200.10-1

Method 200.10

Determination of Trace Elements in Marine Waters by

On-Line Chelation Preconcentration and Inductively

Coupled Plasma - Mass Spectrometry

Stephen E. Long

Technology Applications, Inc.

and

Theodore D. Martin

Chemical Exposure Research Branch

Human Exposure Research Division

Revision 1.6

September 1997

Edited by

John T. Creed

National Exposure Research Laboratory

Office of Research and Development

U.S. Environmental Protection Agency

Cincinnati, Ohio 45268
Revision 1.6 September 1997 200.10-2

Method 200.10

Determination of Trace Elements in Marine Waters by On-Line Chelation

Preconcentration and Inductively Coupled Plasma - Mass Spectrometry

1.0 Scope and Application

1.1 This method describes procedures for

preconcentration and determination of total recoverable

trace elements in marine waters, including estuarine

water, seawater, and brines.

1.2 Acid solubilization is required prior to the

determination of total recoverable elements to facilitate

breakdown of complexes or colloids that might influence

trace element recoveries. This method should only be

used for preconcentration and determination of trace

elements in aqueous samples.

1.3 This method is applicable to the following

elements:

Chemical Abstracts Service

Element Registry Numbers (CASRN)

Cadmium (Cd) 7440-43-9

Cobalt (Co) 7440-48-4

Copper (Cu) 7440-50-8

Lead (Pb) 7439-92-1

Nickel (Ni) 7440-02-0

Uranium (U) 7440-61-1

Vanadium (V) 7440-62-2

1.4 Method detection limits (MDLs) for these elements will be dependent on the specific instrumentation

employed and the selected operating conditions. However, the MDLs should be essentially independent of the

matrix because elimination of the matrix is a feature of

the method. Reagent water MDLs, which were determined using the procedure described in Section 9.2.4,

are listed in Table 1.

1.5 A minimum of 6-months experience in the use of

commercial instrumentation for inductively coupled

plasma mass spectrometry (ICP-MS) is recommended.

2.0 Summary of Method

2.1 This method is used to preconcentrate trace

elements using an iminodiacetate functionalized chelating

resin. Following acid solubilization, the sample is

1,2

buffered prior to the chelating column using an on-line

system. Groups I and II metals, as well as most anions,

are selectively separated from the analytes by elution with

ammonium acetate at pH 5.5. The analytes are

subsequently eluted into a simplified matrix consisting of

dilute nitric acid and are determined by ICP-MS using a

directly coupled on-line configuration.

2.2 The determinative step in this method is ICPMS. Sample material in solution is introduced by

3-5

pneumatic nebulization into a radio frequency plasma

where energy transfer processes cause desolvation,

atomization and ionization. The ions are extracted from

the plasma through a differentially pumped vacuum

interface and separated on the basis of their mass-tocharge ratio by a quadrupole mass spectrometer having

a minimum resolution capability of 1 amu peak width at

5% peak height. The ions transmitted through the

quadrupole are registered by a continuous dynode electron multiplier or Faraday detector and the ion information

is processed by a data handling system. Interferences

relating to the technique (Section 4) must be recognized

and corrected. Such corrections must include

compensation for isobaric elemental interferences and

interferences from polyatomic ions derived from the

plasma gas, reagents or sample matrix. Instrumental drift

must be corrected for by the use of internal standardization.

3.0 Definitions

3.1 Calibration Blank (CB) -- A volume of reagent

water fortified with the same matrix as the calibration

standards but without the analytes, internal standards, or

surrogate analytes.

3.2 Calibration Standard (CAL) -- A solution prepared from the primary dilution standard solution or stock

standard solutions and the internal standards and surrogate analytes. The CAL solutions are used to calibrate the

instrument response with respect to analyte concentration.

3.3 Instrument Detection Limit (IDL) -- The minimum quantity of analyte or the concentration equivalent

that gives an analyte signal equal to three times the

standard deviation of the background signal at the selected wavelength, mass, retention time, absorbance line,

etc.

