg /L

for the method performance-evaluation

studies.

7.4 Polycyclic aromatic hydrocarbon

( PAH) internal standard ( 1 ng/μL) : P r epare a

dilute solution of the PAH inte r n a l sta nda r d

stock at 1 ng /μL with toluene. Transfer the

P AH i n t e rnal st andard t o a cl ean vi al and

store in a refrig e rator. This standard is stable

for about 6 months when refrig e rated. A

100-μL aliquot of this standard is added to

every sam p l e ex t r act t o quant i f y

anal y t e

concentrations.

7.5 Surrogate standard ( 1 ng/μL) :

Prepare a standard of diaz inon -d 10 

### and alpha

HC H -d 6 

### from the stock standard in methanol

at a concentration of 1 ng /μL

. Store in a

refrig e rator at 4°C ± 3°C. A 100-μL aliquot

of this standard is a dde d to e v e r y

sa mple to

monitor the e x tr a c tion a nd sa mple pr e p a r a tion

process.

7.6 Calibration standards: P r epare a

series of working calibration standards in

tolue n e tha t c onta i n a ll pe stic ide s a nd

deg r adat es at concent r at i ons rang i n g from

0.01 to 20.0 ng /μL

, as well as the surrog a te

a nd the PAH inte r n a l st andard at a constant

concentration of 1.0 ng /μL

. Prepare these

calibration standards by appropriate dilutions

of the 100-ng /μL primary combined

fortification, and surrog a te stock standards in 5- or 10-mL volumetric flasks (refer to

ta

ble 4) . Alte r n a tive l y

, prepare seri al di l u t i ons

of a 20-ng /μL calibration standard.

8. Gas C h romat ograph/M ass

Spect r omet er Perf ormance

8.1 Gas chromatog r aph performance

evaluation

8.1.1 The g a s chromatog r aph

performance normally is indicated by peak

shape and bythe variation of the selectedcompound (pesticide or deg r adate) response

factors relative to response factors obtained

by using a ne w c a p illa r y

c o lumn a nd f r e shly

prepared cal i b rat i on st andards. An ex am pl e

of the separation and peak shape of the

pesticides and deg r adates is shown in a total

ion chromatog r am of a 0.625-ng /μL standard

(fig

. 1). I f peak shape deteriorates or if

response factors fail to meet the calibration

cri t e ri a, ei t h er chang e t h e i n j ect i on l i n er or

ma inta in the c a p illa r y

c o lumn to br ing the g a s

c h r o ma tog r a ph into c o mplia nc e

. Pa r t of the

inle t e nd of the c a p illa r y

c o lumn c a n be

removed to restore perfo rm ance. S p eci fi cal l y

, a loss or g a in in response g r eater than 30

percent for pest i c i d es and deg r adat es

susc e p tible to loss on inje c tion indic a t e s a

need for immediate action.

8.2 Mass spectrometer performance

evaluation

8.2.1 Check the mass

spect rom e t e r pri o r t o anal y s i s for ex cessi ve

wat e r and ai r t h at woul d i ndi cat e l eaks i n t h e

vacuum. I f detected, l o cat e and fi x l eaks.

Also, check the instrument at the beg i nning of

each seri es of anal y s es t o ensure m a ss

spect rom e t e r perform ance accordi n g t o t h e

perfluorotributy l amine (PF T B A ) tuning

A n aly t ical Method 1920 D

by CTable 4.Volumesofprimarycombined fortification, internal, and surrogate standardsneeded to prepare suggested concentrationsofcalibrationstandards. Forcomparison, the equivalent concentration ofcalibration standardsin watersamplesisshown.

e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr y[ng/μL, nanogramper microliter; μL, microliter; mL, milliliter; μg/L, microgramper liter]Concentration of calibration standardsNominal concentration,inng/μL0.0190.0390.0780.1560.3120.6251.252.55.01020Volumeofprimarycombinedfortificationstandard (100 ng/μL), inμL1.953.97.815.615.631.262.51252505001,000Volumeofstockinternal standard(200 ng/μL), inμL5050505025252525252525Volumeofstock surrogatestandard(100 ng/μL), inμL100100100100100100100100100100100Final volumeofcalibrationstandard, inmL101010105555555Equivalentconcentrationinwater sample,inμg/L10.0020.0040.0080.0160.0310.0630.1250.2500.5001.02.01Ifthe extractvolumeisabout100 μL, the nominal“on-column” concentrationofcalibrationstandardscorrespondstoactualsample concentrationsof0.002 to2.0 μg/L.Figur e 1

. Selec t ed ion c h r o m a togr am of pes tic i des and degr adates in a 0.625- nanogr am

- per

- m ic r o liter

( ng/μL) s t andar d. Num ber s s how n above eac h peak c o r r e s pond to analy t es lis ted in table 5.

A n aly t ical Method 21

### criteria outlined in section 8.2.2. I n addition,

initia lly a d just the ma ss spe c t r o me te r to

ensure that detection at the established

report i n g

- l e vel concent r at i on for each

selected compound can be achieved.

8.2.2 Verify the mass

spect rom e t e r t une pri o r t o each anal y s i s , and

tune if necessary by using the procedure and

standard software supplied by the

manufacturer. Paramete rs in the tuning

software are set to g i ve ±0.15 atomic mass

unit resolution at masses 69, 219, and 414 in

the spe c t r u m of PF TB A. Ma nua lly a d just the

resolution so that the mass 69 ion has 100-

percent relative abundance, mass 219 ion is

20- to 60- percent re lative abundance, and

mass 414 ion is 2- to 7-percent relative

abundance. Check mass assig n ments to

ensure accuracy to ±0.15 atomic mass unit

and that mass peak widths measured at onehalf the peak heig ht are about 0.5±0.15

a t omic ma ss unit. A c o mple te qua ntita tive

r e c a libr a tion with a ll a n a l y t e s is ne e d e d if the

m a ss spect rom e t e r i s re-t uned for m a ss or

resolution.

8.2.3 Mass spectrometer

background interference— L eaks of

at m o spheri c ai r i n t o t h e anal y z er, or t h e

presence of other compounds, mig ht

c o mpr o mise instr u me nt pe r f o r

m a n c e

. Common air backg r ound and contaminant

ions are 18, 28, 32, 40, and 44 atomic mass

units. Check the air backg r ound and print the

result before beg i nning an analy tical batch

(the g r oup of samples whose data are

e v a l ua te d by the qua lity

- c ontr o l sa mple s

associ at ed wi t h t h em ).

9. Calibrat i on

9.1 I n itial c a libration: Eig h t of the

el even cal i b rat i on st andards l i s t e d i n t a bl e 4 are

recom m e nded t o cal i b rat e over t h e ex pect ed

analy tical rang e of about 2 ng /L to 2 μg /L

. The hig h e s t le ve l sta nda r d se le c t e d will

depend on the ex pected upper concentration

rang e of samples.

9.2 I n ject 1 μL of each calibration

st andard i n t o t h e GC / M S accordi n g t o t h e

GC/MS conditions described in section 4.3

and tabulate peak area response and

concent r at i on for each anal y t e and

corresponding internal standard.

I s omers ( ci s -, trans -, Z / E)—Some of the

compounds are resolved into two or more

isomers, depending on the resolution of the

chrom a t o g r aphi c col u m n. I n t h e case of c and t -methy l-3-(2,2-dichloroviny l)-2,2-

dimethy l -(1-cy c lopropane)-carbox y l ate, Eand Z

- dimethomorph, and ci s - and trans

propi conaz o l e , t h e peak area of each i s om er i s

use d to c a libr a te inde pe nde ntly , qua ntita te

, and report each i s om er separat e l y . W e

a ssume tha t the stoc k standards contain equal

amounts of each isomer. Other methods, for

ex ample, method 2060, re port propiconaz o le

rather than the individual ci s - and trans

isome r s, so in situa tions in whic h r e sults f r o m

the different methods are compared, the sum

of the ci s - and trans -isomers should be

calculated for comparison. F o r the py rethroid

compounds cy permethrin and cy fluthrin,

whic h a r e r e solve d into 4 isome r s, the pe a k

areas for each i s om er are sum m e d and used

f o r

c a libr a tion a nd qua ntita tion of the

compound.

9.3 The GC/MS data-processing

software uses standard reg r ession techniques

(Miller and Miller, 1993) to construct

calibration equations and plot calibration

curves for each anal y t e. The i n t e rnal st andard

calibration technique is used, where

reg r essi on of t h e area rat i o s ( A c / A i ) ag ai nst

the c onc e n tr a tion r a tios ( C c / C i ) is de te r mine d

for each anal y t e aft e r anal y s i s of a seri es of

the c a libr a tion sta nda r d s:

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 22

### w h ere A c = area of the quantitation ion for

the selected com pound

or surrog ate com pound;

A i = area of the quantitation ion for

the internal standard;

C

c = concentration of the selected

com pound or surrog ate

com pound, in nanog ram s

per m i croliter; and

C i = concentration of the internal

standard, in nanog ram s per

m i croliter.



### The slope of the calibration curve is

equivalent to the averag e response factor

( RF

c 

### ) of the a n a l y t e r e la tive to the inte r n a l

standard. Z e ro should be included in the

calibration curve, althoug h the curve does not

need to be forced throug h z e ro.

F o r most analy t es, linear or quadratic

reg r ession equations provide the be st f it to the

data. F o r linear re g r ession, the equation

f o llows:

b

C C

m A A

i

i c c 

### 

, (1)

w h ere m = slope of the reg r ession

equation, and

b = intercept of the reg r ession

equation.



### Note tha t the qua ntita tion r a tio in e qua tion 1

c a n be wr itte n a s a ma ss r a tio:

b

M M

m A A

i c

i c 

###  , (2)

w h ere M i 

### = m a ss of the internal standard,

in nanog ram s ; and

M

c 

### = m a ss of the selected

com pound or surrog ate

com pound, in nanog ram s

. 

### The qua ntita tion ion a nd inte r n a l sta nda r d

use d in the c a l c u la tion a r e liste d in ta ble 5.

9.4 Calculate the relative retention

time ( RRT c 

### ) for each selected compound or

surrog a te compound in the calibration

solution, as follows:

RRT c =



### i RT c RT

, (3)

w h ere RT c = uncorrected retention tim e

of the quantitation ion of

the selected com pound or

surrog a te com pound, and

RT i = uncorrected retention tim e

of the quantitation ion of

the internal standard

(acenaphthene- d 10 

### , phenanthrene- d 10 

### , or

chry sene- d 12 

### ).



### 9.5 Ve rific ation of initial c a libration:

Anal y z e a sol u t i on prepared from st andard

m a t e ri al s from a source ot her than those used

to pr e p a r e the initia l c a libr a tion c u r v e

. C a l c ul at e t h e concent r at i on from t h e

cal i b rat i on curve. The cal cul a t e d concent r ation should be within 20 percent of its true

value. This step verifies the validity of the

c a libr a tion sta nda r d ma te r i a l s a nd the

c a libr a tion c u r v e pr ior to sa mple a n a l y s is.

10. Procedure

10.1 W e ighing SPE columns: W e ig h

the SPE columns (±0.0001 g ) and record the

weig ht on the column with waterproof ink.

N O TE: Re c o r d ing the we ig ht on the SPE

c o lumns he lps to de te r mine whe n the c o lumns

are dry after ex traction and dry i ng steps.

A n aly t ical Method 2324 D

by CTable 5.Retention time, quantitation ion, and confirmation ionsforanalytes, surrogates, and internal standards, and selectedionmonitoring group and internal standard foranalytesand surrogates

e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr y[Analytes sortedbyretention time.No.,compoundnumbershown infigure1;Rank,nationalpesticide-userank ofanalyte;P-Code, National WaterInformationSystemparameter code;Approx., approximate;m/z, massper unitcharge;SIM group, selected-ionmonitoringgroup;IS, internalstandardusedfor quantitation:1,Acenaphthene-d10; 2, Phenanthrene-d10; 3,Chrysene-d12; --,not applicable; –,not analyzed]No.RankP-CodeShortnameApprox.retentiontime(min)Quantitationion(m/z)2dmonitoredion(m/z)3rdmonitoredion(m/z)4thmonitoredion(m/z)SIMgroupISInternalStandards131----Acenaphthene-d1017.419162–––--128----Phenanthrene-d1025.484188–––--270----Chrysene-d1240.627240–––--3Surrogates21--99224alpha-HCH-d623.341224222226–15233--99223Diazinon-d10, _ogate26.305183153183–152Analytes11024616303-Trifluoromet_iline5.7841611141421601121002616202-Ethyl-6-meth_iline10.750120121135136213115338775Dichlorvos10.805109185145187241015616334-Chloro-2-met_henol11.27514277107144215112461660O-Ethyl-O-meth_ioate12.652156124128129416106761641Disulfotonsulfoxide13.014212971251534171099616142,5-Dichloroaniline13.100161126163165418104479842c-Methyl-3-(2,_ylate13.409187163165189519104479843t-Methyl-3-(2,_ylate13.65018716316518951101093616273,5-Dichloroaniline15.16216112616316561111032616111,4-Naphthaquinone15.44015810210413061121033616253,4-Dichloroaniline15.99416112616316561141032492951-Naphthol18.281144115116–81151002616152-[2-Ethyl-6-m_panol20.3321621331631939116103461666Phorateoxon21.435171143156170102171013616172-AminoN-isop_amide21.651120119178–1021812804031Cycloate21.822154155215–102Table 5.Retention time, quantitation ion, and confirmation ionsforanalytes, surrogates, and internal standards, and selectedion-monitoring group and internal standard foranalytesand surrogates—Continued

Analytical Method 25No.RankP-CodeShortnameApprox.rententiontime(min)Quantitationion(m/z)2dmonitoredion(m/z)3rdmonitoredion(m/z)4thmonitoredion(m/z)SIMgroupIS198338454Dicrotophos22.979127109193–11220107661671Tefluthrinmet_9364]23.065181141197–1122223061605Sulfotepp23.44432219320214511223105461649Fonofos,oxyge_nalog23.56523093109–112241007616182-Chloro-2,6-d_ilide24.001176147177–122251105616344-Chlorobenzyl_lfone24.12589125127–122262882662Dimethoate24.341938712522912227107661672Tefluthrinmet_2912]25.40191921971411322922004022Terbuthylazine25.7221731382142311423022961604Propetamphos25.895138194222236142311043616293-Phenoxybenzy_cohol25.89520017118120114232123161669Tebupirimphos,_logue26.05024519021726014234101461664Paraoxon-methyl26.520109200230247152357661606Tefluthrin27.12217714117819715236107161642Endosulfanether27.2511702391932771523723161602Tebupirimphos27.41123413715226115238106061652Malaoxon28.841127142173195162391062616372-(4-tert-buty_xanol29.19213513615024816240104961663Paraoxon-ethyl29.240109139220275162416304036Prometryn29.256241184226199162427561596Metalaxyl29.25620622014616016243101661674Terbufos-O-ana_lfone30.44018310913918417244101261636Chlorpyrifos,_nalog30.7331971091691991724522738801Fenthion30.854278109125169172461101616314,4'-Dichlorob_enone30.9231391412502521724722861594Isofenphos32.9422131211852551834813261598Methidathion33.5438593125145193497134362alpha-Endosulfan33.89619515917019719350106761640Disulfotonsulfone34.10521312515315720326 D

by C e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

- 18 Solid-Phase Extr action and G as C h r o matogr aphy/Mass Spectr o metr yTable 5.Retention time, quantitation ion, and confirmation ionsforanalytes, surrogates, and internal standards, and selectedionmonitoring group and internal standard foranalytesand surrogates—ContinuedNo.RankP-CodeShortnameApprox.rententiontime(min)Quantitationion(m/z)2dmonitoredion(m/z)3rdmonitoredion(m/z)4thmonitoredion(m/z)SIMgroupIS5122561592Flumetralin34.4261431451571592035212661591Fenamiphos34.687154153217303213536961603Profenofos35.06820897179206213543061610Tribuphos35.2611691701712022135512161599Myclobutanil35.61017912518120622356113461644Ethionmonoxon35.851171971252152235710661600Oxyfluorfen35.867252195300361223587134357beta-Endosulfan36.49519515917019723359122761647Fenthionsulfoxide36.8841251091532792436013482346Ethion37.429231971251532436111538716Sulprofos37.88715613914032225362107161590Endosulfansulfate38.4402722292372742636310879846cis-Propiconazole38.61317317525926127364112561668Phosmetoxon38.681160161133268273651008616654-(Hydroxymeth_halin38.7162681782692972736611079847trans-Propiconazole38.8881731752592612736712704025Hexazinone39.2261718312817228368112661646Fenamiphossulfoxide40.524304122303–29369105361635Azinphos-methyl-oxon40.52413277160–293719361593Iprodione40.64418718924424624372112661645Fenamiphossulfone40.747320122292–2937312561601Phosmet40.7659377160–2937413161580Bifenthrin41.2091811651661823037510261595Cyhalothrin42.7801811411971993137612961585Cyfluthrin44.3881631651992263237711461586Cypermethrin44.709163165181–3237821179844(E)-Dimethomorph46.3183011651663033337921279845(Z)-Dimethomorph46.5643011651663033338023261607Temephos47.628125203406–343

### 10.2 Precleaning SPE columns:

C o l u m n s are precl eaned pri o r t o use by usi n g

a vacuum pump (manual procedure) or the

Z y mark B e nchMate I I W o rkstation

(automated procedure).

10.2.1 Manual procedure

P r ecl ean t h e S P E col u m n s by

r i nsing with 3 mL of the e l ution solve n t ( e thy l

acet at e). Al l o w t h e sol v ent t o drai n by

g r a v ity , the n c o mple te ly r e move a ll solve n t

f r o m the c o lumn by e ithe r nitr og e n positive

pressure or vacuum. Store the cleaned

columns in 40-mL g l ass vials or in a

desi ccat or at room t e m p erat ure.

10.2.2 Automated procedure

I f

using the B e nchMate I I

W o rkstation, place columns on the rack with

culture tube and fitting (c lean in lots of 100 if

possible). Prog ram the workstation to rinse

t h e l i n es wi t h et hy l acet at e, t h en sequent i a l l y

pum p 3 m L et hy l acet at e t h roug h each

c o lumn a nd dr y

the c o lumn with nitr og e n.

S t ore t h e cl eaned col u m n s at room

temperature in closed 40-mL g l ass vials or in

a desiccator to minimiz e sorption of

c onta mina n ts f r o m the la bor a t or y

environment.

10.3 Precleaning extraction apparatus:

Set up the SPE pumping apparatus. Use a 50-

mL g l ass g r aduated cy linder to contain the

cleaning solutions and prevent contamination

of the inlet tubing . Rinse the Teflon-PF A

tubing and pump with about 50 mL of

deterg ent solution, followed by about 200 mL

of tap water and 50 mL of methanol. Turn on

the pump and adjust the flow rate of the pump

to be twe e n 20 to 25 mL /min by using a

g r aduated cy linder to measure the volume

throug h the SPE column. Ensure that there

a r e no le a k s in a n y of the f itting s . Ke e p the clean inlet tubing of the pump in the clean

g l ass cy linder to avoid contamination of the

tubing while preparing the sample and SPE

column. F o r long er storag e, wrap the tubing

in a l uminum f o il.

I f

usi n g t h e aut o m a t e d Aut o Trace

procedure, rinse the Teflon-PF A tubing and

pump with about 50 mL of cleaning solution

of

isopr opa nol: me thy l e n e c h lor i de : tolue n e

(7:2:1), followed by about 50 mL of methanol

and 100 mL of distilled water.

10.4 SPE column conditioning:

I mmediately before sa mple ex traction, add

3 mL of methanol to the SPE column and

a llow the me tha nol to dr a i n pa r tia lly thr oug h

the c o lumn by g r a v ity . An optiona l L u e r

f l ow- c ontr o l va lve a tta c h e d to the ma le L u e r

f itting of the SPE c o lumn c a n be use d to

control the flow of fluids throug h the SPE

column. Conditioning is needed to solvate

the C- 18 pha se a tta c h e d to the silic a pa r tic le s

in the SPE c o lumn to e n sur e ma x imum

inte r a c tion of the C- 18 pha se with the sa mple

.

N O TE: Do not a llow the c o lumns to g o dr y

onc e c onditioning a nd e quilibr a tion ha ve

started. I f the fluid level drops below the

upper frit of the SPE column, air will enter

the SPE column bed and mig ht prevent

ex posure of the water sample to the SPE C-18

pha se . Ma inta in le ve ls of fluids by adding

a dditiona l f l uid or by c l osing L u e r f

itting s or

flow-control valves. I f the column does g o

dry

, repeat the conditioning process with

methanol followed by water.

10.5 SPE c o lumn e quilibration: Drain

the methanol to the upper frit of the SPE

column. Add 3 to 6 mL of pesticide-g r ade

wa te r a nd a llow the wa te r a nd r e sidua l

methanol to drain by g r avity throug h the

column to the upper frit. About 5 minutes is

requi red for each col u m n vol um e of t h e

me tha nol a nd wa te r to drip throug h the

c o lumn.

A n aly t ical Method 27

### 10.6 Sample preparation: W a ter

sa mple s must ha ve be e n pr e v iously f

ilte r e d

(Sandstrom, 1995). W e ig h the sample and

bottle ( W s ) and record t h e g r oss sam p l e

weig ht (±1 g ) . Add methanol to the sample

equivalent to 1 percen t of the sample volume

(about 9 mL ) as a conditioner, and record the

sa mple we ig ht ( W m ). Add a 100-μL aliquot

of the surrog a te solution (1 ng /μL ; section

7.5) by using a micropipet with a clean

di sposabl e g l ass bore for each sam p l e . (Thi s

step should result in a concentration of 0.1

μg /L f o r

the sur r o g a te s in a 1- L sa mple .) Ca p

a nd g e ntly swir l the sa mple in the bottle to

mix thoroug hly

.

N O TE: Allow sur r o g a te a nd f o r tif ie d

sta nda r d s to c o me to r oom temperature before

adding to samples.

10.7 Sample extraction: W e ig h and

record t h e wei g ht ( W c ) of a 1,000-mL plastic

be a k e r ( o r simila r c onta i ne r ) tha t will be use d

to collect the volume of sample processed

t h roug h t h e col u m n. P l ace t h e i n l e t end of t h e

Teflon-PF A tubing into the sample container,

making sure that the tubing end is positioned

in the lowe st spot of the bottle , a nd tur n on

t h e pum p. Aft e r al l ai r i s di spl aced from t h e

tubing , a tta c h the SPE c o lumn to the outle t

f itting of the pump tubing , a nd c o lle c t the

sample that is pumped throug h the column.

Ensure t h at t h ere are no l eaks or sources of

bubbles in the sy stem. Small bubbles mig ht

form as the sample is pumped throug h the

tubing , but the y will not c a u se a n y pr oble m s

i f

t h ey accum u l a t e i n t h e pum p head. L a rg e

air bubbles are a problem because they can

displace the methanol conditioner in the

column or cause uneven flow.

N O TE: To a void c onta mina ting the sa mple

, do not handle the outside of t h e cl ean sect i on

of tubing that is placed in the sample bottle. W r ap the clean tube in aluminum foil, or

insert into 0.5-mm I D Teflon-PF A tubing

when not i n use. A pi ece of t a pe at t a ched t o

the top of the tubing indicates which section

of the tubing can be handled and which

se c tion is c l e a n a nd will be in c onta c t with the

sa mple

.

Pump the e n tir e sa mple thr oug h the SPE

column at a flow rate of between 20 to 25

mL /min, and turn off the pump when

c o mple te d. Disc onne c t the c o lumn f r o m the

pump sy ste m , a nd r e move r e sidua l inte r s titia l

wa te r with a positive a i r pr e ssur e using a

sy

r i ng e with a L u e r f

itting a nd shor t le ng th of

silicone tubing to connect the L u er fitting to

the open end of the SPE column. W e ig h the

e x tr a c te d wa te r sa mple , a nd r e c o r d the f i na l

weig ht ( W a ) of the sample processed throug h

t h e col u m n and t h e col l ect i on cont ai ner.

Di scard t h e ex t r act ed sam p l e accordi n g t o

appropriate waste-dis posal practices, weig h

the e m pty sa mple bottle , a nd r e c o r d the ta r e

weig ht ( W b ).

10.8 SPE pump cleaning: C l ean t h e

pump and Teflon-PF A tubing with deterg ent

solution, tap water, a nd methanol (or other

solve n t mix tur e ) to pr e p a r e f o r

the ne x t

sa mple

.

10.9 SPE column drying: All SPE

c o lumns a r e dr ie d in the la bor a t or y

pr ior to

elution. Attach a universal adapter to the

larg e, open end of the SPE column. Nex t

a tta c h the a d a p te r to the ma le L u e r f

itting on

the g a s-pressure module of the SPE vacuum

manifold, and then dry the column using a

positive pressure (138 kPa for 20 minutes) of

nitr og e n to r e move a ll inte r s titia l wa te r

. Ve r i f y

tha t a ll wa te r is r e move d f r o m the

column by periodically weig hing the column

a nd c o mpa r ing the we ig ht to the pr e

e x tr a c tion we ig ht. Stor e dr y

c o lumns in a

desiccator (no long er than 7 day s ) until

elution.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 28

### N O TE: Do not dry the column for ex cessive

periods. Pesticides and deg r adates mig ht

evaporate and be rem oved in the g a s phase.

10.10 Elution of compounds: L a bel a

16- by 100-mm culture tube with sample

i d ent i f i cat i on and pl ace i n a hol di ng rack.