3.4 Instrument Performance Check Solution (IPC)

-- A solution of one or more method analytes, surrogates,

internal standards, or other test substances used to

evaluate the performance of the instrument system with

respect to a defined set of criteria.

3.5 Internal Standard (IS) -- A pure analyte(s) added

to a sample, extract, or standard solution in known

amount(s) and used to measure the relative responses
200.10-3 Revision 1.6 September 1997

of other method analytes and surrogates that are compo- materials or purchased from a reputable commercial

nents of the same sample or solution. The internal source.

standard must be an analyte that is not a sample component. 3.14 Total Recoverable Analyte (TRA) -- The

3.6 Laboratory Fortified Blank (LFB) -- An aliquot sample or an unfiltered aqueous sample following

of reagent water or other blank matrices to which known treatment by refluxing with hot dilute mineral acid(s) as

quantities of the method analytes are added in the specified in the method.

laboratory. The LFB is analyzed exactly like a sample,

and its purpose is to determine whether the methodology 3.15 Tuning Solution (TS) -- A solution that is used to

is in control and whether the laboratory is capable of adjust instrument performance prior to calibration and

making accurate and precise measurements. sample analyses.

3.7 Laboratory Fortified Sample Matrix (LFM) -- An

aliquot of an environmental sample to which known

quantities of the method analytes are added in the

laboratory. The LFM is analyzed exactly like a sample,

and its purpose is to determine whether the sample matrix

contributes bias to the analytical results. The background

concentrations of the analytes in the sample matrix must

be determined in a separate aliquot and the measured

values in the LFM corrected for background

concentrations.

3.8 Laboratory Reagent Blank (LRB) -- An aliquot

of reagent water or other blank matrices that are treated

exactly as a sample including exposure to all glassware,

equipment, solvents, reagents, internal standards, and

surrogates that are used with other samples. The LRB is

used to determine if method analytes or other interferences are present in the laboratory environment, the

reagents, or the apparatus.

3.9 Linear Dynamic Range (LDR) -- The absolute

quantity or concentration range over which the instrument

response to an analyte is linear.

3.10 Material Safety Data Sheet (MSDS) -- Written

information provided by vendors concerning a chemical’s

toxicity, health hazards, physical properties, fire, and

reactivity data including storage, spill, and handling

precautions.

3.11 Method Detection Limit (MDL) -- The minimum

concentration of an analyte that can be identified,

measured, and reported with 99% confidence that the

analyte concentration is greater than zero.

3.12 Quality Control Sample (QCS) -- A solution of

method analytes of known concentrations that is used to

fortify an aliquot of LRB or sample matrix. The QCS is

obtained from a source external to the laboratory and

different from the source of calibration standards. It is

used to check laboratory performance with externally

prepared test materials.

3.13 Stock Standard Solution (SSS) -- A concentrated solution containing one or more method analytes

prepared in the laboratory using assayed reference 

concentration of analyte determined to be in either a solid

4.0 Interferences

4.1 Several interference sources may cause inaccuracies in the determination of trace elements by ICP-MS.

These are:

4.1.1 Isobaric elemental interferences -- Are caused

by isotopes of different elements that form singly or

doubly charged ions of the same nominal mass-tocharge ratio and that cannot be resolved by the mass

spectrometer in use. All elements determined by this

method have, at a minimum, one isotope free of isobaric

elemental interference. The analytical isotopes recommended for use with this method are listed in Table 1.

4.1.2 Abundance sensitivity -- Is a property defining

the degree to which the wings of a mass peak contribute

to adjacent masses. The abundance sensitivity is affected by ion energy and quadrupole operating pressure.

Wing overlap interferences may result when a small ion

peak is being measured adjacent to a large one. The

potential for these interferences should be recognized

and the spectrometer resolution adjusted to minimize

them.

4.1.3 Isobaric polyatomic ion interferences -- Are

caused by ions consisting of more than one atom that

have the same nominal mass-to-charge ratio as the

isotope of interest and that cannot be resolved by the

mass spectrometer in use. These ions are commonly

formed in the plasma or interface system from support

gases or sample components. Such interferences must

be recognized, and when they cannot be avoided by the

selection of alternative analytical isotopes, appropriate

corrections must be made to the data. Equations for the

correction of data should be established at the time of the

analytical run sequence as the polyatomic ion

interferences will be highly dependent on the sample

matrix and chosen instrument conditions.

4.1.4 Physical interferences -- Are associated with the

physical processes that govern the transport of sample

into the plasma, sample conversion processes in the

plasma, and the transmission of ions through the plasma

mass spectrometer interface. These interferences may

result in differences between instrument responses for
Revision 1.6 September 1997 200.10-4

the sample and the calibration standards. Physical as cyanides or sulfides. Acidification of samples should be

interferences may occur in the transfer of solution to the performed in a fume hood.

nebulizer (e.g., viscosity effects), at the point of aerosol

formation and transport to the plasma (e.g., surface 5.4 All personnel handling environmental samples

tension), or during excitation and ionization processes known to contain or to have been in contact with human

within the plasma itself. Internal standardization may be waste should be immunized against known disease

effectively used to compensate for many physical causative agents.

interference effects. Internal standards ideally should

6

have similar analytical behavior to the elements being 5.5 It is the responsibility of the user of this method to

determined. comply with relevant disposal and waste regulations. For

4.1.5 Memory interferences -- Result when isotopes of

elements in a previous sample contribute to the signals

measured in a new sample. Memory effects can result

from sample deposition on the sampler and skimmer

cones and from the buildup of sample material in the

plasma torch and spray chamber. The site where these

effects occur is dependent on the element and can be

minimized by flushing the system with a rinse blank

between samples. Memory interferences from the chelating system may be encountered especially after

analyzing a sample containing high concentrations of the

analytes. A thorough column rinsing sequence following

elution of the analytes is necessary to minimize such

interferences.

4.2 A principal advantage of this method is the

selective elimination of species giving rise to polyatomic

spectral interferences on certain transition metals (e.g.,

removal of the chloride interference on vanadium). As

the majority of the sample matrix is removed, matrix

induced physical interferences are also substantially

reduced.

4.3 Low recoveries may be encountered in the

preconcentration cycle if the trace elements are

complexed by competing chelators in the sample or are

present as colloidal material. Acid solubilization pretreatment is employed to improve analyte recovery and to

minimize adsorption, hydrolysis, and precipitation effects.

5.0 Safety

5.1 Each chemical reagent used in this method

should be regarded as a potential health hazard and

exposure to these reagents should be as low as reasonably achievable. Each laboratory is responsible for

maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals

specified in this method. A reference file of material

7,8

data handling sheets should also be available to all

personnel involved in the chemical analysis.

5.2 Analytical plasma sources emit radio frequency

radiation in addition to intense UV radiation. Suitable

precautions should be taken to protect personnel from

such hazards.

5.3 The acidification of samples containing reactive

materials may result in the release of toxic gases, such

guidance see Sections 14.0 and 15.0.

6.0 Equipment and Supplies

6.1 Preconcentration System -- System containing

no metal parts in the analyte flow path, configured as

shown in Figure 1.

6.1.1 Column -- Macroporous iminodiacetate chelating

resin (Dionex Metpac CC-1 or equivalent).

6.1.2 Sample loop -- 10-mL loop constructed from

narrow bore, high-pressure inert tubing, Tefzel ethylene

tetra-fluoroethylene (ETFE) or equivalent.

6.1.3 Eluent pumping system (Pl) -- Programmable

flow, high pressure pumping system, capable of

delivering either one of two eluents at a pressure up to

2000 psi and a flow rate of 1-5 mL/min.