Add 100 μL of the PAH internal standard (1

ng /μL ; section 7.4) to the culture tube using a

m i c ropi pet or sy ri ng e. P l ace t h e dri e d S P E

c o lumns in the a ppr opr ia te c u ltur e tube . The

open end of the SPE column should rest on

the e d g e of the c u ltur e tube to ke e p the ma le

L u er end of t h e S P E col u m n rai s ed a few

centimeters above the bottom of the culture

t ube. Add 2 m L of et hy l acet at e t o t h e S P E

c o lumn, a nd a llow the solve n t to dr a i n by

g r avity into the culture tube (about 15–20

minutes). Air pressure (with a 50-mL g l ass

sy

r i ng e ) c a n be use d to g e ntly f

o r c e inte r s titia l

solve n t tha t r e ma ins in the c o lumn into the

vial.

10.11 Evaporation of solvent: P r eheat

the TurboVap evaporator water bath to 30°C,

and adj u st t h e g a s pressure t o 28 kP a. P l ace

culture tubes in the TurboVap evaporator for

about 15 minutes to concentrate the eluant to

about 100 μL under a g e ntle stream of

nitrog en. Periodically check the sample

volumes. At no time should the eluant be

al l o wed t o evaporat e com p l e t e l y because t h i s

will result in loss of compounds.

10.12 Transfer to vials: Use a baked

disposable g l ass Pasteu r pipet to withdraw

eluant, and transfer elua nt to an appropriately

labeled GC vial that c ontains a 400-μL insert

for GC / M S anal y s i s

.

N O TE: A g l a ss sy r i ng e f itte d with a shor t

le ng th of silic one tubing to a tta c h the g l a ss

Pasteur pipet is the preferred equipment for

withdr a w ing e l ua nt into the pipe t. Solve n t

vapors in contact with rubber or latex pipet

bulbs mig ht contaminate the eluant with

pla s tic ize r s. Rinse the culture tube with about 150 to

200 μL of toluene using a sy ring e to dispense

the solve n t, a nd ta ke c a r e not to a llow the tip

of the sy ring e to contact the walls of the

culture tube. I f the tip does contact the culture

tube , r i nse with solve n t. Vor t e x the c u ltur e

t ube, ensuri ng t h e sol v ent reaches t h e hei g ht

of the orig inal 2-mL solvent volume.

Transfer t h e t o l u ene ri nse i n t o t h e GC vi al

insert. A 200- to 300-μL volume of ex tract

should fill about half the volume of the g l ass

inse r t . Ca p the GC via l , a nd r e f r i g e r a te until

GC/MS analy s is is performed.

N O TE: Use of a

pipe t or sque e z e bottle to

rinse the culture tube is not g ood practice

because t h i s m i g ht resul t i n ex cess sol v ent

and require additional evaporation to obtain

the desired final volume of about 200 to

300 μL

.

10.13 Sample analysis and data

evaluation: Ensure that GC/MS conditions

for the analy s is of th e selected compounds in

sam p l e ex t r act s are t h e sam e as t hose used i n

the a n a l y s is of the c a libr a tion sta nda r d s. Pr ior

t o t h e anal y s i s of any sam p l e ex t r act s, ensure

t h at t h e P F TBA m a ss-spect ral perform ance

cri t e ri a have been m e t

, and t h at t h e sel ect edcompound calibration data conform to the

criteria set forth above. I n addition, optimiz e

the sy ste m so tha t the r e por ting le ve l f o r

e a c h

selected compound can be achieved as

described in section 8.2. I n ject 1 μL of the

sam p l e ex t r act , and ac quire data using the

GC/MS conditions described in sections 4.4

and 9.

11. C a lculat ion of R esult s

11.1 Qualitative identification

11.1.1 The observed retention

time of the GC pe a k of the qua ntita tion ion

for the selected compound of interest needs to

be within ±6 seconds of the ex pected

r e te ntion time ( RT ) based on the RRT c

A n aly t ical Method 29

### obta i ne d f r o m the inte r n a l

- s ta nda r d a n a l y s is

( e q. 3) . The e x pe c t e d r e te ntion time is

c a l c u la te d a s f o llows:

, (4) 

### i RT

c RRT RT w h ere RT = expected retention tim e of

the selected com pound

or surrog ate com pound in

the sam p le;

RRT c = relativ e retention tim e of the

selected com pound

or surrog ate com pound

from the calibration

standards; and

RT i = uncorrected retention tim e

of the quantitation ion

of the internal standard in

the sam p le.



### 11.1.2 Mass-spectral ions are

verified for each se lected compound by

comparing the relative integ r ated abundance

values of the three or four sig n ificant ions

monitor e d with the r e la tive inte g r a t e d

abundance values obtained from calibration

solutions de te r mine d by the GC/MS

accordi n g t o procedures previ ousl y g i ven.

The relative ratios of the three or four ions

ne e d to be within ±20 pe r c e n t of the r e la tive

ratios of those obtained on injection of a

1- ng /mL c a libr a tion solution in the a b se nc e

of any obvious interferences.

11.2 Quantitation

11.2.1 Calculate the weig ht of

sa mple pr oc e sse d a s f o llows:

W = ( W a - W c ) x W s - W b

W

m - W b , (5) w h ere W = weig ht of sam p le, in g r am s;

W

a = weig ht of sam p le and collection

container after SPE, in g r am s;

W

c = weig ht of container used to

collect sam p le that passes

throug h SPE colum n, in g r am s;

W

s = w e ig ht of bottle and sam p le,

in g r am s;

W

b = w e ig ht of em pty sam p le bottle,

in g r am s; and

W

m = weig ht of sam p le, m e thanol, and

bottle, in g r am s.



### 11.2.2 I f a selected compound has

pa sse d the a f or e m e n tione d qua lita tive

ide n tif ic a tion c r ite r i a

, the GC/MS da ta

processing software is used to calculate the

tota l ma ss of the a n a l y t e f r o m the c a libr a tion

equations determined in section 9.3. F o r

linear reg r ession, the calib ration equation is as

f o llows:

 



 

 

 b

i A

c A

m

i M

c M



### , (6)

w h ere M

c 

### = m a ss of the selected

com pound or surrog ate

com pound in the sam p le,

i n mi c r o g r a ms ;

M i 

### = m a ss of the internal

standard added to

extract, in m i crog ram s ;

m = slope of reg r ession equation;

A

c 

### = area of the quantitation ion

for the selected com pound or

surrog a te com pound identified

in the sam p le;

A i 

### = area of the quantitation ion

for the internal standard

in the sam p le; and

b = intercept of reg r ession equation.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 30

### The ma ss of the inte r n a l standard added is

c a l c u la te d a s f o llows:

, (7) i V i C i M 

### w h ere M i 

### = m a ss of the internal standard

added to extract, in

mi c r o g r a ms ;

C i 

### = concentration of the internal

standard added to extract, in

nanog ram s per liter; and

V

i 

### = v o lum e of the internal standard

(section 7.4) added to

extract, in m i croliters.



### The concent r at i on of t h e anal y t e i n t h e sam p l e

is c a l c u la te d a s f o llows:

W c M

c C



, (8)

w h ere C

c 

### = concentration of com pound,

in m i crog ram s per liter;

M

c 

### = m a ss of the com pound, in

m i rcrog r am s; and

W = v o lum e of the sam p le, in liters

(assum e 1.0 g = 1.0 m L ).



### 11.2.3 The percent recovery of the

surrog a te compounds is calculated as follows:



### 100     

 

s V

s C c

M

R

, (9)

w h ere R = recov e ry of the surrog ate

com pound, in percent;

M

c 

### = m a ss of the surrog ate in the

sam p le, in m i crog ram s

(from eq. 6); C

s 

### = concentration of the surrog ate

com pound in the surrog a te

standard (section 7.5)

added to the sam p le, in

m i crog ram s per m i croliter; and

V

s 

### = v o lum e of the surrog a te

standard added to the sam p le,

in m i croliters.



### 12. Reporting of Results



### This method was desig n ed for use in

studie s of pe stic ide c onc e n tr a tions in wa te r in

a

va r i e t y of se a s ons a nd la nd- use se tting s f o r

which the best possible information about the

presence and concent r at i on of a pest i c i d e i n

f ilte r e d wa te r is ne e d e d . Conse que ntly

, resul t s are not censored at a l o w report i n g

limit f o r

de te c t e d pe stic ide s . Re sults

c a l c u la te d to be le ss tha n the lowe st

calibration standard (equi valent to 0.002 μg /L

in a water sample for most compounds; table

4) are qual i f i e d as “est i m at ed” (E) t o si g n i f y

t h e l o wer confi d ence i n t h e ex t r apol at ed

concent r at i ons.

C oncent r at i ons of pest i c i d es are

r e por te d to the NWI S da ta ba se a s f o llows. I f

the pe stic ide is not de te c t e d , the r e sult is

r e por te d a s le ss tha n the l a b o ratory

reporting level 

### (L RL ) (for ex ample, <0.002).

I f

the c onc e n tr a tion is within the c a libr a tion

r a ng e

, the r e sult is r e por te d to thr e e

sig n if ic a n t f i g u r e s. I f the c onc e n tr a tion is le ss

tha n the L R L or lowe st c a libr a tion sta nda r d

, the c onc e n tr a tion is r e por te d to two

sig n if ic a n t f i g u r e s, a nd is la be lle d with the

est i m at ed “E” rem a rk t o si g n i f y

t h e l o wer

confi d ence i n t h e ex t r apol at ed concent r at i on.

Simila r l y

, if the c onc e n tr a tion is g r e a t e r tha n

t h e hi g h est concent r at i on st andard, t h e

c onc e n tr a tion is r e por te d to two sig n if ic a n t

fig u res and the " E " code is used. Other

situa tions in whic h the “ E ” qua lif ie r is use d

A n aly t ical Method 31

### i n cl ude when t h e c o nt inuing c a libr a t i on

veri f i cati on 

### (CCV) standard is outside of

ex pect ed l i m i t s and t h e set i s not reanal y z ed,

or

a n y time the a n a l y s t f e e l s the qua ntita tion

m i g h t not be accurat e

.

FINA L METHOD VA LIDA TION



### Ana l y t e s tha t pa sse d both initia l GC/MS

and SPE validation ex peri ments were used in

a dditiona l qua ntita tive va lida tion studie s of

bia s a nd va r i a b ility in thr e e wa te r ty pe s

(pest i c i d e-g r ade wat e r, surface wat e r, and

g r ound water) at two nominal concentrations

(0.10 and 1.0 μg /L ), and at a low

concentration (0.015 to 0.10 μg /L ) to

de te r m ine initia l MDL s . I n a ddition, holding

time ex periments on the SPE column and in

water were conducted.

A reag ent

- wat e r sam p l e , a surface-wat e r

sam p l e col l ect ed from Boul der C r eek near

75 th 

### Street, B oulder, Colo., and a g r oundwa te r sa mple c o lle c t e d f

r o m a monitor we ll

near t h e wast ewat er-t reat m e nt pl ant i n

Denver, Colo., were us ed to test method

perform ance. The reag ent

- wat e r sam p l e was

split into four sets of eig h t subsamples each.

One se t of e i g h t subsa m ple s wa s f o r tif ie d with

0.10 μ g / L of each parent anal y t e, and t h e

other set of eig h t subs a m ple s wa s f o r tif ie d

wi t h 1.0 μ g / L of each parent anal y t e. The

other two sets of eig h t subsamples were

fort i f i e d wi t h 0.10 and 1.0 μ g / L of each

deg r adat e, respect i v el y

. P a rent pest i c i d es

were anal y z ed separat e l y from deg r adat es t o

assess formation of deg r adat es duri n g sam p l e

processing and analy s is.

Each of the surface- and g r ound-water

sa mple s wa s split into 17 1- L subsa m ple s

. One se t of e i g h t subsa m ple s wa s f o r tif ie d with 0.10 μ g / L of each anal y t e, and t h e ot her set of

e i g h t subsa m ple s wa s f o r tif ie d with 1.0 μg /L

of each analy t e. I n addition, unfortified

samples of the surface water and g r ound

wat e r were ex t r act ed and anal y z ed t o

determine backg r ound concentrations of the

pest i c i d es. Al l subsam pl es were anal y z ed at

the Na tiona l Wa te r Qua lity L a bor a t or y

using

one GC/MS. Ea c h sa mple se t wa s f o r tif ie d,

ex t r act ed, and anal y z ed on di fferent day s

during J une–J uly 1999, so comparison of

different matrices and concentrations includes

bi as from day

- t o -day vari at i on. The surfaceand g r ound-water sample s did not require

correction for backg r ound concentrations of

anal y t es because no anal y t es were det ect ed i n

e ithe r unf or tif ie d sa mple . Summa r i e s of

r e c ove r y

a nd va r i a b ility of the a n a l y s e s a r e

provided in tables 6 throug h 9.

The percent recovery of t h e anal y t es i s

c a l c u la te d a s f o llows:

R

= 

### 100 ) (

n u s



### C C C

, (10)

w h ere R = recov e ry of the pesticide or

pesticide deg r adate, in percent;

C

s = m easured concentration in the

fortified sam p le, in m i crog ram s

per liter;

C

u = m easured concentration in the

unfortified sam p le, in m i crog ram s

per liter (use 0 for reag ent- w a ter

sam p le); and

C

n = nom inal (theoretical) concentration

increase that results from fortify i ng

the sam p le, in m i crog ram s per liter.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 32Final Method Validation 33Table 6.Bias and variability data from eight reagent-water samples fortified with parent pesticide analytes at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations[Analytes are separated into parent pesticides and degradates andsorted by remark code and then by rank. Presence of degradate indicates breakdown ofcorresponding parent pesticide during sample preparation or analysis. Recovery of degradate based on expected concentration ofparent pesticide. Rank, nationalapplication and use rank of pesticide; P-Code, National Water Information System parameter code; μg/L, microgram per liter; F-pseu, F-pseudosigma (interquartilerange/1.349); Rel F-pseu, relative F-pseudosigma; –, not applicable; --, not analyzed; E, estimated remark code]High LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)RemarkcodeParent pesticides63 04036 Prometryn 0.950 0.0379 95.0 4.0 0.0838 0.0034 83.8 4.1 –69 61603 Profenofos 0.680 0.0184 68.0 2.7 0.0671 0.0035 67.1 5.2 –71 34362alpha-Endosulfan 0.799 0.0123 79.9 1.5 0.0799 0.0026 79.9 3.2 –75 61596 Metalaxyl 0.934 0.0426 93.4 4.6 0.0858 0.0033 85.8 3.9 –106 61600 Oxyfluorfen 0.538 0.0485 53.8 9.0 0.0527 0.0042 52.7 7.9 –108 79846cis-Propiconazole 0.673 0.0127 67.3 1.9 0.0696 0.0020 69.6 2.8 –110 79847trans-Propiconazole 0.714 0.0085 71.4 1.2 0.0697 0.0034 69.7 4.8 –121 61599 Myclobutanil 0.784 0.0136 78.4 1.7 0.0663 0.0033 66.3 5.0 –126 61591 Fenamiphos 0.572 0.0192 57.2 3.4 0.0724 0.0023 72.4 3.1 –127 04025 Hexazinone 0.578 0.0261 57.8 4.5 0.0515 0.0013 51.5 2.6 –128 04031 Cycloate 0.829 0.0155 82.9 1.9 0.0803 0.0029 80.3 3.7 –132 61598 Methidathion 0.795 0.018979.5 2.4 0.0716 0.0018 71.6 2.5 –134 82346 Ethion 0.627 0.0344 62.7 5.5 0.0503 0.0015 50.3 3.0 –211 79844 (E)-Dimethomorph 0.698 0.0119 69.8 1.7 0.0811 0.0044 81.1 5.4 –212 79845 (Z)-Dimethomorph 0.683 0.0136 68.3 2.0 0.0824 0.0032 82.4 3.8 –220 04022 Terbuthylazine 1.052 0.0568 105.2 5.4 0.1000 0.0044 100.0 4.4 –225 61592 Flumetralin 0.534 0.0484 53.4 9.1 0.0520 0.0036 52.0 7.0 –227 38801 Fenthion 0.988 0.0337 98.8 3.4 0.0965 0.0051 96.5 5.3 –228 61594 Isofenphos 0.849 0.0405 84.9 4.8 0.0759 0.0035 75.9 4.6 –229 61604 Propetamphos 0.861 0.0524 86.1 6.1 0.0828 0.0025 82.8 3.0 –231 61602 Tebupirimphos 0.844 0.044884.4 5.3 0.0741 0.0033 74.1 4.5 –28 82662 Dimethoate 0.292 0.0416 29.2 14.3 0.0515 0.0120 51.5 23.3 E30 61610 Tribuphos 0.400 0.0468 40.0 11.7 0.0328 0.0038 32.8 11.7 E34 Determination of Moderate-Use Pesticides and Selected Degradates in Water

by C-18 Solid-Phase Extraction and Gas Chromatography/Mass SpectrometryTable 6.Bias and variability data from eight reagent-water samples fortified with parent pesticide analytes at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode71 34357beta-Endosulfan 0.815 0.0194 81.5 2.4 0.0857 0.0033 85.7 3.8 E76 61606 Tefluthrin 0.215 0.0367 21.5 17.1 0.0167 0.0022 16.7 13.4 E83 38454 Dicrotophos 0.135 0.0249 13.5 18.5 0.0147 0.0035 14.7 23.8 E93 61593 Iprodione 0.608 0.0265 60.8 4.4 0.0455 0.0024 45.5 5.4 E102 61595 Cyhalothrin 0.194 0.0304 19.4 15.7 0.0091 0.0011 9.1 12.3 E114 61586 Cypermethrin 0.270 0.033727.0 12.5 0.0307 0.0066 30.7 21.6 E115 38716 Sulprofos 0.719 0.0330 71.9 4.6 0.0596 0.0045 59.6 7.5 E125 61601 Phosmet10.586 0.0420 58.6 7.2 -- -- -- -- E129 61585 Cyfluthrin 0.265 0.0330 26.5 12.5 0.0310 0.0061 31.0 19.7 E131 61580 Bifenthrin 0.262 0.0555 26.2 21.2 0.0132 0.0023 13.2 17.2 E230 61605 Sulfotepp 0.960 0.0293 96.0 3.0 0.0851 0.0023 85.1 2.8 E232 61607 Temephos 0.283 0.0499 28.3 17.7 0.0371 0.0040 37.1 10.7 EDegradates1002 61615 2-[2-Ethyl-6-m_panol -- -- -- -- -- -- -- -- –1007 61618 2-Chloro-2,6-d_ilide -- -- -- -- -- -- -- -- –1008 61665 4-(Hydroxymeth_halin -- -- -- -- -- -- -- -- –1016 61674 Terbufos-O-ana_lfone -- -- -- -- -- -- -- -- –1033 61625 3,4-Dichloroaniline -- -- -- -- -- -- -- -- –1043 61629 3-Phenoxybenzy_cohol -- -- -- -- -- -- -- -- –1044 79842c-Methyl-3-(2,_ylate 0.015 0.0016 1.5 10.6 0.0057 0.0009 5.7 16.3 –1044 79843t-Methyl-3-(2,_ylate 0.010 0.0007 1.0 7.5 0.0070 0.0003 7.0 3.7 –1049 61663 Paraoxon-ethyl -- -- -- -- -- -- -- -- –1060 61652 Malaoxon -- -- -- -- -- -- -- -- –1062 61637 2-(4-tert-buty_xanol -- -- -- -- -- -- -- -- –1067 61640 Disulfoton sulfone -- -- -- -- -- -- -- -- –1067 61641 Disulfoton sulfoxide -- -- -- -- -- -- -- -- –1071 61590 Endosulfan sulfate -- -- -- -- -- -- -- -- –1071 61642 Endosulfan ether 0.007 0.0011 0.7 15.8 0.0033 0.0007 3.3 21.1 –1076 61672 Tefluthrin met_2912] -- -- -- -- -- -- -- -- –Final Method Validation 35Table 6.Bias and variability data from eight reagent-water samples fortified with parent pesticide analytes at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode1093 61627 3,5-Dichloroaniline -- -- -- -- -- -- -- -- –1099 61614 2,5-Dichloroaniline -- -- -- -- -- -- -- -- –1124 61660 O-Ethyl-O-meth_ioate -- -- -- -- 0.0029 0.0003 2.9 10.0 –1126 61645 Fenamiphos sulfone -- -- -- -- -- -- -- -- –1231 61669 Tebupirimphos,_logue -- -- -- -- -- -- -- -- –1002 61620 2-Ethyl-6-meth_iline -- -- -- -- -- -- -- -- E1012 61636 Chlorpyrifos, _nalog -- -- -- -- -- -- -- -- E1013 61617 2-Amino-N-isop_amide -- -- -- -- -- -- -- -- E1014 61664 Paraoxon-methyl -- -- -- -- -- -- -- -- E1015 61633 4-Chloro-2-met_henol -- -- -- -- -- -- -- -- E1024 61630 3-Trifluoromet_iline -- -- -- -- -- -- -- -- E1032 49295 1-Naphthol -- -- -- -- -- -- -- -- E1032 61611 1,4-Naphthaquinone -- -- -- -- -- -- E1034 61666 Phorate oxon -- -- -- -- -- -- -- -- E1053 61635 Azinphos-methyl-oxon -- -- -- -- -- -- -- -- E1054 61649 Fonofos, oxyge_nalog -- -- -- -- -- -- -- -- E1076 61671 Tefluthrin met_9364] -- -- -- -- -- -- -- -- E1101 61631 4,4'-Dichlorob_enone -- -- -- -- -- -- -- -- E1105 61634 4-Chlorobenzyl_lfone -- -- -- -- -- -- -- -- E1125 61668 Phosmet oxon -- -- -- -- -- -- -- -- E1126 61646 Fenamiphos sulfoxide -- -- -- -- -- -- -- -- E1134 61644 Ethion monoxon -- -- -- -- 0.0101 0.0009 10.1 9.3 E1153 38775 Dichlorvos -- -- -- -- -- -- -- -- E1227 61647 Fenthion sulfoxide 0.014 0.0009 1.4 6.2 0.0048 0.0011 4.8 22.8 ESurrogates-- -- -- -- -- -- -- -- –99223 Diazinon-d10, _ogate 0.755 0.0169 75.5 2.2 0.0996 0.0021 99.6 2.1 –99224alpha-HCH-d6, _ogate 0.953 0.0457 95.3 4.8 0.0859 0.0033 85.9 3.8 –1Phosmet was not included in low concentration recovery experiments.36 Determination of Moderate-Use Pesticides and Selected Degradates in Water