6.1.4 Auxiliary pumps -- On line buffer pump (P2),

piston pump (Dionex QIC pump or equivalent) for

delivering 2M ammonium acetate buffer solution; carrier

pump (P3), peristaltic pump (Gilson Minipuls or equivalent) for delivering 1% nitric acid carrier solution; sample

pump (P4), peristaltic pump for loading sample loop.

6.1.5 Control valves -- Inert double stack, pneumatically operated four-way slider valves with connectors.

6.1.5.1 Argon gas supply regulated at 80-100 psi.

6.1.6 Solution reservoirs -- Inert containers, e.g., high

density polyethylene (HDPE), for holding eluent and

carrier reagents.

6.1.7 Tubing -- High pressure, narrow bore, inert

tubing (e.g., Tefzel ETFE or equivalent) for interconnection of pumps/valve assemblies and a minimum length

for connection of the preconcentration system to the ICPMS instrument.

6.2 Inductively Coupled Plasma - Mass Spectrometer

6.2.1 Instrument capable of scanning the mass range

5-250 amu with a minimum resolution capability of 1 amu

peak width at 5% peak height. Instrument may be fitted

with a conventional or extended dynamic range detection

system.
200.10-5 Revision 1.6 September 1997

6.2.2 Argon gas supply (high-purity grade, 99.99%). 6.4.4 Centrifuge -- Steel cabinet with guard bowl,

6.2.3 A mass-flow controller on the nebulizer gas

supply is recommended. A water-cooled spray chamber

may be of benefit in reducing some types of interferences (e.g., polyatomic oxide species).

6.2.4 Operating conditions -- Because of the diversity electrode system with a resolution of ± 0.1 pH units.

of instrument hardware, no detailed instrument operating

conditions are provided. The analyst is advised to follow

the recommended operating conditions provided by the

manufacturer.

6.2.5 If an electron multiplier detector is being used,

precautions should be taken, where necessary, to

prevent exposure to high ion flux. Otherwise changes in

instrument response or damage to the multiplier may

result. Samples having high concentrations of elements

beyond the linear range of the instrument and with

isotopes falling within scanning windows should be di--

luted prior to analysis.

6.3 Labware -- For the determination of trace

elements, contamination and loss are of critical concern.

Potential contamination sources include improperly

cleaned laboratory apparatus and general contamination

within the laboratory environment. A clean laboratory

work area, designated for trace element sample handling, must be used. Sample containers can introduce

positive and negative errors in the determination of trace

elements by (1) contributing contaminants through

surface desorption or leaching or (2) depleting element

concentrations through adsorption processes. For these

reasons, borosilicate glass is not recommended for use

with this method. All labware in contact with the sample

should be cleaned prior to use. Labware may be soaked

overnight and thoroughly washed with laboratory-grade

detergent and water, rinsed with water, and soaked for 4

hr in a mixture of dilute nitric and hydrochloric acids,

followed by rinsing with ASTM type I water and oven

drying.

6.3.1 Griffin beakers, 250-mL, polytetrafluoroethylene

(PTFE) or quartz.

6.3.2 Storage bottles -- Narrow mouth bottles, Teflon

FEP (fluorinated ethylene propylene), or HDPE, 125-mL

and 250-mL capacities.

6.4 Sample Processing Equipment

6.4.1 Air displacement pipetter -- Digital pipet system

capable of delivering volumes from 10 to 2500 FL with an

assortment of metal-free, disposable pipet tips.

6.4.2 Balances -- Analytical balance, capable of

accurately weighing to ±0.1 mg; top pan balance, accurate to ± 0.01g.

6.4.3 Hot plate -- Corning PC100 or equivalent.

electric timer and brake.

6.4.5 Drying oven -- Gravity convection oven with

thermostatic control capable of maintaining 105EC±5EC.

6.4.6 pH meter -- Bench mounted or hand-held

7.0 Reagents and Standards

7.1 Water -- For all sample preparation and dilutions, ASTM type I water (ASTM D1193) is required.

7.2 Reagents may contain elemental impurities that

might affect the integrity of analytical data. Because of

the high sensitivity of this method, ultra high-purity

reagents must be used unless otherwise specified. To

minimize contamination, reagents should be prepared

directly in their designated containers where possible.

7.2.1 Acetic acid, glacial (sp. gr. 1.05).

7.2.2 Ammonium hydroxide (20%).

7.2.3 Ammonium acetate buffer 1M, pH 5.5 -- Add 58-

mL (60.5 g) of glacial acetic acid to 600-mL of ASTM

type water. Add 65 mL (60 g) of 20% ammonium hydroxide and mix. Check the pH of the resulting solution by

withdrawing a small aliquot and testing with a calibrated

pH meter, adjusting the solution to pH 5.5±0.1 with small

volumes of acetic acid or ammonium hydroxide as necessary. Cool and dilute to 1 L with ASTM type I water.

7.2.4 Ammonium acetate buffer 2M, pH 5.5 -- Prepare

as for Section 7.2.3 using 116 mL (121g) glacial acetic

acid and 130 mL (120 g) 20% ammonium hydroxide,

diluted to 1000 mL with ASTM type I water.

Note: The ammonium acetate buffer solutions may be

further purified by passing them through the

chelating column at a flow rate of 5.0-mL/min.

With reference to Figure 1, pump the buffer

solution through the column using pump P1, with

valves A and B off and valve C on. Collect the

purified solution in a container at the waste

outlet. Following this, elute the collected contaminants from the column using 1.25M nitric acid for

5 min at a flow rate of 4.0 mL/min.

7.2.5 Nitric acid, concentrated (sp.gr. 1.41).

7.2.5.1 Nitric acid 1.25M -- Dilute 79 mL (112 g) conc.

nitric acid to 1000-mL with ASTM type I water.

7.2.5.2 Nitric acid 1% -- Dilute 10 mL conc. nitric acid to

1000 mL with ASTM type I water.
Revision 1.6 September 1997 200.10-6

7.2.5.3 Nitric acid (1+1) -- Dilute 500 mL conc. nitric acid heating to effect solution. Cool and dilute to 100 mL with

to 1000-mL with ASTM type I water. ASTM type I water.

7.2.5.4 Nitric acid (1+9) -- Dilute 100 mL conc. nitric acid 7.3.7 Scandium solution, stock 1 mL = 1000 Fg Sc:

to 1000-mL with ASTM type I water.

7.2.6 Oxalic acid dihydrate (CASRN 6153-56-6), 0.2M

-- Dissolve 25.2 g reagent grade C2H2O4·2H2O in 250-mL

ASTM type I water and dilute to 1000 mL with ASTM type 7.3.8 Terbium solution, stock 1 mL = 1000 Fg Tb:

I water. Caution - Oxalic acid is toxic; handle with care.

7.3 Standard Stock Solutions -- May be purchased

from a reputable commercial source or prepared from

ultra high-purity grade chemicals or metals (99.99-

99.999% pure). All salts should be dried for 1 h at 105EC,

unless otherwise specified. (Caution- Many metal salts

are extremely toxic if inhaled or swallowed. Wash hands

thoroughly after handling.) Stock solutions should be

stored in plastic bottles. The following procedures may

be used for preparing standard stock solutions:

Note: Some metals, particularly those that form surface oxides require cleaning prior to being

weighed. This may be achieved by pickling the

surface of the metal in acid. An amount in excess of the desired weight should be pickled

repeatedly, rinsed with water, dried, and

weighed until the desired weight is achieved.

7.3.1 Cadmium solution, stock 1 mL = 1000 Fg Cd:

Pickle cadmium metal in (1+9) nitric acid to an exact

weight of 0.100 g. Dissolve in 5-mL (1+1) nitric acid,

heating to effect solution. Cool and dilute to 100-mL with

ASTM type I water.