by C-18 Solid-Phase Extraction and Gas Chromatography/Mass SpectrometryTable 7.Bias and variability data from eight reagent-water samples fortified with degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations[Analytes are sorted by remark code and then by rank. Rank, national application and use rank of pesticide; P-Code, National Water Information System parametercode; Median conc., median observed concentration; μg/L, microgram per liter; F-pseu, F-pseudosigma (interquartile range/1.349); Rel F-pseu, relativeF-pseudosigma; –, not applicable; E, estimated remark code]High LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)RemarkcodeDegradates1002 61615 2-[2-Ethyl-6-m_panol 1.009 0.0988 100.9 9.8 0.0808 0.0053 80.8 6.6 –1007 61618 2-Chloro-2,6-d_ilide 1.054 0.0439 105.4 4.2 0.0938 0.0018 93.8 1.9 –1008 61665 4-(Hydroxymeth_halin 1.0510.1364 105.1 13.0 0.0834 0.0077 83.4 9.3 –1016 61674 Terbufos-O-ana_lfone 0.9540.0797 95.4 8.4 0.0774 0.0071 77.4 9.1 –1033 61625 3,4-Dichloroaniline 0.947 0.1165 94.7 12.3 0.0863 0.0084 86.3 9.7 –1043 61629 3-Phenoxybenzy_cohol 1.1320.0972 113.2 8.6 0.0718 0.0024 71.8 3.3 –1044 79842c-Methyl-3-(2,_ylate 0.862 0.0574 86.2 6.7 0.0846 0.0028 84.6 3.3 –1044 79843t-Methyl-3-(2,_ylate 0.927 0.0512 92.7 5.5 0.0891 0.0040 89.1 4.5 –1049 61663 Paraoxon-ethyl11.198 0.3089 119.8 25.8 0.0872 0.0028 87.2 3.3 –1060 61652 Malaoxon 1.009 0.0727 100.9 7.2 0.0919 0.0052 91.9 5.7 –1062 61637 2-(4-tert-buty_xanol 1.0600.0547 106.0 5.2 0.0800 0.0057 80.0 7.1 –1067 61640 Disulfoton sulfone 0.923 0.0734 92.3 8.0 0.0783 0.0033 78.3 4.2 –1071 61590 Endosulfan sulfate10.865 0.0209 86.5 2.4 0.0919 0.0032 91.9 3.5 –1071 61642 Endosulfan ether 1.088 0.0430 108.8 4.0 0.1018 0.0027 101.8 2.6 –1076 61672 Tefluthrin met_2912] 0.653 0.0898 65.3 13.7 0.0601 0.0024 60.1 4.0 –1093 61627 3,5-Dichloroaniline 1.081 0.1030 108.1 9.5 0.0965 0.0064 96.5 6.6 –1099 61614 2,5-Dichloroaniline 0.986 0.1050 98.6 10.7 0.0856 0.0050 85.6 5.9 –1124 61660 O-Ethyl-O-meth_ioate 0.9540.0856 95.4 9.0 0.0852 0.0047 85.2 5.6 –1126 61645 Fenamiphos sulfone 0.861 0.1068 86.1 12.4 0.0637 0.0053 63.7 8.3 –1231 61669 Tebupirimphos,_logue 0.900 0.0719 90.0 8.0 0.0722 0.0025 72.2 3.5 –1002 61620 2-Ethyl-6-meth_iline 1.090 0.0788 109.0 7.2 0.1014 0.0019 101.4 1.9 E1012 61636 Chlorpyrifos, _nalog 0.282 0.0466 28.2 16.5 0.0176 0.0051 17.6 28.7 E1013 61617 2-Amino-N-isop_amide 0.675 0.0681 67.5 10.1 0.0589 0.0088 58.9 15.0 E1014 61664 Paraoxon-methyl 0.852 0.090985.2 10.7 0.0695 0.0022 69.5 3.2 EFinal Method Validation 37Table 7.Bias and variability data from eight reagent-water samples fortified with degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode1015 61633 4-Chloro-2-met_henol 0.817 0.1319 81.7 16.1 0.0721 0.0098 72.1 13.7 E1024 61630 3-Trifluoromet_iline 0.451 0.1181 45.1 26.2 0.0407 0.0030 40.7 7.5 E1032 49295 1-Naphthol 0.136 0.0542 13.6 39.9 0.0255 0.0103 25.5 40.4 E1032 61611 1,4-Naphthaquinone 0.211 0.1189 21.1 56.2 0.0335 0.0104 33.5 31.0 E1034 61666 Phorate oxon 0.879 0.134187.9 15.2 0.0727 0.0059 72.7 8.1 E1053 61635 Azinphos-methyl-oxon 0.919 0.0993 91.9 10.8 0.0575 0.0115 57.5 19.9 E1054 61649 Fonofos, oxyge_nalog 0.839 0.0861 83.9 10.3 0.0709 0.0019 70.9 2.7 E1067 61641 Disulfoton sulfoxide 1.417 0.0640 141.7 4.5 0.1318 0.0070 131.8 5.3 E1076 61671 Tefluthrin met_9364] 0.491 0.0892 49.1 18.2 0.0451 0.0034 45.1 7.6 E1101 61631 4,4'-Dichlorob_enone 0.900 0.0763 90.0 8.5 0.0697 0.0026 69.7 3.8 E1105 61634 4-Chlorobenzyl_lfone 0.6810.0671 68.1 9.8 0.0654 0.0073 65.4 11.2 E1125 61668 Phosmet oxon 0.771 0.059377.1 7.7 0.0294 0.0102 29.4 34.8 E1126 61646 Fenamiphos sulfoxide 0.197 0.0277 19.7 14.0 0.0251 0.0029 25.1 11.4 E1134 61644 Ethion monoxon 0.645 0.0837 64.5 13.0 0.0452 0.0022 45.2 4.8 E1153 38775 Dichlorvos10.673 0.0752 67.3 11.2 0.0803 0.0041 80.3 5.1 E1227 61647 Fenthion sulfoxide 0.823 0.1058 82.3 12.9 0.0785 0.0035 78.5 4.5 ESurrogates99223 Diazinon-d10, _ogate 1.472 0.0466 147.2 3.2 0.1083 0.0051 108.3 4.7 –99224alpha-HCH-d6, _ogate 0.613 0.0487 61.3 7.9 0.0596 0.0028 59.6 4.7 –1Analyte was determined in parent fortification mixture.38 Determination of Moderate-Use Pesticides and Selected Degradates in Water

by C-18 Solid-Phase Extraction and Gas Chromatography/Mass SpectrometryTable 8.Bias and variability data from eight surface-water samples fortified with parent pesticides and degradates at high (1.0 microgram perliter) and low (0.1 microgram per liter) concentrations[Analytes are separated into parent pesticides and degradate pesticides and sorted by remark code and then by rank. Surface water collected from BoulderCreek at 75th Street on June 3, 1999. Analysis of unfortified sample indicated no analytes greater than reporting levels. Rank, national application and userank of pesticide; P-Code, National Water Information System parameter code; F-pseu, F-pseudosigma (interquartile range/1.349);Rel F-pseu, relative F-pseudosigma; μg/L, microgram per liter; –, not applicable; --, not analyzed; E, estimated remark code]High LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)RemarkcodeParent pesticides63 04036 Prometryn 0.410 0.3697 41.090.2 0.0786 0.0040 78.6 4.0 –69 61603 Profenofos 0.768 0.0358 76.8 4.7 0.1041 0.0063 104.1 6.3 –71 34362alpha-Endosulfan 0.796 0.0199 79.6 2.5 0.0962 0.0117 96.2 11.7 –75 61596 Metalaxyl 0.952 0.0414 95.24.3 0.0910 0.0040 91.0 4.0 –106 61600 Oxyfluorfen 0.675 0.0839 67.5 12.4 0.0927 0.0086 92.7 8.6 –108 79846cis-Propiconazole 0.239 0.2567 23.9 107.4 0.1063 0.0068 106.3 6.8 –110 79847trans-Propiconazole 0.470 0.2901 47.0 61.7 0.1089 0.0047 108.9 4.7 –121 61599 Myclobutanil 0.798 0.0358 79.8 4.5 0.1034 0.0031 103.4 3.1 –126 61591 Fenamiphos 0.796 0.0404 79.6 5.1 0.1024 0.0051 102.4 5.1 –127 04025 Hexazinone 0.615 0.0818 61.5 13.3 0.0981 0.0030 98.1 3.0 –128 04031 Cycloate 0.844 0.0598 84.47.1 0.1045 0.0069 104.5 6.9 –132 61598 Methidathion 0.849 0.0496 84.9 5.8 0.1102 0.0038 110.2 3.8 –134 82346 Ethion 0.496 0.0193 49.6 3.9 0.0800 0.0045 80.0 4.5 –211 79844 (E)-Dimethomorph 0.846 0.041284.6 4.9 0.1026 0.0043 102.6 4.3 –212 79845 (Z)-Dimethomorph 0.838 0.024883.8 3.0 0.1091 0.0060 109.1 6.0 –220 04022 Terbuthylazine1-- -- -- -- -- -- -- -- –225 61592 Flumetralin 0.499 0.0939 49.9 18.8 0.0918 0.0056 91.8 5.6 –227 38801 Fenthion 0.934 0.0501 93.45.4 0.0697 0.0042 69.7 4.2 –228 61594 Isofenphos 0.883 0.0426 88.3 4.8 0.0921 0.0043 92.1 4.3 –229 61604 Propetamphos 0.863 0.0396 86.3 4.6 0.0966 0.0072 96.6 7.2 –231 61602 Tebupirimphos 0.767 0.0219 76.7 2.9 0.0802 0.0049 80.2 4.9 –28 82662 Dimethoate 0.450 0.0715 45.0 15.9 0.0413 0.0011 41.3 1.1 E30 61610 Tribuphos 0.451 0.0265 45.1 5.9 0.0825 0.0041 82.5 4.1 E71 34357beta-Endosulfan 0.703 0.0362 70.3 5.1 0.1047 0.0071 104.7 7.1 E76 61606 Tefluthrin 0.173 0.0135 17.3 7.8 0.0414 0.0038 41.4 3.8 EFinal Method Validation 39Table 8.Bias and variability data from eight surface-water samples fortified with parent pesticides and degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode83 38454 Dicrotophos 0.164 0.0548 16.4 33.5 0.0338 0.0026 33.8 2.6 E93 61593 Iprodione 0.690 0.0239 69.03.5 0.1116 0.0117 111.6 11.7 E102 61595 Cyhalothrin 0.160 0.0170 16.0 10.6 0.0454 0.0037 45.4 3.7 E114 61586 Cypermethrin 0.223 0.0195 22.3 8.7 0.0787 0.0093 78.7 9.3 E115 38716 Sulprofos 0.476 0.0343 47.6 7.2 0.0792 0.0046 79.2 4.6 E125 61601 Phosmet 0.622 0.0490 62.27.9 0.1058 0.0035 105.8 3.5 E129 61585 Cyfluthrin 0.214 0.0092 21.4 4.3 0.0773 0.0026 77.3 2.6 E131 61580 Bifenthrin 0.144 0.0108 14.4 7.5 0.0506 0.0041 50.6 4.1 E230 61605 Sulfotepp 0.734 0.0380 73.45.2 0.0651 0.0053 65.1 5.3 E232 61607 Temephos 0.217 0.0146 21.7 6.7 0.1425 0.0097 142.5 9.7 EDegradates1002 61615 2-[2-Ethyl-6-m_panol 0.871 0.0335 87.1 3.8 0.1055 0.0087 105.5 8.7 –1007 61618 2-Chloro-2,6-d_ilide 0.903 0.0638 90.3 7.1 0.0980 0.0052 98.0 5.2 –1008 61665 4-(Hydroxymeth_halin 0.993 0.0161 99.3 1.6 0.1329 0.0097 132.9 9.7 –1016 61674 Terbufos-O-ana_lfone 0.861 0.0410 86.1 4.8 0.0923 0.0053 92.3 5.3 –1033 61625 3,4-Dichloroaniline 0.926 0.035992.6 3.9 0.0765 0.0023 76.5 2.3 –1043 61629 3-Phenoxybenzy_cohol 0.827 0.0430 82.7 5.2 0.0896 0.0073 89.6 7.3 –1044 79842c-Methyl-3-(2,_ylate 0.788 0.0185 78.8 2.4 0.0955 0.0054 95.5 5.4 –1044 79843t-Methyl-3-(2,_ylate 0.805 0.0239 80.5 3.0 0.0905 0.0074 90.5 7.4 –1049 61663 Paraoxon-ethyl 0.922 0.033792.2 3.7 0.1012 0.0074 101.2 7.4 –1060 61652 Malaoxon 0.873 0.0345 87.33.9 0.1064 0.0071 106.4 7.1 –1062 61637 2-(4-tert-buty_xanol 0.864 0.0433 86.4 5.0 0.1042 0.0087 104.2 8.7 –1067 61640 Disulfoton sulfone 0.869 0.0416 86.9 4.8 0.1045 0.0035 104.5 3.5 –1071 61590 Endosulfan sulfate 0.761 0.0237 76.1 3.1 0.0915 0.0079 91.5 7.9 –1071 61642 Endosulfan ether 0.826 0.0264 82.6 3.2 0.0805 0.0052 80.5 5.2 –1076 61672 Tefluthrin met_2912] 0.327 0.0363 32.7 11.1 0.0675 0.0068 67.5 6.8 –1093 61627 3,5-Dichloroaniline 0.923 0.027692.3 3.0 0.0913 0.0051 91.3 5.1 –1099 61614 2,5-Dichloroaniline 0.841 0.015484.1 1.8 0.0819 0.0043 81.9 4.3 –1124 61660 O-Ethyl-O-meth_ioate 0.856 0.0298 85.6 3.5 0.0978 0.0058 97.8 5.8 –1126 61645 Fenamiphos sulfone 0.788 0.0353 78.8 4.5 0.0955 0.0047 95.5 4.7 –40 Determination of Moderate-Use Pesticides and Selected Degradates in Water

by C-18 Solid-Phase Extraction and Gas Chromatography/Mass SpectrometryTable 8.Bias and variability data from eight surface-water samples fortified with parent pesticides and degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode1231 61669 Tebupirimphos,_logue 0.832 0.0376 83.2 4.5 0.0766 0.0051 76.6 5.1 –1002 61620 2-Ethyl-6-meth_iline 0.786 0.0422 78.6 5.4 0.1170 0.0049 117.0 4.9 E1012 61636 Chlorpyrifos, _nalog 0.780 0.0296 78.0 3.8 0.0496 0.0032 49.6 3.2 E1013 61617 2-Amino-N-isop_amide 0.689 0.0878 68.9 12.8 0.0476 0.0019 47.6 1.9 E1014 61664 Paraoxon-methyl 0.884 0.050188.4 5.7 0.1047 0.0032 104.7 3.2 E1015 61633 4-Chloro-2-met_henol 0.814 0.0515 81.4 6.3 0.0693 0.0034 69.3 3.4 E1024 61630 3-Trifluoromet_iline 0.733 0.0928 73.3 12.7 0.0432 0.0011 43.2 1.1 E1032 49295 1-Naphthol1-- -- -- -- -- -- -- -- E1032 61611 1,4-Naphthaquinone1-- -- -- -- 0.0733 0.0042 73.3 4.2 E1034 61666 Phorate oxon 0.862 0.0463 86.2 5.4 0.0848 0.0049 84.8 4.9 E1053 61635 Azinphos-methyl-oxon 0.875 0.0470 87.5 5.4 0.1316 0.0004 131.6 0.4 E1054 61649 Fonofos, oxyge_nalog 0.774 0.0463 77.4 6.0 0.0922 0.0065 92.2 6.5 E1067 61641 Disulfoton sulfoxide 0.966 0.0507 96.6 5.3 0.1051 0.0069 105.1 6.9 E1076 61671 Tefluthrin met_9364] 0.217 0.0143 21.7 6.6 0.0404 0.0052 40.4 5.2 E1101 61631 4,4'-Dichlorob_enone 0.858 0.0305 85.8 3.6 0.1035 0.0079 103.5 7.9 E1105 61634 4-Chlorobenzyl_lfone 0.684 0.0919 68.4 13.4 0.0538 0.0040 53.8 4.0 E1125 61668 Phosmet oxon 0.601 0.0504 60.1 8.4 0.1188 0.0021 118.8 2.1 E1126 61646 Fenamiphos sulfoxide1-- -- -- -- 0.0552 0.0120 55.2 12.0 E1134 61644 Ethion monoxon 0.771 0.0296 77.1 3.8 0.1007 0.0045 100.7 4.5 E1153 38775 Dichlorvos 0.638 0.0349 63.8 5.5 0.0444 0.0023 44.4 2.3 E1227 61647 Fenthion sulfoxide 0.775 0.0336 77.5 4.3 0.0965 0.0038 96.5 3.8 ESurrogates99223 Diazinond10, _ogate 1.209 0.0290 120.9 2.4 0.0781 0.0023 78.1 2.3 –99224alpha-HCHd6, _ogate 0.865 0.1916 86.5 22.1 0.0980 0.0047 98.0 4.7 –1Terbuthylazine, 1-naphthol, 1,4-naphthaquinone, and fenamiphos sulfoxide not included in fortification mixture.Final Method Validation 41Table 9.Bias and variability data from eight ground-water samples fortified with parent pesticides and degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations[Analytes are separated into parent pesticides and degradate pesticides and sorted by remark code and then by rank. Ground water collected in northeastDenver on June 3, 1999. Analysis of unfortified sample indicated no analytes greater than reporting limits. Rank, national application and use rank ofpesticide; P-Code, National Water Information System parameter code; μg/L, microgram per liter; F-pseu, F-pseudosigma (interquartile range/1.349); Rel Fpseu, relative F-pseudosigma; –, not applicable; --, not analyzed; E, estimated remark code]High LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)RemarkcodeParent pesticides63 04036 Prometryn 1.010 0.031 101.03.1 0.0821 0.0057 82.1 6.9 –69 61603 Profenofos 0.782 0.037 78.2 4.8 0.0926 0.0086 92.6 9.3 –71 34362alpha-Endosulfan 0.818 0.034 81.8 4.2 0.0951 0.0056 95.1 5.9 –75 61596 Metalaxyl 0.952 0.027 95.22.9 0.0910 0.0047 91.0 5.2 –106 61600 Oxyfluorfen 0.849 0.038 84.9 4.5 0.0917 0.0051 91.7 5.6 –108 79846cis-Propiconazole 0.604 0.016 60.4 2.6 0.1144 0.0076 114.4 6.7 –110 79847trans-Propiconazole 0.877 0.034 87.7 3.8 0.1102 0.0109 110.2 9.9 –121 61599 Myclobutanil 0.881 0.029 88.1 3.3 0.1069 0.0040 106.9 3.7 –126 61591 Fenamiphos 0.771 0.024 77.1 3.2 0.1048 0.0098 104.8 9.4 –127 04025 Hexazinone 0.645 0.026 64.5 4.1 0.0902 0.0103 90.2 11.4 –128 04031 Cycloate 0.942 0.070 94.27.4 0.0950 0.0056 95.0 5.9 –132 61598 Methidathion 0.848 0.012 84.8 1.5 0.1033 0.0055 103.3 5.3 –134 82346 Ethion 0.637 0.047 63.7 7.3 0.0850 0.0042 85.0 4.9 –211 79844 (E)-Dimethomorph 0.851 0.03185.1 3.6 0.0958 0.0042 95.8 4.3 –212 79845 (Z)-Dimethomorph 0.844 0.03284.4 3.8 0.1006 0.0041 100.6 4.1 –220 04022 Terbuthylazine1-- -- -- -- -- -- -- -- –225 61592 Flumetralin 0.973 0.092 97.3 9.5 0.0949 0.0062 94.9 6.6 –227 38801 Fenthion 0.993 0.022 99.32.2 0.0789 0.0050 78.9 6.3 –228 61594 Isofenphos 0.948 0.033 94.8 3.4 0.0918 0.0043 91.8 4.7 –229 61604 Propetamphos 0.876 0.032 87.6 3.7 0.0908 0.0040 90.8 4.4 –231 61602 Tebupirimphos 0.841 0.025 84.1 3.0 0.0787 0.0050 78.7 6.3 –28 82662 Dimethoate 0.328 0.007 32.8 2.1 0.0447 0.0033 44.7 7.4 E30 61610 Tribuphos 0.541 0.057 54.1 10.5 0.0842 0.0089 84.2 10.6 E71 34357beta-Endosulfan 0.775 0.043 77.5 5.5 0.0982 0.0125 98.2 12.7 E76 61606 Tefluthrin 0.339 0.041 33.9 12.2 0.0461 0.0051 46.1 11.1 E42 Determination of Moderate-Use Pesticides and Selected Degradates in Water

by C-18 Solid-Phase Extraction and Gas Chromatography/Mass SpectrometryTable 9.Bias and variability data from eight ground-water samples fortified with parent pesticides and degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode83 38454 Dicrotophos 0.147 0.011 14.7 7.4 0.0186 0.0052 18.6 28.3 E93 61593 Iprodione 0.708 0.049 70.86.9 0.1051 0.0128 105.1 12.2 E102 61595 Cyhalothrin 0.361 0.034 36.1 9.4 0.0479 0.0050 47.9 10.5 E114 61586 Cypermethrin 0.435 0.033 43.5 7.6 0.0767 0.0067 76.7 8.8 E115 38716 Sulprofos 0.622 0.047 62.2 7.5 0.1014 0.0079 101.4 7.8 E125 61601 Phosmet 0.771 0.035 77.14.6 0.0869 0.0074 86.9 8.6 E129 61585 Cyfluthrin 0.415 0.035 41.5 8.5 0.0749 0.0032 74.9 4.3 E131 61580 Bifenthrin 0.373 0.041 37.3 11.0 0.0575 0.0055 57.5 9.6 E230 61605 Sulfotepp 0.844 0.019 84.42.3 0.0783 0.0067 78.3 8.5 E232 61607 Temephos 0.471 0.026 47.1 5.5 0.1296 0.0101 129.6 7.8 EDegradates1002 61615 2-[2-Ethyl-6-m_panol 0.838 0.016 83.8 2.0 0.1030 0.0049 103.0 4.8 –1007 61618 2-Chloro-2,6-d_ilide 0.837 0.072 83.7 8.6 0.0934 0.0067 93.4 7.1 –1008 61665 4-(Hydroxymeth_halin 0.993 0.010 99.3 1.0 0.1159 0.0055 115.9 4.8 –1016 61674 Terbufos-O-ana_lfone 0.820 0.016 82.0 1.9 0.0879 0.0108 87.9 12.3 –1033 61625 3,4-Dichloroaniline 0.836 0.02083.6 2.4 0.0853 0.0046 85.3 5.4 –1043 61629 3-Phenoxybenzy_cohol 0.804 0.019 80.4 2.3 0.0848 0.0059 84.8 6.9 –1044 79842c-Methyl-3-(2,_ylate 0.834 0.017 83.4 2.0 0.0893 0.0063 89.3 7.1 –1044 79843t-Methyl-3-(2,_ylate 0.832 0.018 83.2 2.2 0.0891 0.0078 89.1 8.7 –1049 61663 Paraoxon-ethyl 0.908 0.03390.8 3.7 0.0894 0.0114 89.4 12.8 –1060 61652 Malaoxon 0.809 0.023 80.92.9 0.0933 0.0089 93.3 9.5 –1062 61637 2-(4-tert-buty_xanol 0.875 0.027 87.5 3.1 0.0915 0.0081 91.5 8.9 –1067 61640 Disulfoton sulfone 0.850 0.024 85.0 2.8 0.1059 0.0062 105.9 5.8 –1071 61590 Endosulfan sulfate 0.809 0.036 80.9 4.4 0.0892 0.0045 89.2 5.1 –1071 61642 Endosulfan ether 0.846 0.023 84.6 2.7 0.0794 0.0055 79.4 6.9 –1076 61672 Tefluthrin met_2912] 0.500 0.028 50.0 5.5 0.0641 0.0048 64.1 7.5 –1093 61627 3,5-Dichloroaniline 0.881 0.03088.1 3.4 0.0919 0.0067 91.9 7.3 –1099 61614 2,5-Dichloroaniline 0.725 0.03172.5 4.3 0.0810 0.0060 81.0 7.4 –1124 61660 O-Ethyl-O-meth_ioate 0.807 0.024 80.7 2.9 0.0889 0.0065 88.9 7.3 –1126 61645 Fenamiphos sulfone 0.813 0.008 81.3 1.0 0.0886 0.0048 88.6 5.4 –Final Method Validation 43Table 9.Bias and variability data from eight ground-water samples fortified with parent pesticides and degradates at high (1.0 microgram per liter)and low (0.1 microgram per liter) concentrations—ContinuedHigh LowRank P-Code Short nameMedianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Medianconc.(μg/L)F-pseu(μg/L)Medianrecovery(percent)RelF-pseu(percent)Remarkcode1231 61669 Tebupirimphos,_logue 0.840 0.018 84.0 2.1 0.0739 0.0061 73.9 8.2 –1002 61620 2-Ethyl-6-meth_iline 0.772 0.008 77.2 1.0 0.1034 0.0082 103.4 8.0 E1012 61636 Chlorpyrifos, _nalog 0.662 0.072 66.2 10.9 0.0440 0.0088 44.0 19.9 E1013 61617 2-Amino-N-isop_amide 0.548 0.010 54.8 1.8 0.0588 0.0031 58.8 5.2 E1014 61664 Paraoxon-methyl 0.817 0.05881.7 7.1 0.0844 0.0086 84.4 10.2 E1015 61633 4-Chloro-2-met_henol 0.619 0.017 61.9 2.7 0.0681 0.0049 68.1 7.3 E1024 61630 3-Trifluoromet_iline 0.466 0.023 46.6 4.9 0.0518 0.0033 51.8 6.3 E1032 49295 1-Naphthol 0.341 0.083 34.1 24.4 0.0063 0.0018 6.3 28.9 E1032 61611 1,4-Naphthaquinone1-- -- -- -- 0.0781 0.0065 78.1 8.3 E1034 61666 Phorate oxon 0.842 0.016 84.2 1.9 0.0802 0.0079 80.2 9.8 E1053 61635 Azinphos-methyl-oxon 0.810 0.039 81.0 4.8 0.1258 0.0058 125.8 4.6 E1054 61649 Fonofos, oxyge_nalog 0.694 0.038 69.4 5.5 0.0776 0.0067 77.6 8.6 E1067 61641 Disulfoton sulfoxide 0.960 0.029 96.0 3.0 0.0996 0.0056 99.6 5.6 E1076 61671 Tefluthrin met_9364] 0.394 0.044 39.4 11.2 0.0432 0.0046 43.2 10.7 E1101 61631 4,4'-Dichlorob_enone 0.844 0.038 84.4 4.5 0.0928 0.0073 92.8 7.9 E1105 61634 4-Chlorobenzyl_lfone 0.506 0.006 50.6 1.1 0.0552 0.0023 55.2 4.2 E1125 61668 Phosmet oxon 0.735 0.034 73.5 4.7 0.0999 0.0083 99.9 8.3 E1126 61646 Fenamiphos sulfoxide1-- -- -- -- 0.0174 0.0010 17.4 5.9 E1134 61644 Ethion monoxon 0.811 0.034 81.1 4.2 0.1002 0.0043 100.2 4.3 E1153 38775 Dichlorvos 0.451 0.040 45.1 8.8 0.0312 0.0083 31.2 26.5 E1227 61647 Fenthion sulfoxide 0.750 0.022 75.0 3.0 0.0850 0.0061 85.0 7.2 ESurrogates99223 Diazinon-d10, _ogate 1.238 0.028 123.8 2.3 0.0750 0.0030 75.0 4.0 –99224alpha-HCH-d6, _ogate 1.036 0.280 103.6 27.0 0.0941 0.0058 94.1 6.1 –1Terbuthylazine, 1,4-naphthaquinone, and fenamiphos sulfoxidenot included in fortification mixture.

### Method Detection Limits

Short-term met hod detection limits

( M DL s) f o r

pe stic ide s a nd pe stic ide

de g r a d a t e s we r e e s tima te d by de te r mining the

anal y t es i n ei g h t reag ent

- wat e r sam p l e s

fortified at concentra tions of 0.015 μg /L for

m o st anal y t es. The MDL s usual l y are

calculated as about thr ee standard deviations

of the mean concentration (U.S.

Environmental Protection Ag ency , 1997). F o r

this report, the F

- pseudosig ma rather than the

standard deviation was used t o cal cul a t e t h e

MDL s

.