7.3.2 Cobalt solution, stock 1 mL = 1000 Fg Co:

Pickle cobalt metal in (1+9) nitric acid to an exact weight

of 0.100 g. Dissolve in 5 mL (1+1) nitric acid, heating to

effect solution. Cool and dilute to 100 mL with ASTM type

I water.

7.3.3 Copper solution, stock 1 mL = 1000 Fg Cu:

Pickle copper metal in (1+9) nitric acid to an exact weight

0.100 g. Dissolve in 5 mL (1+1) nitric acid, heating to

effect solution. Cool and dilute to 100 mL with ASTM type

I water.

7.3.4 lndium solution, stock 1 mL = 1000 Fg In: Pickle

indium metal in (1+1) nitric acid to an exact weight 0.100

g. Dissolve in 10 mL (1+1) nitric acid, heating to effect

solution. Cool and dilute to 100 mL with ASTM type I

water.

7.3.5 Lead solution, stock 1 mL = 1000 Fg Pb: Dissolve 0.1599 g PbNO in 5 mL (1+1) nitric acid. Dilute to 7.5 Blanks -- Four types of blanks are required for 3

100 mL with ASTM type I water. this method. A calibration blank is used to establish the

7.3.6 Nickel solution, stock 1 mL = 1000 Fg Ni: blank is used to assess possible contamination from the

Dissolve 0.100 g nickel powder in 5 mL conc. nitric acid,

Dissolve 0.1534 g Sc O in 5 mL (1+1) nitric acid, 2 3

heating to effect solution. Cool and dilute to 100 mL with

ASTM type I water.

Dissolve 0.1176 g Tb4O7 in 5 mL conc. nitric acid, heating

to effect solution. Cool and dilute to 100 mL with ASTM

type I water.

7.3.9 Uranium solution, stock 1 mL = 1000 Fg U:

Dissolve 0.2110 g UO2(NO3)2·6H2O (Do Not Dry) in 20

mL ASTM type I water. Add 2-mL (1+1) nitric acid and

dilute to 100-mL with ASTM type I water.

7.3.10 Vanadium solution, stock 1 mL = 1000 Fg V:

Pickle vanadium metal in (1+9) nitric acid to an exact

weight of 0.100 g. Dissolve in 5-mL (1+1) nitric acid,

heating to effect solution. Cool and dilute to 100 mL with

ASTM type I water.

7.3.11 Yttrium solution, stock 1 mL = 1000 Fg Y:

Dissolve 0.1270 g Y2O3 in 5 mL (1+1) nitric acid, heating

to effect solution. Cool and dilute to 100 mL with ASTM

type I water.

7.4 Multielement Stock Standard Solution -- Care

must be taken in the preparation of multielement stock

standards that the elements are compatible and stable.

Originating element stocks should be checked for

impurities that might influence the accuracy of the

standard. Freshly prepared standards should be transferred to acid cleaned, new FEP or HDPE bottles for

storage and monitored periodically for stability. A

multielement stock standard solution containing the

elements, cadmium, cobalt, copper, lead, nickel, uranium, and vanadium (1 mL = 10 Fg) may be prepared by

diluting 1 mL of each single element stock in the list to

100 mL with ASTM type I water containing 1% (v/v) nitric

acid.

7.4.1 Preparation of calibration standards -- Fresh

multielement calibration standards should be prepared

weekly. Dilute the stock multielement standard solution

in 1% (v/v) nitric acid to levels appropriate to the required

operating range. The element concentrations in the

standards should be sufficiently high to produce good

measurement precision and to accurately define the

slope of the response curve. A suggested mid-range

concentration is 10 Fg /L.

analytical calibration curve, and the laboratory reagent

sample preparation procedure. The laboratory fortified

blank is used to assess the recovery of the method
200.10-7 Revision 1.6 September 1997

analytes and the rinse blank is used between samples to standard using the direct addition method (Meminimize memory from the nebulizer/spray chamber thod A, Section 10.5) as it is not efficiently

surfaces. concentrated on the iminodiacetate column.