0.99) α 1 1, (



 

n t F MDL

, (11)

w h ere F = F- pseudosig m a of replicate

analy s es, in m i crog ram s per

liter;

n = num ber of replicate sam p les;

t = Student’s t

- v alue for a one- t ailed

test appropriate for the

99- percent confidence lev e l

(1- α = 0.99) with n

- 1 deg r ees

of freedom ; and

α = lev e l of sig n ificance.



### For ei g h t repl i cat es and a 99-percent

confidence level, the value of t is 2.998. The

phrase, short-term MDL

, is used to

dif f e r e ntia te the s e one

- time a nd one

a n a l y tic a l

- i nstr ume n t e s tima te s f r o m long

t e rm MDL s (L T–MDL s ) det e rm i n ed over a

long e r time a nd tha t use r e sults f r o m dif f e r e nt

analy tical instruments (Childress and others,

1999). Ex ercise caution in interpreting these

MDL s and the preliminary L R L s because

they are based on short-term studies, and for

some of the a n a l y t e s , the f o r tif ic a tion le ve l

wa s g r e a t e r tha n 2 to 5 time s the MDL a s

recommended in the procedure (U.S.

Environmental Protection Ag ency , 1997).

Some analy t es that had low recovery or

instrumental response were fortified at successively hig h er concentrations (0.025,

0.075, and 0.1 μg /L ). Samples were analy z ed

on one instrument. The pr e limina r y

e s tima te d

MDL s rang ed from 0.001 to 0.7 μg /L , with a

median MDL of 0.002 μg /L for all analy t es

(table 10). More than 80 percent of the

analy t es had MDL s less than 0.01 μg /L

.

The L R L s are usual l y cal cul a t e d as at

le a s t twic e the L T –MDL s ( C hildr e ss a nd

others, 1999). B ecause of the limitations of

the short-term MDL not ed above, preliminary

L R L s c a l c u la te d using s hort-term MDL s were,

in some c a s e s , muc h lowe r tha n the lowe st

calibration standard that can be measured.

R ecent l y , t h e L R L cal cul a t i on has been

modified to include the bias introduced by low

anal y t e recovery by cal cul a t i n g t h e L R L as

twice the MDL s divided by the median

recovery (ex p ressed as a fraction) (F oreman

and others, 2001). This new calculation

resulted in preliminary L R L s for this method

that were consistent with analy s is of low

cal i b rat i on st andards for m o st anal y t es (t abl e

10) . Eig h t a n a l y t e s ha d c a lc ula t e d pr e limina r y

L R L s that were too low for reliable detection

( g r e a t e r tha n the ma x imum 1 pe r c e n t f a lse

neg a t i v e error rat e ; C h i l d ress and ot hers,

1999). Therefore, the concentration of the

lowe st c a libr a tion sta ndard that could be

rel i a bl y det ect ed was used i n st ead as an

e s tima te of the pr e limina r y

L R L f o r

the s e

analy t es (shown in bold in table 10). The

preliminary L R L s rang e from 0.003 to 0.267

μg /L for most analy t es (table 10).

Dat a A n aly s is

The data summaries presented in tables

6 throug h 10 use nonpara metric equivalents

of the more commonly used summary

sta tistic s. F o r a

de sc r i ption of the data, the

median has been used rather than the

a r ithme tic me a n or a v e r a g e

. Simila r l y

, f o r

the

dispersion or spread of the data, the

44 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr yT a b l e 10. Method detec tion lim its and pr elim inar y labor ator y r epor ting levels f o r pes tic i des and pes tic i de

degr adates c a lc ulated f r om deter m i nation of the analy t es in eight r eagent- w ater s a m p les f o r t if ied at

c onc entr a tions f r om 0.015 to 0.1 m i c r ogr am per liter

[A n a l y t e s are s e parat e d i n t o paren t pes t i c i d es an d deg r adat es an d s o rt ed by rem a rk code an d t h en by ran k

. A n al y s es perf orm e d

o n

o n e in stru m e n t . Ran k

, n a tio n a l ap p licatio n an d u s e ran k o f p e sticid e; P

- Co d e , Natio n a l W a ter In f o rm atio n Sy stem

p a ram e ter co d e ; μg /L , m i cro g ram p e r liter; Med i an co n c ., m e d i an co n cen tratio n ; F- p s eu , F- p s eu d o s ig m a ; Rel F- p s eu , relativ e

F- p s eu d o s ig m a ; MDL

, m e th o d d e tectio n lim it; L R L

, lab o r ato r y rep o r tin g lev e l; bo ld n u m bers are es tim ated L R L s bas e d on

lo w e st calib ratio n stan d a rd o b s erv e d ; – , n o t ap p licab le; E, estim ated q u alif ier rem a rk ]

Ra nk P

- Code S hor t na me Fortificat io n

lev e l

(μg/L) Me d i a n

c onc

. (μg/L) F-ps e u (μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) MD L

(μg/L) Preliminary

LRL

(μg/L) Remark

c ode

Pa rent p e sticid es

6 3 0 4 0 3 6 Prom et ry n 0

. 0 1 5 0

. 0 1 1 2 0.00067 7 4

. 7 6

. 0 0

. 0 0 2 0 0.0054

–

6 9 6 1 6 0 3 Prof en of os 0

. 0 1 5 0

. 0 0 6 7 0.00044 4 4

. 7 6

. 6 0

. 0 0 1 3 0.0059

–

7 1 3 4 3 6 2 al pha

- E n dos u l f a n 0

. 0 1 5 0

. 0 0 7 8 0.00041 5 2

. 3 5

. 2 0

. 0 0 1 2 0.0047

–

7 5 6 1 5 9 6 Met a l a x y l 0

. 0 1 5 0

. 0 1 2 3 0.00069 8 1

. 7 5

. 6 0

. 0 0 2 1 0.0051

–

1 0 6 6 1 6 0 0 O x y f l u orf e n 0

. 0 1 5 0

. 0 0 6 5 0.00053 4 3

. 6 8

. 2 0

. 0 0 1 6 0.0073

–

1 0 8 7 9 8 4 6 cis

- P ropi con azol e 0

. 0 1 5 0

. 0 0 5 6 0.00021 3 7

. 4 3

. 8 0

. 0 0 0 6 0.008

–

1 1 0 7 9 8 4 7 t r ans

- P ropi con azol e 0

. 0 1 5 0

. 0 0 3 0 0.00044 1 9

. 9 1 4

. 8 0

. 0 0 1 3 0.0133

–

1 2 1 6 1 5 9 9 My cl obu t a n i l 0

. 0 1 5 0

. 0 0 5 6 0.00037 3 7

. 4 6

. 6 0

. 0 0 1 1 0.008

–

1 2 6 6 1 5 9 1 F e n a m i ph os 0

. 1 0

. 1 0 1 0 0.00489 1 0 1

. 0 4

. 8 0

. 0 1 5 4 0.0290

–

1 2 7 0 4 0 2 5 H e x azi n o n e 0

. 0 2 5 0

. 0 0 7 9 0.00068 3 1

. 6 8

. 6 0

. 0 0 2 0 0.0129

–

1 2 8 0 4 0 3 1 C y cl oat e 0

. 0 1 5 0

. 0 1 3 3 0.00070 8 8

. 7 5

. 3 0

. 0 0 2 1 0.0047

–

1 3 2 6 1 5 9 8 Met h i d at h i on 0

. 0 1 5 0. 0 0 6 8 0

. 0 0 0 4 4 4 5

. 1 6

. 5 0

. 0 0 1 3 0.0058

–

1 3 4 8 2 3 4 6 Et h i on 0

. 0 1 5 0

. 0 0 5 9 0.00026 3 9

. 4 4

. 4 0

. 0 0 0 8 0.0040

–

2 1 1 7 9 8 4 4 (E)- D i m e t h om orph 0

. 0 7 5 0

. 0 1 2 6 0

. 0 0 0 5 7 1 6

. 8 4

. 6 0

. 0 0 1 7 0.0203

–

2 1 2 7 9 8 4 5 (Z )- D i m e t h om orph 0

. 0 7 5 0

. 0 1 0 4 0.00106 1 3

. 9 1 0

. 2 0

. 0 0 3 2 0.0457

–

2 2 0 0 4 0 2 2 T e rbu t h y l azi n e 0

. 0 1 5 0

. 0 1 3 2 0.00150 8 8

. 0 1 1

. 4 0

. 0 0 4 5 0.0102

–

2 2 5 6 1 5 9 2 F l u m et ral i n 0

. 0 1 5 0

. 0 0 5 3 0.00018 3 5

. 1 3

. 4 0

. 0 0 0 5 0.004

–

2 2 7 3 8 8 0 1 F e n t h i on 0

. 0 1 5 0

. 0 0 6 4 0.00110 4 2

. 8 1 7

. 1 0

. 0 0 3 3 0.0154

–

2 2 8 6 1 5 9 4 Is of en

ph os 0

. 0 1 5 0

. 0 1 0 0 0.00038 6 6

. 9 3

. 8 0

. 0 0 1 1 0.0034

–

2 2 9 6 1 6 0 4 Propet a m p h o s 0

. 0 1 5 0

. 0 1 0 1 0.00043 6 7

. 3 4

. 3 0

. 0 0 1 3 0.0038

–

2 3 1 6 1 6 0 2 T e bu pi ri m p h o s 0

. 0 1 5 0

. 0 1 1 0 0.00067 7 3

. 3 6

. 1 0

. 0 0 2 0 0.0055

–

2 8 8 2 6 6 2 D i m e t h oat e 0

. 0 1 5 0

. 0 0 5 2 0.00035 3 4

. 6 6

. 8 0

. 0 0 1 1 0.0061 E

3 0 6 1 6 1 0 T r i b u p h o s 0

. 0 1 5 0

. 0 0 5 4 0.00026 3 5

. 7 4

. 9 0

. 0 0 0 8 0.0044 E

7 1 3 4 3 5 7 bet a

- E n dos u l f a n 0

. 0 2 5 0

. 0 1 4 5 0.00137 5 8

. 0 9

. 5 0

. 0 0 4 1 0.0142 E

7 6 6 1 6 0 6 T e f l u t h r i n 0

. 0 1 5 0

. 0 0 4 8 0.00041 3 1

. 9 8

. 6 0

. 0 0 1 2 0.0077 E

8 3 3 8 4 5 4 D i crot oph os 0

. 1 0

. 0 3 7 7 0.00530 3 7

. 7 1 4

. 1 0

. 0 1 6 7 0.0843 E

9 3 6 1 5 9 3 Iprodi on e 0

. 1 0

. 4 1 2 0 0.23721 4 1 2

. 0 5 7

. 6 0

. 7 4 5 6 1.4223 E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 0

. 0 2 5 0

. 0 0 4 9 0.00029 1 9

. 6 5

. 9 0

. 0 0 0 9 0.0089 E

1 1 4 6 1 5 8 6 C y perm et h r i n 0

. 0 2 5 0

. 0 0 6 4 0.00037 2 5

. 8 5

. 8 0

. 0 0 1 1 0.0086 E

1 1 5 3 8 7 1 6 S u l p rof o s 0

. 0 1 5 0

. 0 0 3 9 0.00067 2 6

. 0 1 7

. 3 0

. 0 0 2 0 0.0155 E

1 2 5 6 1 6 0 1 Ph os m e t 0

. 0 2 5 0

. 0 0 5 5 0.00029 2 2

. 1 5

. 3 0

. 0 0 0 9 0.0079 E

1 2 9 6 1 5 8 5 C y f l u t h r i n 0

. 0 2 5 0

. 0 1 0 4 0.00019 4 1

. 6 1

. 8 0

. 0 0 0 6 0.008 E

1 3 1 6 1 5 8 0 Bi f e n t h r i n 0

. 0 1 5 0

. 0 0 3 8 0.00022 2 5

. 1 6

. 0 0

. 0 0 0 7 0.0053 E

2 3 0 6 1 6 0 5 S u l f ot e p p 0

. 0 1 5 0

. 0 1 0 6 0.00030 7 0

. 7 2

. 8 0

. 0 0 0 9 0.0025 E

2 3 2 6 1 6 0 7 T e m e ph os 1 0

. 1 0

. 0 3 3 9 0.01509 3 3

. 9 4 4

. 5 0

. 0 3 6 1 0.2669 E

Final Method Validation 45T a b l e 10. Method detec tion lim its and pr elim inar y labor ator y r epor ting levels f o r pes tic i des and pes tic i de

degr adates c a lc ulated f r om deter m i nation of the analy t es in eight r eagent- w ater s a m p les f o r t if ied at

c onc entr a tions f r om 0.015 to 0.1 m i c r ogr am per liter —Continued

Ra nk P

- Code S hor t na me Fortificat io n

lev e l

(μg/L) Me d i a n

c onc

. (μg/L) F-ps e u

(μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) MD L

(μg/L) Preliminary

LRL

(μg/L) Remark

c ode

D e gr adat es

1 0 0 2 6 1 6 1 5 2- [2- E t h y l

- 6

- m _pan o l 0

. 1 0

. 0 8 7 0

. 0 1 8 3 1 8 7

. 4 2 0

. 9 0

. 0 5 7 5 0.1256

–

1 0 0 7 6 1 6 1 8 2- C h loro- 2 ,6- d

_ i l i d e 0

. 0 1 5 0. 0 1 3 0

. 0 0 0 7 0 8 3

. 3 5

. 6 0

. 0 0 2 1 0.0050

–

1 0 0 8 6 1 6 6 5 4- (H y d rox y m e t h _h al i n ) 1 0

. 1 0

. 0 8 1 0.01920 8 0

. 6 2 3

. 6 0

. 0 4 5 5 0.1428

–

1 0 1 6 6 1 6 7 4 T e rbu f os

- O

- a n a _l f o n e 0

. 0 7 5 0

. 0 3 9 0.00587 5 2

. 1 1 5

. 0 0

. 0 1 7 6 0.0676

–

1 0 3 3 6 1 6 2 5 3,4- Dich loroan ilin e 0

. 0 1 5 0

. 0 1 0 0

. 0 0 0 4 9 6 4

. 6 5

. 0 0

. 0 0 1 5 0.0045

–

1 0 4 3 6 1 6 2 9 3- Ph en ox y b en zy _coh ol 0. 0 7 5 0

. 0 4 2 0.00436 5 6

. 1 1 0

. 3 0

. 0 1 3 1 0.0466

–

1 0 4 4 7 9 8 4 2 c

- M et h y l

- 3- (2,_y l at e 0

. 0 1 5 0

. 0 0 4 0.00165 2 5

. 2 1 0

. 5 0

. 0 0 4 9 0.0393

–

1 0 4 4 7 9 8 4 3 t

- M et h y l

- 3- (2,_y l at e 0

. 0 1 5 0

. 0 0 7 0.00250 4 4

. 7 1 9

. 9 0

. 0 0 7 5 0.0335

–

1 0 4 9 6 1 6 6 3 Paraox on

- e t h y l 0. 0 2 5 0

. 0 1 6 0.00063 6 2

. 6 5

. 7 0

. 0 0 1 9 0.008

–

1 0 6 0 6 1 6 5 2 Mal a ox on 0

. 0 2 5 0

. 0 1 3 0.00042 5 0

. 4 6

. 6 0

. 0 0 1 3 0.008

–

1 0 6 2 6 1 6 3 7 2- (4- t ert

- bu t y _x an ol 0

. 0 1 5 0

. 0 1 1 0.00133 7 4

. 0 1 5

. 3 0

. 0 0 4 0 0.0108

–

1 0 6 7 6 1 6 4 0 D i s u l f ot on s u l f on e 0

. 0 1 5 0

. 0 0 6 0.00113 4 2

. 5 7

. 3 0

. 0 0 3 4 0.0159

–

1 0 7 1 6 1 6 4 2 En dos u l f a n et h e r 0

. 0 1 5 0

. 0 1 5 0.00068 1 0 3

. 0 7

. 5 0

. 0 0 2 0 0.0041

–

1 0 7 1 6 1 5 9 0 En dos u l f a n s u l f at e 0

. 0 1 5 0

. 0 0 9 0.00056 5 7

. 8 4

. 8 0

. 0 0 1 7 0.0058

–

1 0 7 6 6 1 6 7 1 T e f l u t h r i n m e t

_ 9 3 6 4 ] 0

. 0 1 5 0

. 0 0 5 0.00083 3 2

. 0 8

. 2 0

. 0 0 2 5 0.0156

–

1 0 9 3 6 1 6 2 7 3,5- Dich loroan ilin e 0

. 0 1 5 0

. 0 1 2 0

. 0 0 0 6 1 7 8

. 0 5

. 9 0

. 0 0 1 8 0.0047

–

1 0 9 9 6 1 6 1 4 2,5- Dich loroan ilin e 0

. 0 1 5 0

. 0 1 0 0

. 0 0 2 9 3 6 7

. 3 1 0

. 9 0

. 0 0 8 8 0.0261

–

1 1 2 4 6 1 6 6 0 O

- Et h y l

- O

- m e t h _i oat e 0. 0 1 5 0

. 0 1 0 0.00094 6 8

. 3 2 4

. 9 0

. 0 0 2 8 0.0083

–

1 1 2 6 6 1 6 4 5 F e n a m i ph os s u l f on e 0

. 0 7 5 0

. 0 2 7 0.00046 3 5

. 7 6

. 9 0

. 0 0 1 4 0.0077

–

1 2 3 1 6 1 6 6 9 T e bu pi ri m p h o s

, _l og u e 0

. 0 1 5 0

. 0 1 0 0.00069 6 5

. 8 7

. 0 0

. 0 0 2 1 0.0063

–

1 0 0 2 6 1 6 2 0 2- Eth y l- 6- m e th _ilin e 0

. 0 1 5 0

. 0 1 1 0

. 0 0 0 5 4 7 2

. 3 5

. 0 0

. 0 0 1 6 0.0045 E

1 0 1 2 6 1 6 3 6 C h l o rpy r i f

os

, _n al og 0

. 0 7 5 0

. 0 2 7 0.00332 3 5

. 4 1 2

. 5 0

. 0 0 9 9 0.0562 E

1 0 1 3 6 1 6 1 7 2- A m i n o- N

- i s op_am i d e 0

. 0 1 5 0

. 0 0 7 0

. 0 0 0 3 8 4 6

. 3 5

. 4 0

. 0 0 1 1 0.0049 E

1 0 1 4 6 1 6 6 4 Paraox on

- m et h y l 0

. 0 7 5 0. 0 4 8 0

. 0 0 3 2 1 6 4

. 3 6

. 7 0

. 0 0 9 6 0.0299 E

1 0 1 5 6 1 6 3 3 4- C h l o ro- 2

- m et _h en ol 0

. 0 1 5 0

. 0 0 7 0.00044 4 6

. 7 6

. 3 0

. 0 0 1 3 0.0056 E

1 0 2 4 6 1 6 3 0 3- T r if lu orom et_ilin e 0

. 0 1 5 0

. 0 0 5 0

. 0 0 0 5 5 3 0

. 5 1 2

. 0 0

. 0 0 1 6 0.0108 E

1 0 3 2 4 9 2 9 5 1- N a ph t h ol 0

. 0 2 5 0

. 0 2 1 0.01212 8 2

. 4 5 8

. 8 0

. 0 3 6 3 0.0882 E

1 0 3 2 6 1 6 1 1 1,4- N a ph t h aqu i n o n e 0

. 0 2 5 0

. 0 0 8 0.00277 3 2

. 6 2 3

. 3 0

. 0 0 8 3 0.0509 E

1 0 3 4 6 1 6 6 6 Ph orat e ox on 0

. 0 7 5 0

. 0 1 2 0.00258 1 5

. 9 1 0

. 3 0

. 0 0 7 7 0.0973 E

1 0 5 3 6 1 6 3 5 A z i n ph os

- m et h y l

- ox on 0

. 0 1 5 0

. 0 2 5 0.00027 3 3

. 5 3

. 3 0

. 0 0 0 8 0.016 E

1 0 5 4 6 1 6 4 9 F o n o f o s

, ox y g e_n a l o g 0

. 0 1 5 0

. 0 0 8 0.00020 5 5

. 9 3

. 2 0

. 0 0 0 6 0.0021 E

1 0 6 7 6 1 6 4 1 D i s u l f ot on s u l f ox i d e 0

. 0 7 5 0

. 0 8 1 0.00040 1 0 7

. 5 8

. 3 0

. 0 0 1 2 0.0024 E

1 0 7 6 6 1 6 7 2 T e f l u t h r i n m e t

_ 2 9 1 2 ] 0

. 0 1 5 0

. 0 0 9 0.00104 6 0

. 3 8

. 1 0

. 0 0 3 1 0.0103 E

1 1 0 1 6 1 6 3 1 4,4'

- D i c h l orob_en o n e 0

. 0 1 5 0

. 0 1 3 0

. 0 0 0 4 8 8 5

. 3 6

. 1 0

. 0 0 1 4 0.0034 E

1 1 0 5 6 1 6 3 4 4- C h l o roben z y l _l f o n e 0. 0 1 5 0

. 0 0 8 0.00265 5 2

. 2 8

. 5 0

. 0 0 8 3 0.0304 E

1 1 2 5 6 1 6 6 8 Ph os m e t ox on 0

. 1 0

. 0 3 1 0.00287 3 1

. 1 8

. 6 0

. 0 0 8 6 0.0553 E

46 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr yT a b l e 10. Method detec tion lim its and pr elim inar y labor ator y r epor ting levels f o r pes tic i des and pes tic i de

degr adates c a lc ulated f r om deter m i nation of the analy t es in eight r eagent- w ater s a m p les f o r t if ied at

c onc entr a tions f r om 0.015 to 0.1 m i c r ogr am per liter —Continued

Ra nk P

- Code S hor t na me Fortificat io n

lev e l

(μg/L) Me d i a n

c onc

. (μg/L) F-ps e u

(μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) MD L

(μg/L) Preliminary

LRL

(μg/L) Remark

c ode

1 1 2 6 6 1 6 4 6 F e n a m i ph os s u l f ox i d e 0

. 0 7 5 0

. 0 3 3 0.00014 4 4

. 5 2

. 2 0

. 0 0 0 4 0.031 E

1 1 3 4 6 1 6 4 4 Et h i on m o n o x o n 0

. 0 1 5 0

. 0 0 6 0.00241 4 3

. 0 2 9

. 6 0

. 0 0 7 2 0.0336 E

1 1 5 3 3 8 7 7 5 D i ch l o rv os 0

. 0 2 5 0

. 0 1 1 0.00089 4 5

. 2 7

. 9 0

. 0 0 2 7 0.0118 E

1 2 2 7 6 1 6 4 7 F e n t h i on s u l f ox i d e 0

. 0 1 5 0

. 0 0 8 0.00068 5 1

. 6 8

. 8 0

. 0 0 2 1 0.0079 E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 0.015 0.081 0.00187 81.0 2.3 0.0056 0.0138

–

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 0.015 0.091 0.00065 91.3 0.7 0.0019 0.0043

–

1 MDL f o r tem e p h o s an d 4

- (h y d ro x y m e th y l )p en d a m e th alin w e re estim ated f r o m reag en t- w a ter set- sp ik e d a ta (tab le 1 7 )

w ith t = 2.39.



### F

- pseudosig ma has been used rather than the

standard deviation. Th e F

- pseudosig ma is

de f i ne d a s the inte r qua r tile r a ng e divide d by

1.349 (Hoag lin, 1983). B ecause the

nonparametric summaries are less likely to be

inf l ue nc e d by a n outly ing r e sult, the y a r e

more robust than their parametric equivalents

in the small data sets produced in the method

validation ex periments.

Re c o v e r y at diffe re nt c onc e n trations:

The median recovery of most compounds was

comparable at 1.0, 0.1, or 0.01 μg /L (tables 6

throug h 10), which indicated no major bias

caused by t h e concent r at i on of t h e anal y t e

over the concentration rang e tested. F o r all

sample matrices, samp les were g r ouped by

concentration and compared by using the

nonparametric Mann-W h itney test to ex amine

the null hy pothesis that the median recoveries

were equal to the median recovery at 0.1 μg /L

in each concentration (Miller and Miller,

1993). F o r other compounds, the median

recoveries were sig n ificantly hig h er ( p <0.05;

Mann-W h itney test) in the 0.1-μg /L sample

set compared to the 1.0-μg /L set. These

di fferences were sm al l (4 to 15 percent) and

mig ht be the result of va r i a tion in instr u me nt perform ance because each sam p l e set (sam e

m a t r i x and concent r at i on) was anal y z ed at

different times. The CCVs for the g r oundwa te r low- c onc e n tr a tion set were also hig h,

perhaps ex pl ai ni ng an i n st rum e nt anal y t i cal

e f

f e c t r a the r tha n sa mple ma tr ix or

concent r at i on effect s for som e of t h e anal y t es

de te r mine d in this se t.

Re c o v e r y in diffe re nt matric e s : The

mean recovery of some compounds was lower

in the r e a g e n t- wa te r sa mple se ts ( t a b le s 6 a nd

7) com p ared t o sam p l e s of surface wat e r

(table 8) or g r ound water (table 9). Ag ain,

these differences were small (4 to 15 percent)

and mig ht be the resu lt of variation in

i n st rum e nt perform ance because each sam p l e

se t wa s a n a l y z e d a t dif f e r e nt time s.

Recommended Holding Time

The r e c o mme nde d holding time of

anal y t es i n pest i c i d e-g r ade wat e r at 4oC and

a f

te r e x tr a c tion on the SPE c o lumn with

storag e on the dry column at room

te mpe r a t ur e wa s e s tima te d by modif y ing a

standard practice (ASTM Procedure

D-4841-88) for estimating holding time for

c onstitue n ts in wa te r sa mple s ( A me r i c a n

Final Method Validation 47

### Society for Testing and Materials, 2000). I n

tha t sta nda r d, the ma x imum holding time is

de f i ne d a s the ma x imum pe r i od tha t a sa mple

can be st ored before t h e anal y t e deg r ades so

t h at t h e sy st em at i c error ex ceeds t h e 99-

percent confi d ence i n t e rval (not t o ex ceed 15

percent ) of t h e m ean concent r at i on

de te r mine d a t time ze r o. Holding time is

e s tima te d by r e plic a t e a n a l y s e s a t disc r e te

time inte r v a l s of a

la r g e volume of sa mple . A

plot of the data then is prepared, and a line is

f it to the da ta . The point whe r e the line

c r osse s the lowe r tole r a ble rang e of variation

is the e s tima te d holding time . An e s tima te of

the a n a l y t e va r i a b ility is ne e d e d to c a l c u la te

t h e num ber of repl i cat es requi red for each

disc r e te time inte r v a l pr ior to de te r mining the

holding time

.

I t should be noted that the holding -time

e s tima te s we r e de te r mine d in r e a g e n t wa te r

. I n e nvir onme n ta l sa mple s, the sa mple ma tr ix

mig ht r e sult in holding time s dif f e r e nt tha n

those de te r mine d in a r e la tive l y c l e a n ma tr ix

like r e a g e n t wa te r

. The s e holding time s a r e

recommended to provide a balance between

t h e pract i cal requi re me nts of sa mple

collection, shipping and processing , and the

limite d inf o r

m a tion pr ovide d by the s e

e s tima te d holding

- time e x pe r ime nts. I n

g e neral, the best approach is to ex tract

samples by SPE and elute from the SPE

column as quickly as possible.

The pract i ce was m odi fi ed for use i n

this r e por t to be tte r ma tc h the da ta pr oduc e d

in the va lida tion e x pe r ime nts a nd ide n tif y

a n a l y t e s tha t ha ve holding time s shor te r tha n

those described in th e complementary method

2001 (Z aug g and others, 1995). I n method

2001, the recommended max imum holding

time s a r e 4 da y s in wa te r pr ior to SPE, a nd 7

day s on the SPE column after SPE (Z aug g

and others, 1995, p. 39). The relative F

pseudosig ma was used instead of the relative

standard deviation to calculate the number of

replicates needed at each discrete time inte r v a l . Simila r l y

, inste a d of the sta nda r d

deviation, the F

- pseudosig ma was used to

calculate the tolerable rang e of variation. The

F

- pseudosig ma g e nerally is similar to the

standard deviation for most compounds, and,

t h erefore, t h e m odi fi cat i on is ex pected to have

little e f f e c t e x c e p t whe n va r i a b ility is hig h

because of outliers. I n that case, the F

pseudosig ma provides a more conservative

estimate than the standa rd deviation. A linear

f it of the da ta r a the r than other g r aphical

e s tima te s wa s use d to e s tima te ma x imum

holding time to simplif y

the a n a l y s is. Visua l

e x a mina tion of the da ta was used to make

sure the linear fit di d not underestimate the

holding time s f o r

wa te r a nd on the SPE

column g i ven in Z a ug g and others (1995),

althoug h, in some cases, other ty pes of

g r aphical fit mig ht pr ovide better numerical

e s tima te s of holding time

.

Calculation of rep licates required for

hol di ng-t i m e experi m ent s : The r e la tive

F

- pseudosig ma of sa mples fortified in

pesticide-g r ade water at 0.1 μg /L (tables 6

a nd 7) wa s use d to e s tima te the numbe r of

sam p l e s needed t o eval uat e a si g n i f i cant

c h a n g e in c onc e n tr a tion ove r time . The

number of replicates re quired for the holding

time ex periments was cal culated according to

the following equation:

n = 2 

### 

 

D Fpseu Rel t  

, (12)

w h ere n = num ber of replicate sam p les;

t = Student' s t

- v alue for a two- tailed

test appropriate for the

99- percent confidence lev e l;

Rel Fpseu = Relativ e F- pseudosig m a

, in percent (tables 6 and 7); and

D = 15 percent, m a xim u m v a riation

from m ean to be tolerated



### .

48 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y

### The value of t is 3.499 for eig h t

repl i cat es and a 99-percent confi d ence l e vel

. F o r most compounds, the calculated number

of repl i cat es n was less than four (tables 11

and 12), so this value was selected as a

practical number of rep l i cat es t o use for t h e

holding

- time study . F o r some of the mor e

vari abl e anal y t es, t h e use of four repl i cat es i s

insuf f i c i e n t to c h a r a c t e r ize the e s tima te d

holding time

.

SPE holding-time experiment: R eag ent

wa te r sa mple s we r e f o r tif ie d with pa r e nt

pesticides or deg r adates at 0.1 μg /L , ex tracted

by SPE, and the column was dried on day

z e ro. The S P E col u m n s t h en were st ored at

room temperature. F our replicate samples

were el ut ed from t h e S P E col u m n s at di scret e

(0, 1, 3, 7, 14, and 28 day s ) intervals over 28

day s . Parent pesticides and deg r adates were

prepared and deter mine d in se pa r a te

ex periments to avoid bias from formation of

de g r a d a t e s dur ing the holding

- time

ex periment.

Pesticide-grade water holding-time

experi m ent : Re a g e n t- wa te r sa mple s we r e

fortified with parent pe st i c i d es or deg r adat es

at 0.1 μg /L and stored at 4oC. F our replicate

sam p l e s were ex t r act ed at discrete (0, 1, 3, 7,

14, and 28 day s ) intervals over 28 day s

. Parent pesticides a nd deg r adates were

prepared and deter mine d in se pa r a te

ex periments to avoid bias from formation of

de g r a d a t e s dur ing the holding

- time

ex periment.

Holding-time data analysis: All

sa mple s f r o m e ithe r the SPE or wa te r holding

time e x pe r ime nts we r e a n a l y z e d in one ba tc h

at the end of the ex periment. The tolerable

variation d tha t wa s c a l c u la te d f r o m the

following formula is listed in tables 13

and 14: d = ±

n Fpseu t 

, (13)

w h ere d = rang e of tolerable v a riation

from initial recov e ry , in

percent;

t = Student' s t

- v alue, for a twotailed test appropriate for the

99- percent confidence lev e l;

Fpseu = F- pseudosig m a (tables 6

and 7) conv erted to

percent; and

n = 4, num ber of replicates.



### The value of t is 3.499 for eig h t

repl i cat es and a 99-percent confi d ence l e vel

. The e s tima te d d value, in percent recovery

,

t h en was subt ract ed from t h e day

- z e ro val u e

to g i ve the lowe r tole r a ble rang e of variation

from the day

- z e ro recovery . Straig ht lines

we r e f it to the da ta , a nd the da y

- ze r o inte r c e p t

was cal cul a t e d from t h e reg r essi on l i n e. The

equation for the reg r ession line is

, (14) 

### b t m R 

w h ere R = recov e ry , in percent;

m = slope of linear reg r ession;

t = tim e, in day s ; and

b = tim e z e ro intercept, in percent

recov e ry

.



### The inte r c e p t of the line a r f

it of the

c onc e n tr a tion in r e la tion to the time line with

the lowe r tole r a ble r a ng e of c onc e n tr a tion

g i ve s the e s tima te d holding time . The slope

a nd inte r c e p t f o r

the line a r f

it of the da ta a r e

pr ovide d to a llow e s tima te s of holding time s

by using othe r e s tima te s of the tole r a ble r a ng e

of variation.

Holding time on dry SPE column: Ten

pa r e nt pe stic ide s ha d holding time s on the dr y SPE column that were 30 day s or less (table

13). Two org a nothiophos phate pesticides,

sulf ote pp a nd sulpr o f o s, ha d holding time s

Final Method Validation 49T a b l e 11. Num ber of r eplic ates r equir ed to deter m i ne es tim a ted holding tim e of par ent pes tic i des in w a ter

and on s o lid- phas e- ex tr ac tion c o lum n s

[Nu m ber of replicates n eeded at each tim e s t ep to es tim ate th e m ean con cen tration w ith in 15 percen t ( n ),

(eq u atio n 1 2 ) ; P

- Co d e , Natio n a l W a ter In f o rm atio n Sy stem p a ram e ter co d e ; –

, n o t ap p licab le; E, estim ated q u alif ier

rem a rk ]

Ra nk P

- Code S hor t na me Number

o f

rep licat es ( n ) Remark

c ode

Pa rent p e sticid es

6 3 0 4 0 3 6 Prom et ry n 1

–

6 9 6 1 6 0 3 Prof en of os 2

–

7 1 3 4 3 6 2 al pha

- E n dos u l f a n 1

–

7 5 6 1 5 9 6 Met a l a x y l 1

–

1 0 6 6 1 6 0 0 O x y f l u orf e n 4

–

1 0 8 7 9 8 4 6 cis

- P ropi con azol e 1

–

1 1 0 7 9 8 4 7 t r ans

- P ropi con azol e 2

–

1 2 1 6 1 5 9 9 My cl obu t a n i l 2

–

1 2 6 6 1 5 9 1 F e n a m i ph os 1

–

1 2 7 0 4 0 2 5 H e x azi n o n e 1

–

1 2 8 0 4 0 3 1 C y cl oat e 1

–

1 3 2 6 1 5 9 8 Met h i d at h i on 1

–

1 3 4 8 2 3 4 6 Et h i on 1

–

2 1 1 7 9 8 4 4 (E)- D i m e t h om orph 2

–

2 1 2 7 9 8 4 5 (Z )- D i m e t h om orph 1

–

2 2 0 0 4 0 2 2 T e rbu t h y l azi n e 1 2

–

2 2 5 6 1 5 9 2 F l u m et ral i n 3

–

2 2 7 3 8 8 0 1 F e n t h i on 2

–

2 2 8 6 1 5 9 4 Is of en

ph os 2

–

2 2 9 6 1 6 0 4 Propet a m p h o s 1

–

2 3 1 6 1 6 0 2 T e bu pi ri m p h o s 2

–

2 8 8 2 6 6 2 D i m e t h oat e 3 0 E

3 0 6 1 6 1 0 T r i b u p h o s 8 E

7 1 3 4 3 5 7 bet a -E nd o s ul fa n 1 E

7 6 6 1 6 0 6 T e f l u t h r i n 1 0 E

8 3 3 8 4 5 4 D i crot oph os 3 1 E

9 3 6 1 5 9 3 Iprodi on e 2 E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 9 E

1 1 4 6 1 5 8 6 C y perm et h r i n 2 6 E

1 1 5 3 8 7 1 6 S u l p rof o s 4 E

1 2 5 6 1 6 0 1 Ph os m e t 3 E

1 2 9 6 1 5 8 5 C y f l u t h r i n 2 2 E

1 3 1 6 1 5 8 0 Bi f e n t h r i n 1 7 E

2 3 0 6 1 6 0 5 S u l f ot e p p 1 E

2 3 2 6 1 6 0 7 T e m e ph os 1 7 E

S u r r ogat es

9 9 2 2 3 D i a z i no n- d 10 , _og ate 1

–

9 9 2 2 4 al pha -H CH

- d 6 , _og ate 1

–

1 T e rbu t h y lazin e an d tem e ph os are n o t in clu d ed in h o ldin g

- tim e ex perim e n t s

.

50 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr yFinal Method Validation 51 Table 12. Number of replicates required to determine estimated holding time of degradates in water and

on solid-phase-extraction columns

[Number of replicates needed at each time step to estimate the mean concentration within 15 percent ( n ), (equation 12);

P-Code, National Water Information System parameter code; –, not applicable; E, estimated qualifier remark]

Rank P-Code Short name Number

of replicates ( n ) Remark

code

Degradates

1002 61615 2-[2-Ethyl-6-m_panol 3

–

1007 61618 2-Chloro-2 ,6-d_ilide 1

–

1008 61665 4-(Hydroxymeth_halin 5

–

1014 61664 Paraoxon-methyl 1

–

1033 61625 3,4-Dichloroaniline 6

–

1043 61629 3-Phenoxybenzy_cohol 1

–

1044 79842 c -Methyl-3-(2,_ylate 1

–

1044 79843 t -Methyl-3-(2,_ylate 2

–

1049 61663 Paraoxon-ethyl 1 1

–

1060 61652 Malaoxon 2

–

1062 61637 2-(4-tert-buty_xanol 3

–

1067 61640 Disulfoton sulfone 1

–

1071 61642 Endosulfan ether 1

–

1071 61590 Endosulfan sulfate 1 1

–

1076 61672 Tefluthrin met_2912] 1

–

1076 61671 Tefluthrin met_9364] 4

–

1093 61627 3,5-Dichloroaniline 3

–

1099 61614 2,5-Dichloroaniline 2

–

1124 61660 O-Ethyl-O-meth_ioate 2

–

1126 61645 Fenamiphos sulfone 4

–

1231 61669 Tebupirimphos,_logue 1

–

1002 61620 2-Ethyl-6-meth_iline 1 E

1012 61636 Chlorpyrifos, _nalog 45 E

1013 61617 2-Amino-N-isop_amide 13 E

1015 61633 4-Chloro-2-met_henol 11 E

1016 61674 Terbufos-O-ana_lfone 5 E

1024 61630 3-Trifluoromet_iline 4 E

1032 49295 1-Naphthol 89 E

1032 61611 1,4-Naphthaquinone 53 E

1034 61666 Phorate oxon 4 E

1053 61635 Azinphos-methyl-oxon 22 E

1054 61649 Fonofos, oxyge_nalog 1 E

1067 61641 Disulfoton sulfoxide 2 E

1101 61631 4,4'-Dichlorob_enone 1 E

1105 61634 4-Chlorobenzyl_lfone 7 E

1125 61668 Phosmet oxon 66 E

1126 61646 Fenamiphos sulfoxide 8 E

1134 61644 Ethion monoxon 2 E

1153 38775 Dichlorvos 1 2 E

1227 61647 Fenthion sulfoxide 2 E

Surrogates

99223 Diazinon- d 10 , _ogate 2

–

99224 alpha -HCH- d 6 , _ogate 2

–

1 Dichlorvos, endosulfan sulfate, and paraoxon-ethyl were analyzed in parent fortification mixture.T a b l e 13. Statis tic a l data us ed to deter m i ne es tim a ted holding ti m e of par ent pes tic i des on dr y s o lid- phas e- ex tr ac tion

c o lum n s m a intained at 25 degr ees Cels ius

[Ho l d i n g tim es less th an 7 d a y s sh o w n

in b o l d f ace. Reag en t- w a ter sam p les w e re f o rtif ied at 0

. 1 m i cro g ram p e r liter, iso l ated o n

t h e S P E col u m n

on day 0, an d f o u r repl i cat e s a m p l e s w e re el u t ed f r om t h e S P E col u m n

on day s 0, 1, 3, 7, 14, an d 28. P- C ode,

Natio n a l W a ter In f o rm atio n Sy stem p a ram e ter co d e ; d , to lerab l e ran g e o f v a riatio n in in itial co n cen tratio n (in p e rcen t reco v e ry );

Mean –d , m ean recov e ry on day 0 m i n u s d ; In tercep t, in tercep t o f lin ear f it to h o ld in g

- tim e resu lts; Slo p e , slo p e o f lin ear f it to

h o ld in g

- tim e resu lts; Ho ld in g tim e, estim ated h o ld in g tim e (d ay s) fr o m le a s t-sq ua r e s r e gr e ssio n ( u sing a str a ight-line m o d e l) ; --,

es tim ated h o ldin g tim e g r eater th an 28 day s becau s e com pou n d did n o t decreas e in co n cen tration ov er 28- day tes t period; –, no t

ap p licab le; E, estim ated q u alif ier rem a rk ]

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) In t e rcep t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

Pa rent p e sticid es

6 3 0 4 0 3 6 Prom et ry n 6

. 0 8 4

. 8 7 8

. 7 8 3

. 3 0

. 0 1 4

- - –

6 9 6 1 6 0 3 Prof en of os 6

. 1 7 0

. 9 6 4

. 8 6 9

. 7

- 0

. 9 5 5 7

–

7 1 3 4 3 6 2 al pha

- E n dos u l f a n 4

. 5 9 7

. 8 9 3

. 3 1 0 2

. 0 0

. 0 2 6

- - –

7 5 6 1 5 9 6 Met a l a x y l 5

. 8 8 8

. 3 8 2

. 5 8 8

. 5

- 0

. 0 4 3

- - –

1 0 6 6 1 6 0 0 O x y f l u orf e n 7

. 3 6 3

. 9 5 6

. 5 6 3

. 5

- 0

. 1 7 0

- - –

1 0 8 7 9 8 4 6 cis

- P ropi con azol e 3

. 4 7 0

. 0 6 6

. 6 7 0

. 9 0

. 0 2 5

- - –

1 1 0 7 9 8 4 7 t r ans

- P ropi con azol e 5

. 9 8 2

. 5 7 6

. 6 8 2

. 8 0

. 0 0 7

- - –

1 2 1 6 1 5 9 9 My cl obu t a n i l 5

. 8 7 8

. 5 7 2

. 6 7 9

. 5

- 0

. 0 0 1

- - –

1 2 6 6 1 5 9 1 F e n a m i ph os 4

. 0 5 4

. 6 5 0

. 6 6 6

. 5

- 0

. 0 8 5

- - –

1 2 7 0 4 0 2 5 H e x azi n o n e 2

. 4 5 6

. 5 5 4

. 1 6 0

. 8

- 0

. 0 8 6 2 8

–

1 2 8 0 4 0 3 1 C y cl oat e 5

. 1 7 7

. 8 7 2

. 6 7 6

. 2 0

. 1 1 4

- - –

1 3 2 6 1 5 9 8 Met h i d at h i on 3

. 1 7 5

. 9 7 2

. 7 7 6

. 5 0

. 0 2 1

- - –

1 3 4 8 2 3 4 6 Et h i on 2

. 7 6 6

. 6 6 4

. 0 6 5

. 8

- 0

. 0 4 8

- - –

2 1 1 7 9 8 4 4 (E)- D i m e t h om orph 7

. 7 6 8

. 5 6 0

. 9 6 8

. 9

- 0

. 0 3 8

- - –

2 1 2 7 9 8 4 5 (Z )- D i m e t h om orph 5

. 5 6 3

. 9 5 8

. 4 6 5

. 2

- 0

. 0 7 5

- - –

2 2 0 0 4 0 2 2 T e rbu t h y l azi n e 1 7

. 7

– – – – – –

2 2 5 6 1 5 9 2 F l u m et ral i n 6

. 3 6 8

. 6 6 2

. 3 6 9

. 9

- 0

. 2 5 4 2 5

–

2 2 7 3 8 8 0 1 F e n t h i on 6

. 2 8 5

. 5 7 8

. 8 8 2

. 3

- 1

. 3 6 3 2 7

–

2 2 8 6 1 5 9 4 Is of en

ph os 4

. 3 8 5

. 0 7 8

. 3 8 2

. 1

- 0

. 0 3 8

- - –

2 2 9 6 1 6 0 4 Propet a m p h o s 5

. 8 8 2

. 6 8 3

. 8 8 1

. 6

- 0

. 0 2 2

- - –

2 3 1 6 1 6 0 2 T e bu pi ri m p h o s 2 1

. 0 8 9

. 6 0

. 0 8 7

. 1

- 0

. 0 1 9

- - –

2 8 8 2 6 6 2 D i m e t h oat e 6

. 7 1 6

. 7 4 6

. 4 1 6

. 7

- 0

. 0 0 4 2

- - E

3 0 6 1 6 1 0 T r i b u p h o s 3

. 9 5 3

. 1 3 8

. 4 5 0

. 8

- 0

. 2 8 7 2 2 4 E

7 1 3 4 3 5 7 bet a

- E n dos u l f a n 5

. 7 1 0 7

. 2 1 0 1

. 4 1 0 9

. 8

- 0

. 1 9 3 3 0 E

7 6 6 1 6 0 6 T e f l u t h r i n 6

. 1 4 2

. 3 4

. 5 4 0

. 3

- 0

. 0 1 8

- - E

8 3 3 8 4 5 4 D i crot oph os 4

. 3 1 0

. 6 8 7

. 2 1 4

. 9 0

. 0 8 6

- - E

9 3 6 1 5 9 3 Iprodi on e 2

. 0 9 1

. 4 2 9

. 2 8 8

. 2 0

. 0 7 2 2

- - E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 1 1

. 6 3 1

. 2 3 6

. 4 3 0

. 2

- 0

. 0 9 0 2 2 2 E

1 1 4 6 1 5 8 6 C y perm et h r i n 7

. 4 4 8

. 0 3 1

. 9 4 9

. 9

- 0

. 0 7 5 2

- - E

1 1 5 3 8 7 1 6 S u l p rof o s 7

. 8 7 1

. 6 6 3

. 8 6 8

. 8

- 1

. 4 1 5 6 E

1 2 5 6 1 6 0 1 Ph os m e t 1 0

. 7 3 9

. 3 3 6

. 5 3 7

. 3

- 0

. 2 8 1 2 2 7 E

1 2 9 6 1 5 8 5 C y f l u t h r i n 4

. 0 4 7

. 1 2 9

. 0 5 0

. 9

- 0

. 0 2 9

- - E

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 52T a b l e 13. Statis tic a l data us ed to deter m i ne es tim a ted holding ti m e of par ent pes tic i des on dr y s o lid- phas e- ex tr ac tion

c o lum n s m a intained at 25 degr ees Cels ius

— Continued

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) In t e rcep t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

1 3 1 6 1 5 8 0 Bi f e n t h r i n 9

. 0 3 2

. 9 7 6

. 5 3 2

. 2 0

. 0 5 3 2

- - E

2 3 0 6 1 6 0 5 S u l f ot e p p 4

. 1 8 3

. 2 7 9

. 1 8 0

. 2

- 1

. 2 1 8 4 E

2 3 2 6 1 6 0 7 T e m e ph os 1 7

. 0

– – – – – E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 3.7 97.9 94.2 94.6

- 0 .316 12

–

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 5.7 91.0 85.3 88.9

- 0 .126

- - –

1 T e r b ut hy l a z i ne a n d t e m e p h o s w e r e no t i n c l ud e d i n ho l d i ng-t i m e e x p e r i m e nt s.

2 H o l d i n g t i m es (day s ) w e re correct ed i n pdf v e rs i o n of t h e report

, F e bru a ry 4, 2002 (m w s ).