7.5.1 Calibration blank -- Consists of 1% (v/v) nitric acid

in ASTM type I water (Section 7.2.5.2).

7.5.2 Laboratory reagent blank (LRB) -- Must contain

all the reagents in the same volumes as used in processing the samples. The LRB must be carried through the

entire sample digestion and preparation scheme.

7.5.3 Laboratory Fortified Blank (LFB) -- To an aliquot

of LRB, add aliquots from the multielement stock standard (Section 7.4) to produce a final concentration of 10

Fg/L for each analyte. The fortified blank must be carried

through the entire sample pretreatment and analytical

scheme.

7.5.4 Rinse Blank (RB) -- Is a 1% (v/v) nitric acid

solution that is delivered to the lCP-MS between samples

(Section 7.2.5.2).

7.6 Tuning Solution -- This solution is used for

instrument tuning and mass calibration prior to analysis

(Section 10.2). The solution is prepared by mixing nickel,

yttrium, indium, terbium, and lead stock solutions (Section 7.3) in 1% (v/v) nitric acid to produce a concentration

of 100 Fg/L of each element.

7.7 Quality Control Sample (QCS) -- A quality

control sample having certified concentrations of the

analytes of interest should be obtained from a source

outside the laboratory. Dilute the QCS if necessary with

1% nitric acid, such that the analyte concentrations fall

within the proposed instrument calibration range.

7.8 Instrument Performance Check (IPC) Solution

-- The IPC solution is used to periodically verify instrument performance during analysis. It should be prepared

by combining method analytes at appropriate concentrations to approximate the midpoint of the calibration curve.

The IPC solution should be prepared from the same

standard stock solutions used to prepare the calibration

standards and stored in a FEP bottle. Agency programs

may specify or request that additional instrument performance check solutions be prepared at specified concentrations in order to meet particular program needs.

7.9 Internal Standards Stock Solution, 1 mL =

100 Fg -- Dilute 10-mL of scandium, yttrium, indium,

terbium, and bismuth stock standards (Section 7.3) to

100-mL with ASTM type I water, and store in a Teflon

bottle. Use this solution concentrate for addition to

blanks, calibration standards and samples (Method A,

Section 10.5), or dilute by an appropriate amount using

1% (v/v) nitric acid, if the internal standards are being

added by peristaltic pump (Method B, Section 10.5).

Note: Bismuth should not be used as an internal

8.0 Sample Collection, Preservation, and

Storage

8.1 Prior to the collection of an aqueous sample,

consideration should be given to the type of data required, so that appropriate preservation and pretreatment

steps can be taken. Acid preservation should be performed at the time of sample collection or as soon

thereafter as practically possible. The pH of all aqueous

samples must be tested immediately prior to aliquoting

for analysis to ensure the sample has been properly

preserved. If properly acid preserved, the sample can be

held up to 6 months before analysis.

8.2 For the determination of total recoverable

elements in aqueous samples, acidify with (1+1) nitric

acid (high purity) at the time of collection to pH<2;

normally, 3 mL of (1+1) acid per liter of sample is

sufficient for most samples. The sample should not be

filtered prior to analysis.

Note: Samples that cannot be acid preserved at the

time of collection because of sampling limitations or transport restrictions, or are >pH2

because of high alkalinity should be acidified

with nitric acid to pH<2 upon receipt in the

laboratory. Following acidification, the sample

should be held for 16 h and the pH verified to be

<2 before withdrawing an aliquot for sample

processing.

8.3 For aqueous samples, a field blank should be

prepared and analyzed as required by the data user. Use

the same container and acid as used in sample collection.

9.0 Quality Control

9.1 Each laboratory using this method is required to

operate a formal quality control (QC) program. The

minimum requirements of this program consist of an

initial demonstration of laboratory capability and the

periodic analysis of laboratory reagent blanks, fortified

blanks and other laboratory solutions as a continuing

check on performance. The laboratory is required to

maintain performance records that define the quality of

the data generated.