T a b l e 14. Statis tic a l data us ed to deter m i ne es tim a ted holding tim e of degr adates on s o lid- phas e- ex tr ac tion c o lum n s

m a intained at 25 degr ees Cels ius

[Ho l d i n g tim es less th an 7 d a y s sh o w n

in b o l d f ace. Reag en t- w a ter sam p les w e re f o rtif ied at 0

. 1 m i cro g ram p e r liter, iso l ated o n

t h e S P E col u m n

on day 0, an d f o u r repl i cat e s a m p l e s w e re el u t ed f r om t h e S P E col u m n

on day s 0, 1, 3, 7, 14, an d 28. P- C ode,

Natio n a l W a ter In f o rm atio n Sy stem p a ram e ter co d e ; d , to lerab l e ran g e o f v a riatio n in in itial co n cen tratio n (in p e rcen t reco v e ry );

Mean –d , m ean recov e ry on day 0 m i n u s d ; In tercep t, in tercep t o f lin ear f it to h o ld in g

- tim e resu lts; Slo p e , slo p e o f lin ear f it to

h o ld in g

- tim e resu lts; Ho ld in g tim e, estim ated h o ld in g tim e (d ay s) fr o m le a s t-sq ua r e s r e gr e ssio n ( u sing a str a ight-line m o d e l) ; –,

n o t applicable; -

- , es tim ated h o ldin g tim e g r eater th an 28 day s becau s e com pou n d did n o t decreas e in con cen tration ov er 28- day

test p e rio d ; E, estim ated q u alif ier rem a rk ]

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) Inte r c e p t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

D e gr adat es

1 0 0 2 6 1 6 1 5 2- [2- E t h y l

- 6

- m _pan o l 9

. 3 9 1

. 8 8 2

. 5 9 0

. 1

- 0

. 8 3 6 1 2

–

1 0 0 7 6 1 6 1 8 2- C h loro- 2 ,6- d

_ i l i d e 3

. 2 9 2

. 9 89. 8 9 4

. 6

- 0

. 1 5 3 2 1

–

1 0 0 8 6 1 6 6 5 4- (H y d rox y m e t h _h al i n 1 3

. 5 9 1

. 0 7 7

. 5 9 2

. 1 0

. 1 0 5

- - –

1 0 1 6 6 1 6 7 4 T e rbu f os

- O

- a n a _l f o n e 1 4

. 7 9 3

. 9 9 1

. 2 8 7

. 4

- 1

. 0 6 0 1 2

–

1 0 4 3 6 1 6 2 9 3- Ph en ox y b en zy _coh ol 4

. 2 7 0

. 0 6 5

. 8 7 4

. 7

- 0

. 3 3 4 1 3

–

1 0 4 4 7 9 8 4 2 c

- M et h y l

- 3- (2,_y l at e 4

. 9 9 5

. 4 9 0

. 5 9 3

. 2

- 0

. 1 0 1

- - –

1 0 4 4 7 9 8 4 3 t

- M et h y l

- 3- (2,_y l at e 7

. 0 9 4

. 4 8 7

. 4 9 4

. 6

- 0

. 1 0 9

- - –

1 0 4 9 6 1 6 6 3 Paraox on

- e t h y l 1 5

. 0 7 0

. 5 6 5

. 5 6 7

. 8

- 0

. 5 9 6 9

–

1 0 6 0 6 1 6 5 2 Mal a ox on 9

. 1 9 2

. 6 8 3

. 5 8 8

. 5

- 0

. 8 5 5 1 1

–

1 0 6 2 6 1 6 3 7 2- (4- t ert

- bu t y _x an ol 9

. 9 8 3

. 6 7 3

. 7 8 8

. 0

- 0

. 1 5 7

- - –

1 0 6 7 6 1 6 4 0 D i s u l f ot on s u l f on e 5

. 8 8 6

. 0 8 0

. 2 8 6

. 3

- 0

. 0 4 9

- - –

1 0 7 1 6 1 6 4 2 En dos u l f a n et h e r 4

. 7 1 0 5

. 8 1 0 1

. 1 1 0 8

. 9

- 0

. 2 3 3 2 1

–

1 0 7 1 6 1 5 9 0 En dos u l f a n s u l f at e 1 5

. 7 1 0 2

. 5 9 6

. 8 1 0 3

. 4

- 0

. 0 3 2

– –

1 0 7 6 6 1 6 7 2 T e f l u t h r i n m e t

_ 2 9 1 2 ] 4

. 2 6 9

. 0 6 4

. 8 6 9

. 2

- 0

. 2 9 1 1 5

–

1 0 9 3 6 1 6 2 7 3,5- Dich loroan ilin e 11. 2 1 0 7

. 5 9 6

. 3 1 0 9

. 6

- 0

. 7 9 4 1 5

–

1 0 9 9 6 1 6 1 4 2,5- Dich loroan ilin e 8. 8 8 9

. 5 8 0

. 7 9 2

. 4

- 0

. 2 6 8

- - –

1 1 2 4 6 1 6 6 0 O

- Et h y l

- O

- m e t h _i oat e 8

. 3 8 7

. 8 7 9

. 5 8 9

. 3

- 0

. 0 4 2

- - –

Final Method Validation 53T a b l e 14. Statis tic a l data us ed to deter m i ne es tim a ted holding tim e of degr adates on s o lid- phas e- ex tr ac tion c o lum n s

m a intained at 25 degr ees Cels ius

— Continued

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) Inte r c e p t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

1 1 2 6 6 1 6 4 5 F e n a m i ph os s u l f on e 9

. 3 6 5

. 2 5 5

. 9 6 7

. 3

- 0

. 1 5 2

- - –

1 2 3 1 6 1 6 6 9 4

. 4 7 8

. 7 8 0

. 5

- 0

. 3 7 5

–

6 1 6 2 0 2- Eth y l- 6- m e th _ilin e 8 7

. 0 8 3

. 6

- 0

. 7 8 3 5 T e bu pi ri m p h o s

, _l og u e 7 4

. 3 1 2

1 0 0 2 3

. 4 9 5

. 5 E

1 0 1 2 6 1 6 3 6 C h l o rpy r i f

os

, _n al og 8

. 8 7 1

. 0 6 2

. 2 6 0

. 7

- 1 7

. 9 6 3 1 E

1 0 1 3 6 1 6 1 7 2- A m i n o- N

- i s op_am i d e 1 5

. 4 9 3

. 4 7 8

. 0 9 5

. 2

- 0

. 1 5 9

- - E

1 0 1 4 6 1 6 6 4 Paraox on

- m et h y l 1 2

. 4 5 7

. 4 8 1

. 6 5 2

. 4

- 0

. 8 7 9 1 2 E

1 0 1 5 6 1 6 3 3 4- C h l o ro- 2

- m et _h en ol 3

. 9 7 8

. 0 7 9

. 9 0

. 0 4 8 5

1 0 2 4 3- T r if lu orom et_ilin e 1 7

. 2 6 0

. 8 6 1

. 4

- - E

1 0 3 2 4 9 2 9 5 5

. 3 2 2 9

. 3 1 4 5

. 7

- 5

. 8 8 6 E

6 1 6 1 1 1,4- N a ph t h aqu i n o n e 1 8

. 2 2 2

. 2 2 0

. 1

- 1

. 1 8 6 E

6 1 6 2 5 3,4- Dich loroan ilin e 1 0

. 3 7 6

. 7 1 0 8

. 3

- 1

. 3 2 1 E

6 1 6 6 6 Ph orat e ox on 8 6

. 9 2 1 1

. 3

- 2

. 1 0 7 4

1 0 5 3 A z i n ph os

- m et h y l

- ox on 2 0

. 0 5 3

. 5 4 8

. 8

- 0

. 4 7 9

- - 5 3

. 6 E

6 1 6 3 0 5 6

. 5

- 0

. 8 5 2

1- N a ph t h ol 5 1

. 2 7

1 0 3 2 4 0

. 4 1 6

1 0 3 3 1 0 5

. 9 5

1 0 3 4 1 8

. 0 7 7

. 2 E

6 1 6 3 5 3 3

. 5 E

1 0 5 4 6 1 6 4 9 F o n o f o s

, ox y g e_n a l o g 3

. 4 8 2

. 7 7 9

. 3 7 7

. 8

- 1

. 4 1 2 3 E

1 0 6 7 6 1 6 4 1 D i s u l f ot on s u l f ox i d e 1 2

. 2 1 5 3

. 5 1 4 1

. 3 0

. 3 4 3

- - E

1 0 7 6 6 1 6 7 1 6

. 0 6 9

. 8 6 9

. 2

- 0

. 5 8 3 E

6 1 6 3 1 4,4'

- D i c h l orob_en o n e 4

. 6 7 5

. 5 8 1

. 0 5 E 1 7 2

. 4

T e f l u t h r i n m e t

_ 9 3 6 4 ] 6 3

. 8 1 1

1 1 0 1 8 0

. 1

- 0

. 9 5 7

1 1 0 5 6 1 6 3 4 4- C h l o roben z y l _l f o n e 1 2

. 8 5 8

. 2 4 5

. 4 6 2

. 9

- 0

. 0 5 5

- - E

1 1 2 5 6 1 6 6 8 Ph os m e t ox on 1 7

. 9 3 1

. 0 1 3

. 1 1 9

. 9

- 0

. 1 9 4

- - E

1 1 2 6 6 1 6 4 6 F e n a m i ph os s u l f ox i d e 5

. 0 1 5

. 3 1 0

. 3 1 9

. 6

- 0

. 0 0 8

- - E

1 1 3 4 6 1 6 4 4 Et h i on m o n o x o n 3

. 8 6 7

. 7 6 3

. 9 6 6

. 9

- 0

. 1 9 8 2 0 E

1 1 5 3 3 8 7 7 5 D i ch l o rv os 1 7

. 1 5 9

. 8 5 2

. 6 3 8

. 9

- 1

. 6 7 2 5 E

1 2 2 7 6 1 6 4 7 F e n t h i on s u l f ox i d e 6

. 2 6 9

. 6 6 3

. 4 7 0

. 5

- 0

. 0 5 7

- - E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 9.0 101.3 92.3 102.9

- 0 .321 28

–

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 5.0 100.9 96.0 100.1 0.002

- - –

1 Dich lorv os , en dos u l f a n

s u lf ate, an d paraox on

- e th y l w e re an aly zed in paren t f

o rtif ication m i x t u r e.



### l e ss t h an 7 day s . Because t h i s i s short e r t h an

the holding time recommended in method

2001 (Z aug g and others, 1995), these

compounds are reported with an estimated

r e ma r k

qua lif ie r

. Another org a nothiophosphate pesticide, prof enofos, had a slig htly

long e r holding time of 7 da y s

.

More pesticide deg r adates (table 14) had

holding time s le ss tha n 30 da y s whe n

compared to the parent pesticides (table 13).

Eig h t de g r a d a t e s ha d e s tima te d holding time s

less than 7 day s . This is shorter than the holding time recommended in method 2001

(Z aug g and others, 1995), so these

compounds are reported with an estimated

remark qualifier. Two org a nophosphate

deg r adates, chlorpy r ifos ox y g en analog and

fonophos ox y g en analog , appeared to be

unsta ble with holding time s of 3 da y s or le ss.

This mig ht e limina t e a n y a dva nta g e s to onsite SPE for these compounds.

Holding time in pe stic ide

- grade wate r: Twelve parent pestic ides had calculated

54 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y

### holding time s in pe stic ide

- g r a d e wa te r of le ss

than 30 day s (table 15). An org a nothiophosphate pesticide (phos met), an isomer of

an org a nochlorine pesticide ( beta

endosulfan), and a py rethroid pesticide

( c y h a l othr in) ha d holding time s of 4 da y s or

le ss, whic h is the r e c o mme nde d holding time

in water for method 2001. As a result, these

a n a l y t e s a r e r e por te d with a n e s tima te d

r e ma r k

qua lif ie r

.

I n addition to cy halothrin, other

py rethroid pesticides, cy fluthrin,

cy permethrin, and tefl uthrin had calculated

holding time s of le ss tha n 30 da y s . This

mig ht be caused by sorption to the walls of

the g l a ss sa mple bottle s ove r the dur a tion of

the ex periments because these compounds

ha ve hig h oc ta nol- w a t e r pa r tition c o e f f i c i e n ts

(log K

ow 

### ) com p ared t o t h e ot her anal y t es

(Mackay and others, 1997). None of the

de g r a d a t e s ha d holding time s in wa te r le ss

than 4 day s (table 16).

Fort i f i ed R eagent

- W at er- S et

Samples

Envir onme n ta l wa te r sa mple s c o lle c t e d

by some NAW QA projects were analy z ed in

1999 as part of a pilot test during

implementation of the new method. Reag entwa te r sa mple s we r e f o r tif ie d with the a n a l y t e s

at 0.1 μ g /L and analy z ed with each set of 10

sa mple s. The me dia n r e c ove r y

a nd va r i a b ility

of 74 of these fortified reag ent-water-set

sam p l e s prepared duri n g March–Decem ber,

1999, are listed in table 17. Deg r adates were

included in all 74 samp les, while parent

pe stic ide s we r e inc l ude d only in the last 49

sa mple s. The s e f o r tif ie d r e a g e n t- wa te r

- s e t

sa mple s a r e c o mpa r a b le to the lowconcentration, reag ent-water samples

analy z ed during method validation (tables 6

and 7). They probably better represent the

perform ance of t h e anal y t es i n pest i c i d e-g r ade

wat e r because t h ey were anal y z ed i n m a ny

different sets and over a long er period c o mpa r e d to the r e a g e n t- wa te r da ta liste d in

tables 6 and 7. F o r most analy t es, median

r e c ove r y

in the f o r tif ie d r e a g e n t- wa te r

- s e t

sa mple s wa s c o mpa r a b le to tha t in the

reag ent-water method valid ation data listed in

tables 6 and 7, althoug h the variability is

some wha t la r g e r

.

N O TE: During the pilot test of the method,

e nvir onme n ta l sa mple s were ex t r act ed by

SPE, g e nerally within 4 day s of collection,

processed, and t h e ex t r act s st ored i n a freez er

until GC/MS a n a l y s is. Re pe a t e d GC/MS

analy s is of a CCV standard stored for a 20-

week period indicated no sig n ificant loss of

any anal y t es.

The averag e m e di an recovery for t h e

f o r tif ie d r e a g e n t- wa te r

- s e t sa mple s f o r

a ll

compounds was 68 percent, with an averag e F

pseudosig ma of 12 percent.

Some analy t es, however, ex hibited

sig n if ic a n tly la r g e r va r i a b ility in the f o r tif ie d

r e a g e n t- wa te r

- s e t sa mple s, pe r h a p s indic a ting

anal y t es t h at are m o re suscept i b l e t o

procedural error than others. A plot of the

median concentration and F

- pseudosig ma for

all analy t es is shown in fig u re 2. A line of

relative F

- pseudosig ma e qual to 25 percent is

plotted to indicate analy t es that have hig h F

pseudosig ma compared to other analy t es.

Compounds that had an F

- pseudosig ma

g r eat er t h an 25 percent i n cl ude t h e fol l o wi ng :

1,4-naphthaquinone; 1-naphthol, 3-

tr if luor ome t hy la niline ; 4- c h lor o

- 2

- methy l phenol; az inphos-methy l-ox on;

chlorpy r ifos ox y g en analog , cy halothrin;

cy permethrin; dichlorvos; ethion monox on;

fenamiphos sulfox ide; fenthion sulfox ide;

iprodione; phosmet; phosmet ox on; and

temephos.

Qualification of Some Compounds

During quantitative method validation,

some compounds ex hibited performance

Final Method Validation 55T a b l e 15. Statis tic a l data us ed to deter m i ne es tim a ted holding tim e of par ent pes tic i des in pes tic i de- gr ade w a ter

m a intained at 4 degr ees Cels ius

[A n a ly tes w ith h o ld in g tim es less th an 4 d a y s sh o w n

in b o l d

. Reag en t- w a ter sam p les w e re f o rtif ied at 0

. 1 m i cro g ram p e r

liter, an d f o u r rep licate sam p les w e re ex tracted an d p r ep ared f o r an aly s is o n d a y s 0

, 1

, 3

, 7

, 1 4

, an d 2 8

. P

- Co d e , Natio n a l

Water In f o rm ation S y s t em param e ter code; d , tolerable ran g e of v a riation f

r om m ean recov e ry , in percen t; Mean –d, m ean

reco v e ry o n d a y 0 m i n u s d ; In tercep t, in tercep t o f lin ear f it to h o ld in g

- tim e resu lts; Slo p e , slo p e o f lin ear f it to h o ld in g

- ti me

res u lts ; -

- , es tim ated h o ldin g tim e g r eater th an 28 day s becau s e com pou n d did n o t decreas e in con cen tration ov er 28- day tes t

peri od;

–, n o t ap p licab le; E, estim ated q u alif ier rem a rk ]

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) Inte r c e p t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

Pa rent p e sticid es

6 3 0 4 0 3 6 Prom et ry n 6

. 0 8 4

. 7 7 8

. 7 8 4

. 9 0

. 1 4 2

- - –

6 9 6 1 6 0 3 Prof en of os 6

. 1 7 2

. 2 6 6

. 0 6 6

. 8

- 0

. 8 3 2 8

–

7 1 3 4 3 6 2 al pha

- E n dos u l f a n 4

. 5 9 2

. 2 8 7

. 7 8 0

. 7

- 0

. 8 5 1 6

–

7 5 6 1 5 9 6 Met a l a x y l 5

. 8 8 7

. 9 8 2

. 1 9 0

. 5 0

. 2 0 4

- - –

1 0 6 6 1 6 0 0 O x y f l u orf e n 7

. 3 6 1

. 8 5 4

. 5 5 8

. 6

- 0

. 1 2 4

- - –

1 0 8 7 9 8 4 6 cis

- P ropi con azol e 3

. 4 6 9

. 7 6 6

. 2 6 8

. 0

- 0

. 0 1 7

- - –

1 1 0 7 9 8 4 7 t r ans

- P ropi con azol e 5

. 9 7 9

. 7 7 3

. 8 7 7

. 2 0

. 0 2 3

- - –

1 2 1 6 1 5 9 9 My cl obu t a n i l 5

. 8 7 6

. 4 7 0

. 6 7 6

. 2 0

. 0 8 6

- - –

1 2 6 6 1 5 9 1 F e n a m i ph os 4

. 0 7 0

. 9 6 6

. 9 7 0

. 2 0

. 1 4 1

- - –

1 2 7 0 4 0 2 5 H e x azi n o n e 2

. 4 6 2

. 4 6 0

. 0 6 0

. 7

- 0

. 2 7 2 9

–

1 2 8 0 4 0 3 1 C y cl oat e 5

. 1 8 1

. 0 7 5

. 8 8 4

. 4

- 0

. 2 2 4 2 4

–

1 3 2 6 1 5 9 8 Met h i d at h i on 3

. 1 7 1

. 1 6 8

. 0 6 9

. 3

- 0

. 0 4 5

- - –

1 3 4 8 2 3 4 6 Et h i on 2

. 7 6 4

. 6 6 1

. 9 6 2

. 4

- 0

. 0 4 2

- - –

2 1 1 7 9 8 4 4 (E)- D i m e t h om orph 7

. 7 7 1

. 4 6 3

. 8 7 3

. 9 0

. 0 0 8

- - –

2 1 2 7 9 8 4 5 (Z )- D i m e t h om orph 5

. 5 6 9

. 0 6 3

. 5 6 8

. 5 0

. 0 4 0

- - –

2 2 0 0 4 0 2 2 T e rbu t h y l azi n e 1 7

. 7

– – – – – –

2 2 5 6 1 5 9 2 F l u m et ral i n 6

. 3 6 6

. 2 5 9

. 9 6 4

. 7

- 0

. 0 4 2

- - –

2 2 7 3 8 8 0 1 F e n t h i on 9

. 0 7 7

. 9 6 8

. 9 7 9

. 9 0

. 0 8 0

- - –

2 2 8 6 1 5 9 4 Is of en

ph os 6

. 2 8 5

. 3 7 9

. 1 8 3

. 7 0

. 0 3 5

- - –

2 2 9 6 1 6 0 4 Propet a m p h o s 4

. 3 8 1

. 8 7 7

. 5 8 1

. 4 0

. 0 8 9

- - –

2 3 1 6 1 6 0 2 T e bu pi ri m p h o s 5

. 8 8 4

. 3 7 8

. 5 8 6

. 4 0

. 0 9 0

- - –

2 8 8 2 6 6 2 D i m e t h oat e 2 1

. 0 1 7

. 6 0

. 0 2 7

. 1 0

. 5 7 0

- - E

3 0 6 1 6 1 0 T r i b u p h o s 6

. 7 5 3

. 9 4 7

. 2 5 0

. 1

- 0

. 0 7 0

- - E

7 1 3 4 3 5 7 bet a

- E n dos u l f a n 5

. 7 9 8

. 5 9 2

. 7 7 8

. 8

- 1

. 7 1 4 4 E

7 6 6 1 6 0 6 T e f l u t h r i n 3

. 9 4 3

. 4 3 9

. 5 4 7

. 4

- 0

. 1 4 8 2 7 E

8 3 3 8 4 5 4 D i crot oph os 6

. 1 1 8

. 2 1 2

. 1 2 2

. 2

- 0

. 1 4 2

- - E

9 3 6 1 5 9 3 Iprodi on e 4

. 3 8 0

. 0 7 5

. 7 7 4

. 6

- 0

. 6 6 1 7 E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 2

. 0 2 9

. 8 2 7

. 8 2 3

. 5

- 0

. 7 0 0 3 E

1 1 4 6 1 5 8 6 C y perm et h r i n 1 1

. 6 5 2

. 6 4 1

. 0 5 3

. 0

- 0

. 7 8 4 1 5 E

1 1 5 3 8 7 1 6 S u l p rof o s 7

. 8 6 1

. 3 5 3

. 5 6 2

. 3

- 0

. 0 6 1

- - E

1 2 5 6 1 6 0 1 Ph os m e t 7

. 4 2 7

. 0 1 9

. 6 2 7

. 0

- 4

. 5 2 5 2 E

1 2 9 6 1 5 8 5 C y f l u t h r i n 1 0

. 7 5 1

. 6 4 0

. 9 5 2

. 2

- 0

. 7 5 0 1 5 E

1 3 1 6 1 5 8 0 Bi f e n t h r i n 4

. 0 3 7

. 2 3 3

. 3 3 7

. 8

- 0

. 0 8 4

- - E

2 3 0 6 1 6 0 5 S u l f ot e p p 4

. 1 7 9

. 2 7 5

. 1 7 9

. 8

- 0

. 4 9 6 9 E

2 3 2 6 1 6 0 7 T e m e ph os 1 7

. 0

– – – – – E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 3.7 89.8 86.2 93.1

- 0 .036

- - –

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 5.7 88.8 83.1 94.5 0.002

- - –

1 T e r b ut hy l a z i ne a n d t e m e p h o s w e r e no t i n c l ud e d i n ho l d i ng-t i m e e x p e r i m e nt s.

56 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr yT a b l e 16. Statis tic a l data us ed to deter m i ne es tim a ted holding tim e of degr adates in pes tic i de- gr ade w a ter

m a intained at 4 degr ees Cels ius

[A n a ly tes w ith h o ld in g tim es less th an 4 d a y s sh o w n

in b o l d

. Reag en t- w a ter sam p les w e re f o rtif ied at 0

. 1 m i cro g ram p e r

liter, an d f o u r rep licate sam p les w e re ex tracted an d p r ep ared f o r an aly s is o n d a y s 0

, 1

, 3

, 7

, 1 4

, an d 2 8

. P

- Co d e , Natio n a l

Water In f o rm ation S y s t em param e ter code; d , tolerable ran g e of v a riation f

r om m ean recov e ry , in percen t; Mean –d, m ean

reco v e ry o n d a y 0 m i n u s d ; In tercep t, in tercep t o f lin ear f it to h o ld in g

- tim e resu lts; Slo p e , slo p e o f lin ear f it to h o ld in g

- ti me

resu lts;

-- , es tim ated h o ldin g tim e g r eater th an 28 day s becau s e com pou n d did n o t decreas e in con cen tration ov er 28- day tes t

peri od;

–, n o t ap p licab le; E, estim ated q u alif ier rem a rk ]

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) Inte r c e p t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

D e gr adat es

1 0 0 2 6 1 6 1 5 2- [2- E t h y l

- 6

- m _pan o l 9

. 3 7 2

. 3 6 3

. 0 7 3

. 3 0

. 1 0 4

- - –

1 0 0 7 6 1 6 1 8 2- C h loro- 2 ,6

- d

_ i l i d e 3

. 2 8 6

. 1 8 2

. 9 8 6

. 3 0

. 0 4 2

- - –

1 0 0 8 6 1 6 6 5 4- (H y d rox y m e t h _h al i n 1 3

. 5 1 0 6

. 5 9 2

. 9 1 0 5

. 1 0

. 0 1 8

- - –

1 0 1 6 6 1 6 7 4 T e rbu f os

- O

- a n a _l f o n e 1 2

. 4 5 9

. 6 4 7

. 2 5 2

. 4

- 0

. 3 3 2

- - –

1 0 3 3 6 1 6 2 5 3,4- Dich loroan ilin e 14. 7 8 5

. 3 7 0

. 7 8 9

. 9 0

. 2 5 8

- - –

1 0 4 3 6 1 6 2 9 3- Ph en ox y b en zy _coh ol 4

. 2 7 4

. 0 6 9

. 8 7 6

. 2

- 0

. 0 2 2

- - –

1 0 4 4 7 9 8 4 2 c

- M et h y l

- 3- (2,_y l at e 4

. 9 9 0

. 2 8 5

. 3 8 9

. 5

- 0

. 0 8 3

- - –

1 0 4 4 7 9 8 4 3 t

- M et h y l

- 3- (2,_y l at e 7

. 0 9 0

. 8 8 3

. 7 9 0

. 0

- 0

. 0 3 0

- - –

1 0 4 9 6 1 6 6 3 Paraox on

- e t h y l 1 5

. 0 6 5

. 9 6 1

. 0 6 6

. 4 0

. 0 8 5

- - –

1 0 6 0 6 1 6 5 2 Mal a ox on 9

. 1 6 7

. 4 5 8

. 3 5 4

. 0

- 0

. 4 0 9 2 3

–

1 0 6 2 6 1 6 3 7 2- (4- t ert

- bu t y _x an ol 9

. 9 8 0

. 7 7 0

. 9 8 1

. 2

- 0

. 0 0 2

- - –

1 0 6 7 6 1 6 4 0 D i s u l f ot on s u l f on e 5

. 8 5 3

. 5 4 7

. 7 5 0

. 9

- 0

. 1 9 4 3 0

–

1 0 7 1 6 1 6 4 2 En dos u l f a n et h e r 4

. 7 1 0 3

. 9 9 9

. 2 1 0 0

. 6 0

. 0 1 6

- - –

1 0 7 1 6 1 5 9 0 En dos u l f a n s u l f at e 1 5

. 7 9 3

. 2 8 7

. 5 9 2

. 3 0

. 0 3 4

- - –

1 0 7 6 6 1 6 7 2 T e f l u t h r i n m e t

_ 2 9 1 2 ] 4

. 2 7 0

. 1 6 5

. 9 7 0

. 3

- 0

. 0 7 4

- - –

1 0 9 3 6 1 6 2 7 3,5- Dich loroan ilin e 11. 2 8 8

. 7 7 7

. 5 9 2

. 1 0

. 2 3 0

- - –

1 0 9 9 6 1 6 1 4 2,5- Dich loroan ilin e 8. 8 8 1

. 2 7 2

. 4 8 3

. 1 0

. 1 2 0

- - –

1 1 2 4 6 1 6 6 0 O

- Et h y l

- O

- m e t h _i oat e 8

. 3 8 0

. 9 7 2

. 6 8 2

. 0 0

. 1 5 6

- - –

1 1 2 6 6 1 6 4 5 F e n a m i ph os s u l f on e 9

. 3 7 2

. 0 6 2

. 7 6 8

. 2

- 0

. 1 4 0

- - –

1 2 3 1 6 1 6 6 9 T e bu pi ri m p h o s

, _l og u e 4

. 4 7 5

. 9 7 1

. 5 7 6

. 1

- 0

. 0 5 8

- - –

1 0 0 2 6 1 6 2 0 2- Eth y l- 6- m e th _ilin e 3

. 4 8 9

. 7 8 6

. 3 9 3

. 0 0

. 1 6 6

- - E

1 0 1 2 6 1 6 3 6 C h l o rpy r i f

os

, _n al og 8

. 8 5 6

. 7 4 7

. 8 5 5

. 6 0

. 2 6 6

- - E

1 0 1 3 6 1 6 1 7 2- A m i n o- N

- i s op_am i d e 1 5

. 4 5 0

. 8 3 5

. 3 5 4

. 6 0

. 2 8 9

- - E

1 0 1 4 6 1 6 6 4 Paraox on

- m et h y l 3

. 9 7 9

. 7 7 5

. 8 7 6

. 0 0

. 3 5 9

- - E

1 0 1 5 6 1 6 3 3 4- C h l o ro- 2

- m et _h en ol 1 7

. 2 5 8

. 0 4 0

. 8 6 5

. 3 0

. 3 9 3

- - E

1 0 2 4 6 1 6 3 0 3- T r if lu orom et_ilin e 5

. 3 5 2

. 0 4 6

. 7 5 3

. 4 0

. 1 0 8

- - E

1 0 3 2 4 9 2 9 5 1- N a ph t h ol 1 8

. 0 9 7

. 8 7 9

. 8 1 1 3

. 5 0

. 7 0 6

- - E

1 0 3 2 6 1 6 1 1 1,4- N a ph t h aqu i n o n e 1 8

. 2 4 2

. 2 2 4

. 1 3 9

. 4 0

. 0 0 2

- - E

1 0 3 4 6 1 6 6 6 Ph orat e ox on 1 0

. 3 7 2

. 2 6 2

. 0 7 0

. 8

- 1

. 3 7 1 8 E

1 0 5 3 6 1 6 3 5 A z i n ph os

- m et h y l

- ox on 2 0

. 0 3 5

. 1 1 5

. 0 3 7

. 2 0

. 3 8 9

- - E

1 0 5 4 6 1 6 4 9 F o n o f o s

, ox y g e_n a l o g 3

. 4 6 5

. 0 6 1

. 7 6 6

. 8 0

. 1 8 1

- - E

1 0 6 7 6 1 6 4 1 D i s u l f ot on s u l f ox i d e 1 2

. 2 1 2 1

. 4 1 0 9

. 3 1 2 2

. 7 0

. 4 0 9

- - E

1 0 7 6 6 1 6 7 1 T e f l u t h r i n m e t

_ 9 3 6 4 ] 6

. 0 5 5

. 3 4 9

. 3 5 4

. 8

- 0

. 2 5 0 2 4 E

1 1 0 1 6 1 6 3 1 4,4'

- D i c h l orob_en o n e 4

. 6 6 9

. 0 6 4

. 4 7 1

. 8 0

. 1 0 4

- - E

Final Method Validation 57T a b l e 16. Statis tic a l data us ed to deter m i ne es tim a ted holding tim e of degr adates in pes tic i de- gr ade

w a ter m a intained at 4 degr ees Cels ius

— Continued

Ra nk P

- Code S hor t na me d

( p ercen t ) M ean

reco v e ry

da y 0

( p ercen t ) M ean

– d

( p ercen t ) Inte r c e p t

( p ercen t ) S l ope Holding

time

( d ay s) Remark

c ode

1 1 0 5 6 1 6 3 4 4- C h l o roben z y l _l f o n e 1 2

. 8 6 1

. 7 4 8

. 9 6 2

. 3 0

. 0 6 4

- - E

1 1 2 5 6 1 6 6 8 Ph os m e t ox on 1 7

. 9 7

. 4 0

. 0 9

. 7 0

. 0 0 3

- - E

1 1 2 6 6 1 6 4 6 F e n a m i ph os s u l f ox i d e 5

. 0 9

. 9 4

. 9 1 1

. 2

- 0

. 0 3 4

- - E

1 1 3 4 6 1 6 4 4 Et h i on m o n o x o n 3

. 8 5 5

. 0 5 1

. 2 5 4

. 4 0

. 0 2 1

- - E

1 1 5 3 3 8 7 7 5 D i ch l o rv os 1 7

. 1 3 5

. 3 2 8

. 2 3 3

. 1 0

. 0 5 5

- - E

1 2 2 7 6 1 6 4 7 F e n t h i on s u l f ox i d e 6

. 2 6 3

. 8 5 7

. 7 6 4

. 7 0

. 0 5 7

- - E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 9.0 100.8 91.8 98.4

- 0 .068

-- –

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 5.0 85.9 80.9 86.5

- 0 .104

-- –

1 Dich lorv os , en dos u l f a n

s u lf ate, an d paraox on

- e th y l w e re an aly zed in paren t f

o rtif ication m i x t u r e.

T a b l e 17. Bias and var i ability data f r om r eagent- w ater

- s et s a m p les f o r t if ied w i th analy t es at low ( 0 .1

m i c r ogr am per liter ) c onc entr a tions and analy z ed dur ing Mar c h thr ough Dec e m ber , 1999

[A n a l y t e s w i t h m e di an recov e ri es l e s s t h an 60 percen t or g r eat er t h an 120 percen t

, or h a v i n g a rel a t i v e F

p s eu d o s ig m a g r eater th an 2 5 p e rcen t are rep o r ted w ith an estim ated (E) rem a rk co d e . A d d itio n a l an aly t es w ith sh o r t

h o ldin g tim es are als o reported w ith an es tim ated rem a rk co d e . Ran k

, n a tio n a l ap p licatio n an d u s e ran k o f p e sticid e;

P

- Co d e , Natio n a l W a ter In f o rm atio n Sy stem p a ram e ter co d e ; co n c ., co n cen tratio n ; μg /L , m i cro g ram p e r liter; F- p s eu

, F- ps eu dos ig m a (in t erqu artile ran g e /1.349); R e l F- ps eu , re lativ e F- ps eu dos ig m a ; –, n o t applicable; E, es tim ated

rem a rk code]

Ra nk P

- Code S hor t na me Me d i a n

c onc

. (μg/L) F-ps e u

(μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u ( p ercen t ) Count Remark

c ode

Pa rent p e sticid es

6 3 0 4 0 3 6 Prom et ry n 0

. 0 8 9 0

. 0 0 9 8 9

. 3 1 0

. 5 4 9

–

6 9 6 1 6 0 3 Prof en of os 0

. 0 7 3 0

. 0 1 1 7 2

. 9 1 4

. 9 4 9

–

7 1 3 4 3 6 2 al pha

- E n dos u l f a n 0

. 0 8 1 0

. 0 0 8 8 1

. 3 9

. 8 4 9

–

7 5 6 1 5 9 6 Met a l a x y l 0

. 0 9 5 0

. 0 1 0 9 5

. 1 1 0

. 7 4 9

–

1 0 6 6 1 6 0 0 O x y f l u orf e n 0

. 0 6 1 0

. 0 0 7 6 1

. 4 1 1

. 0 4 9

–

1 0 8 7 9 8 4 6 cis

- P ropi con azol e 0

. 0 8 3 0

. 0 1 0 8 2

. 6 1 2

. 1 4 9

–

1 1 0 7 9 8 4 7 t r ans

- P ropi con azol e 0

. 0 8 1 0

. 0 0 9 8 1

. 4 1 1

. 6 4 9

–

1 2 1 6 1 5 9 9 My cl obu t a n i l 0

. 0 8 0 0

. 0 0 7 8 0

. 3 9

. 2 4 9

–

1 2 6 6 1 5 9 1 F e n a m i ph os 0

. 0 7 0 0

. 0 0 6 7 0

. 5 9

. 2 4 9

–

1 2 7 0 4 0 2 5 H e x azi n o n e 0

. 0 6 0 0

. 0 0 7 6 0

. 3 1 2

. 0 4 9

–

1 2 8 0 4 0 3 1 C y cl oat e 0

. 0 8 9 0

. 0 0 6 8 9

. 3 6

. 3 4 9

–

1 3 2 6 1 5 9 8 Met h i d at h i on 0

. 0 7 7 0

. 0 1 0 7 6

. 9 1 3

. 1 4 9

–

1 3 4 8 2 3 4 6 Et h i on 0

. 0 6 4 0

. 0 1 1 6 4

. 2 1 6

. 5 4 9

–

2 1 1 7 9 8 4 4 (E)- D i m e t h om orph 0

. 0 7 6 0

. 0 1 1 7 5

. 8 1 5

. 0 4 9

–

2 1 2 7 9 8 4 5 (Z )- D i m e t h om orph 0

. 0 7 3 0

. 0 1 0 7 2

. 8 1 4

. 0 4 9

–

2 2 0 0 4 0 2 2 T e rbu t h y l azi n e 0

. 0 9 7 0

. 0 0 8 9 6

. 7 8

. 0 1 8

–

2 2 5 6 1 5 9 2 F l u m et ral i n 0

. 0 6 6 0

. 0 1 0 6 6

. 4 1 5

. 7 4 9

–

2 2 7 3 8 8 0 1 F e n t h i on 0

. 0 8 7 0

. 0 1 1 8 6

. 8 1 2

. 4 4 9

–

58 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr yT a b l e 17. Bias and var i ability data f r om r eagent- w ater

- s et s a m p les f o r t if ied w i th analy t es at low

( 0 .1 m i c r ogr am per liter ) c onc entr a tions and analy z ed dur ing Mar c h thr ough Dec e m ber , 1999—Continued

Ra nk P

- Code S hor t na me Me d i a n

c onc

. (μg/L) F-ps e u

(μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) Count Remark

c ode

2 2 8 6 1 5 9 4 Is of en

ph os 0

. 0 8 6 0

. 0 0 8 8 5

. 6 9

. 7 4 9

–

2 2 9 6 1 6 0 4 Propet a m p h o s 0

. 0 8 7 0

. 0 1 0 8 6

. 7 1 1

. 5 4 9

–

2 3 1 6 1 6 0 2 T e bu pi ri m p h o s 0

. 0 8 6 0

. 0 0 8 8 6

. 4 8

. 7 4 9

–

2 8 8 2 6 6 2 D i m e t h oat e 0

. 0 3 5 0

. 0 0 7 3 5

. 3 2 1

. 2 4 9 E

3 0 6 1 6 1 0 T r i b u p h o s 0

. 0 4 4 0

. 0 0 8 4 3

. 7 1 7

. 4 4 9 E

7 1 3 4 3 5 7 bet a

- E n dos u l f a n 0

. 0 9 1 0

. 0 0 9 9 1

. 0 9

. 5 4 9 E

7 6 6 1 6 0 6 T e f l u t h r i n 0

. 0 3 2 0

. 0 0 6 3 2

. 4 1 7

. 7 4 9 E

8 3 3 8 4 5 4 D i crot oph os 0

. 0 2 8 0

. 0 0 6 2 8

. 1 2 2

. 0 4 9 E

9 3 6 1 5 9 3 Iprodi on e 0

. 0 7 4 0

. 0 3 4 7 4

. 3 4 6

. 1 4 9 E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 0

. 0 2 1 0

. 0 0 6 2 0

. 9 3 0

. 0 4 9 E

1 1 4 6 1 5 8 6 C y perm et h r i n 0

. 0 4 7 0

. 0 1 4 4 6

. 6 3 0

. 9 4 9 E

1 1 5 3 8 7 1 6 S u l p rof o s 0

. 0 6 6 0

. 0 1 3 6 6

. 3 1 9

. 9 4 9 E

1 2 5 6 1 6 0 1 Ph os m e t 0

. 0 2 0 0

. 0 2 1 2 0

. 1 1 0 4

. 1 4 9 E

1 2 9 6 1 5 8 5 C y f l u t h r i n 0

. 0 4 4 0

. 0 1 0 4 4

. 3 2 3

. 3 4 9 E

1 3 1 6 1 5 8 0 Bi f e n t h r i n 0

. 0 2 7 0

. 0 0 5 2 7

. 3 1 9

. 5 4 9 E

2 3 0 6 1 6 0 5 S u l f ot e p p 0

. 0 8 6 0

. 0 0 7 8 6

. 1 8

. 0 4 9 E

2 3 2 6 1 6 0 7 T e m e ph os 0

. 0 3 4 0

. 0 1 5 3 3

. 9 4 4

. 5 4 9 E

D e gr adat es

1 0 0 2 6 1 6 1 5 2- [2- E t h y l

- 6

- m _pan o l 0

. 0 8 4 0

. 0 0 9 8 4

. 3 1 0

. 7 7 4

–

1 0 0 7 6 1 6 1 8 2- C h loro- 2 ,6

- d

_ i l i d e 0

. 0 8 7 0. 0 1 1 8 6

. 6 1 2

. 1 7 4

–

1 0 0 8 6 1 6 6 5 4- (H y d rox y m e t h _h al i n 0

. 0 8 1 0

. 0 1 9 8 0

. 6 2 3

. 6 7 4

–

1 0 1 6 6 1 6 7 4 T e rbu f os

- O

- a n a _l f o n e 0

. 0 7 3 0

. 0 1 2 7 2

. 6 1 6

. 8 4 9

–

1 0 3 3 6 1 6 2 5 3,4- Dich loroan ilin e 0

. 0 8 1 0

. 0 1 4 8 0

. 6 1 7

. 6 7 4

–

1 0 4 3 6 1 6 2 9 3- Ph en ox y b en zy _coh ol 0

. 0 7 4 0

. 0 1 0 7 4

. 3 1 3

. 6 7 4

–

1 0 4 4 7 9 8 4 2 c

- M et h y l

- 3- (2,_y l at e 0

. 0 8 5 0

. 0 0 7 8 5

. 0 8

. 8 7 4

–

1 0 4 4 7 9 8 4 3 t

- M et h y l

- 3- (2,_y l at e 0

. 0 9 0 0

. 0 0 7 9 0

. 4 7

. 6 7 4

–

1 0 4 9 6 1 6 6 3 Paraox on

- e t h y l 0

. 0 8 5 0

. 0 1 1 8 4

. 9 1 3

. 4 4 9

–

1 0 6 0 6 1 6 5 2 Mal a ox on 0

. 0 7 6 0

. 0 1 5 7 6

. 4 2 0

. 0 7 4

–

1 0 6 2 6 1 6 3 7 2- (4- t ert

- bu t y _x an ol 0

. 0 8 6 0

. 0 1 0 8 6

. 1 1 1

. 3 7 4

–

1 0 6 7 6 1 6 4 0 D i s u l f ot on s u l f on e 0

. 0 7 3 0

. 0 1 0 7 2

. 7 1 3

. 4 7 4

–

1 0 7 1 6 1 6 4 2 En dos u l f a n et h e r 0

. 1 0 2 0

. 0 1 1 1 0 1

. 6 1 1

. 1 7 4

–

1 0 7 1 6 1 5 9 0 En dos u l f a n s u l f at e 0

. 0 9 1 0

. 0 0 7 9 1

. 3 7

. 4 4 9

–

1 0 7 6 6 1 6 7 2 T e f l u t h r i n m e t

_ 2 9 1 2 ] 0

. 0 6 0 0

. 0 1 0 6 0

. 1 1 6

. 8 7 4

–

1 0 9 3 6 1 6 2 7 3,5- Dich loroan ilin e 0

. 0 9 1 0

. 0 1 1 9 1

. 2 1 2

. 6 7 4

–

1 0 9 9 6 1 6 1 4 2,5- Dich loroan ilin e 0

. 0 7 8 0

. 0 1 4 7 7

. 8 1 7

. 5 7 4

–

1 1 2 4 6 1 6 6 0 O

- Et h y l

- O

- m e t h _i oat e 0

. 0 8 5 0

. 0 0 9 8 5

. 3 1 0

. 1 7 4

–

1 2 3 1 6 1 6 6 9 T e bu pi ri m p h o s

, _l og u e 0

. 0 7 6 0

. 0 1 2 7 6

. 4 1 5

. 4 7 4

–

1 0 0 2 6 1 6 2 0 2- Eth y l- 6- m e th _ilin e 0

. 0 9 6 0

. 0 1 1 9 6

. 1 1 1

. 1 7 4 E

1 0 1 2 6 1 6 3 6 C h l o rpy r i f

os

, _n al og 0

. 0 3 9 0

. 0 2 3 3 8

. 8 5 9

. 5 7 4 E

1 0 1 3 6 1 6 1 7 2- A m i n o- N

- i s op_am i d e 0

. 0 5 5 0

. 0 1 2 5 4

. 7 2 1

. 9 7 4 E

1 0 1 4 6 1 6 6 4 Paraox on

- m et h y l 0

. 0 7 2 0

. 0 1 4 7 2

. 4 1 9

. 9 7 4 E

1 0 1 5 6 1 6 3 3 4- C h l o ro- 2

- m et _h en ol 0

. 0 6 0 0

. 0 2 1 6 0

. 4 3 4

. 1 7 4 E

Final Method Validation 59T a b l e 17. Bias and var i ability data f r om r eagent- w ater

- s et s a m p les f o r t if ied w i th analy t es at low

( 0 .1 m i c r ogr am per liter ) c onc entr a tions and analy z ed dur ing Mar c h thr ough Dec e m ber , 1999—Continued

Ra nk P

- Code S hor t na me Me d i a n

c onc

. (μg/L) F-ps e u

(μg/L) Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) Count Remark

c ode

1 0 2 4 6 1 6 3 0 3- T r if lu orom et_ilin e 0

. 0 4 1 0

. 0 1 5 4 1

. 1 3 5

. 9 7 4 E

1 0 3 2 4 9 2 9 5 1- N a ph t h ol 0

. 0 6 1 0

. 0 5 5 6 0

. 7 9 0

. 9 7 3 E

1 0 3 2 6 1 6 1 1 1,4- N a ph t h aqu i n o n e 0

. 0 3 4 0

. 0 1 5 3 4

. 2 4 4

. 3 7 4 E

1 0 3 4 6 1 6 6 6 Ph orat e ox on 0

. 0 7 8 0

. 0 1 2 7 7

. 5 1 5

. 3 7 4 E

1 0 5 3 6 1 6 3 5 A z i n ph os

- m et h y l

- ox on 0

. 0 4 4 0

. 0 2 0 4 4

. 5 4 5

. 6 7 2 E

1 0 5 4 6 1 6 4 9 F o n o f o s

, ox y g e_n a l o g 0

. 0 7 7 0

. 0 0 7 7 7

. 0 8

. 6 4 9 E

1 0 6 7 6 1 6 4 1 D i s u l f ot on s u l f ox i d e 0

. 1 2 5 0

. 0 2 1 1 2 5

. 0 1 6

. 8 4 9 E

1 0 7 6 6 1 6 7 1 T e f l u t h r i n m e t

_ 9 3 6 4 ] 0

. 0 3 4 0

. 0 0 8 3 3

. 7 2 4

. 2 7 4 E

1 1 0 1 6 1 6 3 1 4,4'

- D i c h l orob_en o n e 0

. 0 7 6 0

. 0 1 0 7 6

. 5 1 2

. 7 7 4 E

1 1 0 5 6 1 6 3 4 4- C h l o roben z y l _l f o n e 0

. 0 5 9 0

. 0 1 1 5 9

. 2 1 7

. 8 4 9 E

1 1 2 5 6 1 6 6 8 Ph os m e t ox on 0

. 0 1 6 0

. 0 1 3 1 5

. 6 8 6

. 3 4 9 E

1 1 2 6 6 1 6 4 6 F e n a m i ph os s u l f ox i d e 0

. 0 2 2 0

. 0 1 0 2 1

. 9 4 6

. 5 4 8 E

1 1 3 4 6 1 6 4 4 Et h i on m o n o x o n 0

. 0 5 9 0

. 0 1 5 5 8

. 7 2 6

. 3 7 4 E

1 1 5 3 3 8 7 7 5 D i ch l o rv os 0

. 0 5 0 0

. 0 1 6 4 9

. 8 3 1

. 4 4 9 E

1 2 2 7 6 1 6 4 7 F e n t h i on s u l f ox i d e 0

. 0 6 4 0

. 0 2 6 6 3

. 9 4 1

. 0 7 4 E

S u r r ogat es

9 9 2 2 3 D i azi n o n

- d 10 , _og at e 0.094 0.010 94.4 10.7 74

–

9 9 2 2 4 al pha -H CH

- d 6 , _og at e 0.092 0.013 91.9 14.5 74

–

Figur e 2

. Bias and var i ability data f r om r eagent- w ater

- s et s a m p les f o r t if ied w i th analy t es at low ( 0 .1

m i c r ogr am per liter ) c onc entr a tions and pr epar ed dur ing Mar c h thr ough Dec e m ber , 1999. Line s how s r a tio of

F

- ps eudos igm a to m edian of 0.25, c o m par able to an F

- ps eudos igm a of 25 per c ent ( data f r om table 17)

.

60 D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Wate r

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y

### pr oble m s in a ll ma tr ic e s a nd a ll

c onc e n tr a tions or ha d shor t holding time s.

The s e a n a l y t e s a r e r e por te d with a n e s tima te d

r e ma r k

c ode to a l e r t the da ta use r to the

g r eat er uncert a i n t y associ at ed wi t h t h e

qua ntita tive r e sults. The f o r tif ie d r e a g e n twa te r

- s e t sa mple r e sults we r e use d to

c h a r a c t e r ize long

- t e r m bia s a nd va r i a b ility

problems (table 17). Cr ite r i a f

o r

qua lif ic a tion

a s e s tima te d we r e me dia n r e c ove r y

le ss tha n

60 percent or g r eater than 120 percent, or

relative F

- pseudosig ma g r eater than 25

percent. I n addition, the holding -time results

were used to qualify analy t es with short

holding time s. Cr ite r i a use d we r e holding

time s in wa te r le ss tha n 4 da y s or holding

time s on the dr y

SPE c o lumn le ss tha n 7 da y s

.

The a n a l y t e s qua lif ie d with " e stima te d"

are listed in table 18. Parent pesticides

qua lif ie d with e s tima te d r e ma r k

c ode s

because of m e di an recovery l e ss t h an 60

percent were dimethoate , tribuphos, tefluthrin,

dichrotophos, cy fluthri n, and bifenthrin.

De g r a d a t e s qua lif ie d with e s tima te d r e ma r k

codes because of l o w m e di an recovery were

2-amino-N-isop_amide, 4- chlorobenz y l _lfone

and tefluthrin met_9364, but disulfoton

sul f ox i d e was qual i f i e d because of hi g h

recovery . I p rodione wa s qua lif ie d with

estimated remark code because of relative F

pseudosig ma g r eater than 25 percent.

Cy halothrin, cy permethrin, phosmet, and

temephos were characteriz ed by low recovery

a nd hig h va r i a b ility . De g r a d a t e a n a l y t e s with

relative F

- pseudosig ma g r eater than 25

percent included 4-chloro-2-met_henol; 1-

naphthol and fenthion sulfox ide. Deg r adates

charact eri z ed by l o w recovery and hi g h

variability include d 1,4-naphthaquinone;

c h lor p y r if os, _na log ; 3- tr if luor ome t _iline ;

az inphos-methy l-ox on; phosmet ox on;

fenamiphos sulfox ide; ethion monox on; and

dichlorvos.

Ana l y t e s with holding time s in wa te r

less than or equal to 4 day s included beta

endosulfan, cy halothrin, and phosmet. None

of the deg r adate compounds had estimated

holding time s le ss tha n or e qua l to 4 da y s

. Sulprofos and sulfotepp are org a nothiophosphate pesticides that have short holding

times on the dry SPE column, even thoug h

the y a r e a ppa r e ntly sta b le f o r

a

long e r time in

wa te r

. Ox ida tive de g r a d a tion c a n c a u se loss

of org a nothiophosphate pesticides, and it

would be useful to analy z e ox idative

deg r adat es of t h ese t w o pest i c i d es i n t h e

sa mple s to de te r mine if the s e pe stic ide s we r e

lost during storag e on the SPE column.

Simila r l y

, a numbe r of de g r a d a t e s a ppe a r to

ha ve shor t holding time s on the dr y

SPE

c o lumn, inc l uding 2- e t hy l- 6- me th_iline ;

paraox on-methy l; 1-na phthol; phorate ox on;

chlorpy r ifos, _nalog ; and 4,4'

- dichlorob_enone. Chlorpy r ifos, _nalog

appears to deg r ade quickly on the SPE

column, and this mig ht ex plain hig h

va r i a b ility f

o r

this de g r a d a t e in the va lida tion

e x pe r ime nts a nd f o r tif ie d r e a g e n t- wa te r

sa mple s.

OTHE R CONS IDE R A T IONS

A u toma ti on

The method is ideally suited for

automation by using laboratory sy stems to

prepare samples. The method, with minor

modifications, has been successfully used

with an AutoTrace S P E W o rkstation. An

ex ample of the procedur e and parameter setup

used wi t h t h e Aut o Trace S P E W o rkst at i on i s

shown in Supplement A.

On- S it e Ext r act ion

The method also can be used with an

optional on-site ex trac tion procedure, which

a llows sa mple s to be c o llected and processed at

remote locations. This procedure reduces

pot ent i a l probl em s for som e anal y t es t h at ex ceed

the e s tima te d pr e

- e x tr a c tion holding

- time limit in

water of 4 day s and a voids complications and

O t her Considerations 61T a b l e 18. Analy t es qualif ied as es tim a ted c onc entr a tion bec aus e of lar ge bias and var i ability

r e s u lts of f o r t if ied r eagent- w ater

- s et s a m p les ( t able 17) or s hor t holding- tim e r e s u lts ( t ables 13–

16) . Cr iter ia f o r es tim a tion w e r e m edian r e c o ver y les s than 60 per c ent, or gr eater than 120

per c ent, r e lative F

- ps eudos igm a m o r e than 25 per c ent, holding tim e in w a ter les s than 4 day s

, or

holding tim e on s o lid- phas e- ex tr ac tion c o lum n les s than 7 day s

.

[Ran k

, n a tio n a l ap p licatio n an d u s e ran k o f p e sticid e; P

- Co d e , Natio n a l W a ter In f o rm atio n Sy stem p a ram e ter

co d e ; Rel F- p s eu , Relativ e F- p s eu d o s ig m a ; d , d a y ; SP E, so lid

- p h a se ex tractio n ; - - , n o t w ith in criteria; E,

es tim ated rem a rk code]

Ra nk P

– Code S hor t na me Me d i a n

reco v e ry

( p ercen t ) Rel

F-ps e u

( p ercen t ) Wa te r

hold time

( d

) SPE

hold time

( d

) Remark

c ode

Pa rent p e sticid es

2 8 8 2 6 6 2 D i m e t h oat e 3 5

. 3

- - - - - - E

3 0 6 1 6 1 0 T r i b u p h o s 4 3

. 7

- - - - - - E

7 1 3 4 3 5 7 bet a -E nd o s ul fa n

- - - - 4

- - E

7 6 6 1 6 0 6 T e f l u t h r i n 3 2

. 4

- - - - - - E

8 3 3 8 4 5 4 D i crot oph os 2 8

. 1

- - - - - - E

9 3 6 1 5 9 3 Iprodi on e

- - 4 6

. 1

- - - - E

1 0 2 6 1 5 9 5 C y h a l o t h ri n 2 0

. 9 3 0

. 0 3

- - E

1 1 4 6 1 5 8 6 C y perm et h r i n 4 6

. 6 3 0

. 9

- - - - E

1 1 5 3 8 7 1 6 S u l p rof o s

- - - - - - 6 E

1 2 5 6 1 6 0 1 Ph os m e t 2 0

. 1 1 0 4

. 1 2

- - E

1 2 9 6 1 5 8 5 C y f l u t h r i n 4 4

. 3

- - - - - - E

1 3 1 6 1 5 8 0 Bi f e n t h r i n 2 7

. 3

- - - - - - E

2 3 0 6 1 6 0 5 S u l f ot e p p

- - - - - - 4 E

2 3 2 6 1 6 0 7 T e m e ph os 3 3

. 9 4 4

. 5

- - - - E

D e gr adat es

1 0 0 2 6 1 6 2 0 2- Eth y l- 6- m e th _ilin e

- - - - - - 5 E

1 0 1 2 6 1 6 3 6 C h l o rpy r i f

os

, _n al og 3 8

. 8 5 9

. 5

- - 1 E

1 0 1 3 6 1 6 1 7 2- A m i n o- N

- i s op_am i d e 5 4

. 7

- - - - - - E

1 0 1 4 6 1 6 6 4 Paraox on

- m et h y l

- - - - - - 5 E

1 0 1 5 6 1 6 3 3 4- C h l o ro- 2

- m et _h en ol

- - 3 4

. 1

- - - - E

1 0 2 4 6 1 6 3 0 3- T r if lu orom et_ilin e 4 1

. 1 3 5

. 9

- - - - E

1 0 3 2 4 9 2 9 5 1- N a ph t h ol

- - 9 0

. 9

- - 4 E

1 0 3 4 6 1 6 6 6 Ph orat e ox on

- - - - - - 5 E

1 0 5 3 6 1 6 3 5 A z i n ph os

- m et h y l

- ox on 4 4

. 5 4 5

. 6

- - - - E

1 0 5 4 6 1 6 4 9 F o n o f o s

, ox y g e_n a l o g

- - - - - - 3 E

1 0 6 7 6 1 6 4 1 D i s u l f ot on s u l f ox i d e 1 2 5

. 0 1 6

. 8

- - - - E

1 0 7 6 6 1 6 7 1 T e f l u t h r i n m e t

_ 9 3 6 4 ] 3 3

. 7

- - - - - - E

1 1 0 1 6 1 6 3 1 4,4'

- D i c h l orob_en o n e

- - - - - - 5 E

1 1 0 5 6 1 6 3 4 4- C h l o roben z y l _l f o n e 5 9

. 2

- - - - - - E

1 1 2 5 6 1 6 6 8 Ph os m e t ox on 1 5

. 6 8 6

. 3

- - - - E

1 1 2 6 6 1 6 4 6 F e n a m i ph os s u l f ox i d e 2 1

. 9 4 6

. 5

- - - - E

1 1 3 4 6 1 6 4 4 Et h i on m o n o x o n 5 8

. 7 2 6

. 3

- - - - E

1 0 3 2 6 1 6 1 1 1,4- N a ph t h aqu i n o n e 3 4

. 2 4 4

. 3

- - - - E

1 1 5 3 3 8 7 7 5 D i ch l o rv os 4 9

. 8 3 1

. 4

- - - - E

1 2 2 7 6 1 6 4 7 F e n t h i on s u l f ox i d e

- - 4 1

. 0

- - - - E

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 62

### ex pense of overnig ht shipping of samples to

the la bor a t or y

. A holding

- time study on da mp

SPE c o lumns a pplic a b le to on- site e x tr a c tion

has not been conducted. I n structions for onsite processing are listed in Supplement B

.

CONCLUS IONS

Solid- pha se e x tr a c tion with de te r mina

tion by g a s chromatog r aphy/mass spectrome tr y

is shown to be a se nsitive a nd r e lia ble

method for the determination of low concentrations of a broad ra ng e of pesticides and

de g r a d a t e s in wa te r sa mple s. This r e por t

presents a new method for routine analy s is of

21 parent pesticides and 20 pesticide

de g r a d a t e s in f ilte r e d na tur a l- wa te r sa mple s.

Estimated method detec tion limits rang e from

0.001 to 0.057 μg /L . Another 14 parent

pesticides and 20 pesticide deg r adates

demonstrated median r ecoveries less than 60

percent or g r eater than 120 percent, or had

relative F

- pseudosig ma mo re than 25 percent,

or

holding time s le ss tha n 4 da y s in wa te r or 7

day s on the dry solid -phase-ex t raction

column, and, therefore, are reported in the

method with an estimated remark code. This

new method complements method 2001 by

using the sa me sa mple pr e p a r a tion a nd

anal y t i cal st eps but adds 41 new anal y t es.

RE FE RE NCE S CITE D

Am eri can S o ci et y for Test i n g and Mat e ri al s,

2000, Standard practice for estimation

of

holding time f o r

wa te r sa mple s

containing org a nic and inorg a nic

constituents: Annual book of ASTM

standards, Section 11, W a ter: W e st

Conshohocken, Penn., American

S o ci et y for Test i n g and Mat e ri al s,

v. 11.01, p. 485–490.

B a rbash, J

. E., and Resek, E.A., 1996,

Pesticides in g r ound water: Distribution,

trends, and g overning f a c t or s; Pe stic ide s

in the hy drolog ic sy stem: Chelsea,

Mich., Ann Arbor Press, v. 2, 588 p. Childress, C.J ., F o reman, W

. T., Connor, B

. F

., and Maloney

, T.J ., 1999, New reporting

procedures based on long -term method

detection levels and some considerations

f o r

inte r p r e ta tions of wa te r

- qua lity da ta

provided by the U.S. Geolog ical Survey

Na tiona l Wa te r Qua lity L a bor a t or y :

U.S. Geolog ical Survey Open-F ile

Report 99-133, 19 p.

Dennis, W

. H., Meier, E.P., Randall, W

. F

., Rosencrance, A.B ., and Rosenblatt,

D.H., 1979, Deg r adation of diaz inon by

sodium hy pochlorite . Che mistr y

a nd

a qua tic tox i c ity : Envir onme n ta l Sc ie nc e

& Technolog y

, v. 13, no. 5, p. 594–598.

F o reman, W

. T., Connor, B

. F ., B eaty

, D.A.,

Ke llog g

, E.K., Ma lone y

, T.J ., a nd Pr itt,

J

. W ., 2001, A long -term approach for

determining method de tection levels and

establishing reporting levels, in 2001

Pittsburg h Conference Abstract B ook,

New Orleans, L a ., March 4–9, 2001,

abstract no. 1374.

Gilliom, R.J ., B a r b a s h, J

. E., Kolpin, D.W.,

and L a rson, S.J ., 1999, Testing water

qua lity f

o r

pe stic ide pollution:

Environmental Science & Technolog y

, v. 33, no. 7, p. 164A.

Hoag lin, D.C., 1983, L e tter values: A set of

se le c t e d or de r sta tistic s, in Hoag lin,

D.C., Mosteller, F ., and Tukey

, J

. W

., eds., Understanding robust and

ex ploratory data analy s is: New York,

J ohn W iley and Sons, p. 33–54.

L a rson, S.J ., Capel, P.D., and Majewski,

M.S., 1997, Pesticides in surface water:

Distribution, trends, and g overning

factors; Pesticides in the hy drolog ic

sy stem: Chelsea, Mich., Ann Arbor

Press, v. 3, 373 p.

L a rson, S.J ., Gilliom, R.J ., and Capel, P.D.,

1998, Pesticides in streams of the United

Sta t e s —I nitia l r e sults f r o m the Na tiona l

Wa te r

- Q ua lity Asse ssme n t Pr og r a m: U.S.

Geol og i cal S u rvey W a t e r-R esources

I nvestig ations Report 98-4222, 99 p.

R e fer e nces C i ted 63

### L i ndley , C.E., Stewart, J

. T., and Sandstrom,

M.W ., 1996, Determination of low

concent r at i ons of acet ochl or i n wat e r by

a

u toma te d solid- pha se e x tr a c tion a nd

g a s c h r o ma tog r a phy with ma ss- se le c tive

detection: J ournal of Association of

Offi ci al Anal y t i cal C h em i s t s

I n ternational, v. 79, no. 4, p. 962–966.

Mackay , D., Shiu, W

. Y., and Ma, K.C., 1997,

Pe stic ide c h e mic a l s: I llustr a te d

handbook of phy sical-chemical

properties and envir onme n ta l f a te f o r

org a nic chemicals: B o ca Raton, L e wis

Publishers I n c, v. V, 812 p.

Majewski, M.J ., 1997, National and study unit

pesticide use: U.S. Geolog ical Survey

web site, accessed J u ly 31, 2000, at

http://wwwdcascr.wr.usg s .g ov/pnsp/natsu/

Miller, J

. C., and Mille r, J

. N., 1993, Statistics

for anal y t i cal chem i s t r y

(3d ed.): New

York, Ellis Horwood L imited, 233 p.

Sandstrom, M.W ., 1995, F iltration of waterse dime nt sa mple s f o r

the de te r mina tion

of org a nic compounds: U.S. Geolog ical

Survey W a ter-Resources I nvestig ations

Report 95-4105, 13 p.

U.S. Environmental Protection Ag ency , 1997,

Guidelines establishing test procedures

for the analy s is of pollutants (App. B

, Part 136, Definition and procedures for

the determination of the method

de te c tion limit) : U.S. Code of F e de r a l

Reg u lations, Title 40, p. 265–267.

_____2001, Pesticide tolera nce reassessment

and rereg i stration: USEPA web site,

accessed May 4, 2001, at URL

ht t p : / / www.e p a

. g o v / pe s t i c i d e s / r e r e g i s t r a t i on/



### U.S. Geolog ical Survey , 2000, Pesticides

analy z ed in NAW QA samples: Use,

c h e mic a l a n a l y s e s , a nd wa te r

- qua lity

criteria: web site accessed J u ly 31, 2000,

at http://ca.water.usg s .g ov /pnsp/anstrat/ 

### W e rner, S.L ., B u rkhardt, M.R., and

DeRusseau, S.N., 1996, Methods of

anal y s i s by t h e U.S

. Geol og i cal S u rvey

Na tiona l Wa te r Qua lity L a bor a t or y

—

De te r mina tion of pe stic ide s in wa te r by

Carbopak-B solid-pha se ex traction and

hi g h -perform ance l i qui d

chromatog r aphy : U.S. Geolog ical

Survey Open-F ile Report 96-216, 42 p.

W ilde, F

. D., Radtke, D.B ., Gibs, J acob, and

I w atsubo, R.T., eds., 1999, National

f i e l d ma nua l f o r

the c o lle c tion of wa te r

qua lity da ta : U.S. Ge olog ic a l Sur v e y Techniques of W a ter-Resources

I nvestig ations, book 9, chaps. A1

throug h A6.

Z a ug g

, S.D., Sandstrom, M.W ., Smith, S.G.,

and F e hlberg , K.M., 1995, Methods of

anal y s i s by t h e U.S

. Geol og i cal S u rvey

Na tiona l Wa te r Qua lity L a bor a t or y

—

De te r mina tion of pe stic ide s in wa te r by

C-18 solid-phase ex traction and

c a p illa r y

- c olumn g a s c h r o ma tog r a phy /

ma ss spe c t r o me tr y

with se le c t e d

- i on

monitoring : U.S. Geolog ical Survey

Open-F ile Report 95-181, 49 p.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 64

## Suppl ement A

— A u tomated Sol i d -Phase Extr acti on Pr ocedur e

### Z y mark AutoTrace Ex traction W o rkstation 1.20

AutoTrace Ex traction P r ocedure: 2001 CONDI TI ONI NG/EXTRACTI ON 9/8/94

Estimated time for samples: 57.8 minutes

Date: 8 Sep 94

Step 1: Process 6 samples us ing the following procedure:

S t ep 2: C ondition column with 3 mL of METHANOL into S O L V ENT W A S TE

Step 3: Condition column with 6 mL of W A TER into SOL V ENT W A STE

Step 4: L o ad 1,000 mL of sample onto column

Step 5: Dry column with g a s for 4 minutes

Step 6: Pause and alert operator, resume when C ONTI NUE is pressed

S t ep 7: C l ean each sam p l e pat h wi t h 50 m L cl eani n g sol u t i on

( i sopr opa nol: me thy l e n e c h lor i de : tolue n e ; 7:2:1) into SOL V ENT WASTE

S t ep 8: C l ean each sam p l e pat h wi t h 50 m L m e t h anol i n t o S O L V ENT W A S TE

Step 9: Clean each sample path with 100 mL distilled water into AQUEOUS W A STE

Step 10: Dry column with g a s for 0.1 minute

Step 11: END

Setup Parameters

[m L / m i n, m illiliters per m i nute; m L , m illiliter]

A u toT r ace 

### Ex traction W o rkstation

FLO W RA T ES

( m L/ mi n) SO LI D- PHA SE EXT RA CT I O N

PA RA M E T E RS

Condit i on fl ow: 25 Push de lay : 2 seconds

Load f l ow: 25 Air f a c t or : 0.5

Rinse flow : 25 Autowash v o lum e : 0.00 m L

Elut e f l ow: 5

Condit i on ai r pus h: 25 WORK ST AT I ON PARAMET E RS

Rinse ai r push : 25 Maxim u m elution v o lum e : 12.0 m L

Elut e ai r pu sh: 5 Exhaust fan on: Y Y=Yes N=No

Be e p e r on: N Y= Ye s N= No



### Na me Solve n ts

Solve n t 1 : Wa te r

Solve n t 2 : Me tha nol

Solve n t 3 : Solve n t 3

Solve n t 4 : Solve n t 4

Solve n t 5 : Solve n t 5

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 66

## Suppl ement B—I n str u cti ons for On-Si t e Pr ocessi ng

Using Solid-Phase Extraction (SPE)

### INS T RUCTIONS FOR ON-S ITE

PR OC ESSIN G U S IN G

SOLID

- PH A SE EXTR A C T ION ( SPE)

1. Gather the equipment and supplies needed

for on-site SPE listed in table 19.

2. R ecord t h e precl eaned S P E col u m n t y pe,

lot number, and weig ht on the field

form . P r epare t h e S P E col u m n by

conditioning with about 2 mL of

methanol, followed by about 2 mL of

water to remove ex cess methanol.

Allow the me tha nol a nd wa te r to f l ow

by g r avity throug h the column. AT NO

TI ME S HOUL D THE C O L U MN GO

DR Y ONC E C ONDI TI ONI NG HAS

STARTED (if it does, add methanol

then water to recondition ag ain).

Ma inta in the wa te r in the c o lumn be d

by replacing the water that drains

throug h, or by using an on-off valve to

stop all water from draining out of the

c o lumn.

3. Tare the weig ht of the amber g l ass 1-L

sa mple bottle . Colle c t , split, a nd f ilte r

samples using appropr iate procedures

(Sandstrom, 1995). Collect about 1 L

of

the sa mple in the 1- L sa mple bottle

( do not c o mple te ly f

ill the bottle ; le a v e

about a 2-cm headspace to add

conditioner and surrog a te).

4. W e ig h and record the amount of sample

collected. Add about

10 mL of the methanol by using the

bottle

- t op dispe n se r

. We ig h a nd r e c o r d

the sa mple

- p lus- me tha nol we ig ht.

5. Add the surrog a te solution (1.25 ng /μL )

contained in the 2-mL amber screw-cap

vi al (refer t o S p i k e Ki t I n st ruct i on

Ma nua l f o r

mor e de ta ile d inf o r

m a tion

on use of micropipet). Use the 100-μL

micropipet and a clean g l ass bore.

Withdr a w the solution into the g l a ss

bor e

, the n put the tip into the sa mple bottle , be low the sur f a c e of the sa mple

( tip the bottle on the side if ne e d e d to

reach bel o w t h e surface wi t h t h e t i p of

the micropipet), and press the plung er

to de live r the sur r o g a te to the sa mple

. Withdr a w the mic r opi pet, remove and

discard the g l ass bore, and rinse the

orang e -colored Teflon tip with

me tha nol. Swir l the sa mple to mix

. Detailed instructions on use of the

micropipet are contained in the spike

kit.

6. Obt a i n a pl ast i c 1-L beaker for col l ect i n g

t h e ex t r act ed wat e r.

7. I f necessary , adjust the pump flow rate to

20 to 25 mL /min by using the c l e a n ing

solutions and g r aduated cy linder or

beaker t o m easure vol um e.

8. I n sert the inlet end of the Teflon-PF A

tubing from the SPE pump into the

sa mple bottle . Tur n on the pump a nd

al l o w t h e ai r t o be di spl aced from t h e

Teflon tubing , then attach the L u er tip

of

the SPE c o lumn to the outle t e nd of

the pump tubing . I nvert the column to

discard any conditioning water

r e ma ining in the SPE r e se r voir a nd

beg i n col l ect i n g ex t r act ed wat e r t h at

pa sse s thr oug h the c o lumn into the

plastic beaker. Pump sample throug h

the c o lumn a t 20 to 25 mL /min. Af te r

sample has been pumped throug h

column, turn off pump, disconnect SPE

column, and record final weig ht of

sample processed throug h the column.

9. Re move e x c e ss wa te r f

r o m SPE c o lumn

by using a sy ring e to blow out water.

Wr ite sa mple I D on si de of column, and

store in 40-mL g l ass ampule. Store

col u m n s i n cool pl ace (bet ween 4–

25 o 

### C)

.

D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 68

### CLE A NING P R OCE DURE

Clean all equipment after use by rinsing

with a laboratory deterg ent (L iquinox solution,

0.2 percent), followed by rinses with about 30

mL of ta p wa te r to r e move the de te r g e n t;

finally , rinse with about 30 mL of methanol.

W r ap all opening s of cleaned material with

aluminum foil.

Sa mple s ( a nd a n y ma te r i a l s a dde d to

samples) should contact only g l ass, Teflon,

ceram i c or st ai nl ess st eel (or other metal).

QU A L ITY

- A SSU R A N C E SA M P LES

F i eld equipment blank: Process a

sa mple of pe stic ide

- g r a d e wa te r ( a va ila ble

from NW QL , throug h One Stop Shopping ) 1



### e x a c tly a s the sa mple s. This inc l ude s

sa mple bottle s, c o mpositing

, splitting

, a nd

f iltr a tion e quipme n t a s we ll a s the SPE sy stem. Process the field-equipment blank

at the start of sampling

, and then after about

every 10 to 15 samples. More frequent

blanks are alway s helpful.

F i e l d ma tr ix spike s : Colle c t duplic a t e

samples and add the 2.0-ng /μL

- spike

solution to one sample. Use the 100-μL

micropipet to add the spike solution, which

is contained in a 2-mL g l ass vial, after about

e v e r y

20 sa mple s. Add the sur r o g a te to

every spi k ed sam p l e

.

FURTHE R INFORMA T ION

C ont act Frank W i ebe (e-m ai l

– fwwiebe@usg s .g ov; 303-236-3279), or

Mark Sandstrom (e-mail – sandstro@usg s .g ov;

303-236-3943) for additional information.

T a b l e 19. Equipm ent and s upplies r equir ed f o r br oad s pec tr um pes tic i de analy s is

( m ethods 2010 and 2011) by on- s i te s o lid- phas e ex tr ac tion

[m m

, m illim eter; in ., in ch ; m L , m illiliter; SP E, so lid

- p h a se ex tractio n ; μL , m i cro liter; g

, g r am ;

μm , m i cro m eter; m g , m illig ram ; L

, liter; n g / μL , n a n o g r am p e r m i cro liter]

Number per

samp l e

Equipm ent

Filter Un it, 147- m m

diam eter, alu m in u m , an d FMI Model QB

- 1 C K C pu m p an d 1/4- in

. diam eter con v o lu ted T e f l on tu bin g 1

T e f l on s q u eeze bottle, 250 m L , f o r m e th an ol 1

V a l v el es s

, pi s t on

- t y p e m e t e ri n g pu m p f o r S P E; F M I Model R H B 0C K C 1

F i x e d v o l u m e (100- μL ) m i cropi pet 1

Port abl e bal a n ce (1,200.0 g ) 1

Filters , 147- m m

diam eter, 0.7- μm pore diam eter, preclean ed 1–5

B o ttle- t op dis p en s e r, 1–5 m L , f o r m e th an ol (option a l) 1

T e f l on s q u eeze bottle, 250 m L , f o r pes ticide- g r ade w a ter 1

Supplies

S P E col u m n s

, In t e rn at i o n a l S o rben t T ech n o l o g i es Is ol u t e C

- 18, 500 m g , precl ean ed 1 1

Sam p le b o ttles, 1

- L

, am b e r 1

D i s pos abl e g l as s bores , f o r 100- μL m i cropi pet 1 1

Sur r o ga t e m i xt ur e

, 1

. 2 5 ng/ μ L

, 2

- m L vi a l 1 1

L i qu i n ox det e rg en t

, 0.2- percen t s o l u t i o n

, 200 m L 1

Pes t i c i d e- g r ade m e t h an ol , 200 m L 1

P e sticid e- g r ad e w a ter, 5 m L 1

A l u m in u m f

o il, ro ll 1

G l ov es , di s pos abl e , n o n pow dered, m e di u m 1–5

Sp ik e k it, in clu d in g In stru ctio n Man u a l 1 1

S p i k e m i x t u r e, 1–10 n g / μL , 2- m L v i al 1 1

1 Sup p l i e s o b t a i ne d t h r o ugh W R D O n e St o p Sh oppin g <h ttp://1s t op.u s g s .g ov >.

Supplement B 69D e ter m ination of Moder a te-U se Pesticides and Selected D e gr adates in Water

by

C

- 18 Solid-Phase Extr action and G as C h r o matogr aphy /Mass Spectr o metr y 70 

## Solid-Phase Extraction, GC/M S Analysis, Filtered Water

M e thods 2010 and 2011

Statio n ID o r Un iq u e Nu m b e r : Statio n Nam e

D a t e : Ti m e Co llecto r :

T e l e ph on e N u m b er of C o l l ect or:

C o mme n t s :

ON-SITE INFORM ATION

Filter Sa m p le ( 0

. 7

- μm g l ass f i b e r f ilter) Date f iltered :

P r io r to f iltratio n

, reco rd b o ttle tare w t

. g

SP E Co lum n Bran d or T y pe:

Lo t # :

Dry W t .: g

SP E Co lum n Co ndit i o n ing : D a t e of S P E procedu r e:

Meth an ol (2 m L ): m L

P e sticid e- g r ad e w a ter (2 m L ): m L

(DO NOT L E T COL U MN GO DRY ONCE CONDIT I ONING ST A R T E D)

Sa m p le Sam p le + b o ttle w t .: g

(- ) b o ttle tare w t .: g

= Sam p le w t .: g

A d d m e th an o l co n d itio n e r (1 % sam p le w t .): m L

Sam p le + b o ttle + m e th an o l : g

S u rrogate So lu tio n ID:

V o l u m e added: μL

QA Sa m p les - Spik e M i xt ure

So lu tio n ID:

V o l u m e added (100 μL ): μL

Sa m p le t h ro ug h co lum n :

Sam p le + plas tic beak er: g

plas tic beak er: g

Flow rate: (=sam p le w t . ex tracted /tim e) m L /m in

Start tim e: h r :m in

Fin i sh tim e: h r :m in

Rem o v e ex cess w a ter — W r ite statio n IP D, d a te, tim e o n co lu m n

— Sto r e in 4 0

- m L v i al @ 4 ° C

NWQ L INFORM ATION

La b I D : Set #: Date R eceiv e d

Dry co lum n w i th N 2 or C O 2 : D a t e :

P r e ssur e : lb /in 2

Ti m e : m i n

Dry SP E cartrid g e w t .: g

SP E Elut io n D a t e :

A d d 1

. 8 m L elu tio n so lv en t (3 :1 ) m L

Int erna l St a nda rd ( P AH

- d n m i x t ure in toluene k eeper)

So lu tio n ID:

V o l u m e added (100 μL ): μL

E vap orate s o l v en t - n i trogen D a t e :

P r e ssur e : lb /in 2

Ti m e : m i n

A n al ys i s - In s t ru m e n t ID: D a t e :

C o mme n t s :