9.2 Initial Demonstration of Performance (Mandatory)

9.2.1 The initial demonstration of performance is used

to characterize instrument performance (determination of
Revision 1.6 September 1997 200.10-8

linear dynamic ranges and analysis of quality control single laboratory MDL values using this method

samples) and laboratory performance (determination of are given in Table 1.

method detection limits) prior to samples being analyzed

by this method. MDLs should be determined every six months, when a

9.2.2 Linear calibration ranges -- The upper limit of the cant change in the background or instrument response.

linear calibration range should be established for each

analyte. Linear calibration ranges should be determined

every six months or whenever a significant change in

instrument response is expected.

9.2.3 Quality control sample (QCS) -- When beginning must analyze at least one LRB (Section 7.5.2) with each

the use of this method, on a quarterly basis or as required to meet data-quality needs, verify the calibration

standards and acceptable instrument performance with

the preparation and analyses of a QCS (Section 7.7). If

the determined concentrations are not within ± 10% of

the stated values, performance of the determinative step

of the method is unacceptable. The source of the problem must be identified and corrected before either

proceeding with the initial determination of method

detection limits or continuing with ongoing analyses. must analyze at least one LFB (Section 7.5.3) with each

9.2.4 Method detection limit (MDL) -- MDLs must be ery (Section 9.4.3). If the recovery of any analyte falls

established for all analytes, using reagent water (blank)

fortified at a concentration of two to three times the

estimated instrument detection limit. To determine MDL 9

values, take seven replicate aliquots of the fortified

reagent water and process through the entire analytical

method. Perform all calculations defined in the method

and report the concentration values in the appropriate assess laboratory performance against the required conunits. Calculate the MDL as follows: trol limits of 85-115% (Section 9.3.2). When sufficient

MDL = (t) x (S) minimum of 20-30 analyses), optional control limits can

where: t = Student's t value for a 99% confidence level the standard deviation (S) of the mean recovery. These

and a standard deviation estimate with n-1 data can be used to establish the upper and lower control

degrees of freedom [t = 3.14 for seven limits as follows:

replicates].

S = standard deviation of the replicate analyses.

Note: If the relative standard deviation (RSD) from the

analyses of the seven aliquots is <15%, the The optional control limits must be equal to or better than

concentration used to determine the analyte the required control limits of 85-115%. After each five to

MDL may have been inappropriately high for the ten new recovery measurements, new control limits can

determination. If so, this could result in the be calculated using only the most recent 20-30 data

calculation of an unrealistically low MDL. If points. Also, the standard deviation (S) data should be

additional confirmation of the MDL is desired, used to established an ongoing precision statement for

reanalyze the seven replicate aliquots on two the level of concentrations included in the LFB. These

more nonconsecutive days and again calculate data must be kept on file and be available for review.

the MDL values for each day. An average of the

three MDL values for each analyte may provide

for a more appropriate MDL estimate. Concur- For all determinations the laboratory must analyze the

rently, determination of MDL in reagent water IPC solution (Section 7.8) and a calibration blank immerepresents a best case situation and does not diately following daily calibration, after every tenth

reflect possible matrix effects of real world sample (or more frequently, if required) and at the end of

samples. However, successful analyses of LFMs the sample run. Analysis of the IPC solution and calibra-

(Section 9.4) can give confidence to the MDL tion blank immediately following calibration must verify

value determined in reagent water. Typical that the instrument is within ±10% of calibration. Subsenew operator begins work or whenever there is a signifi9.3 Assessing Laboratory Performance (Mandatory)

9.3.1 Laboratory reagent blank (LRB) -- The laboratory

batch of 20 or fewer samples. LRB data are used to

assess contamination from the laboratory environment.

LRB values that exceed the MDL indicate laboratory or

reagent contamination should be suspected. Any determined source of contamination must be corrected and

the samples reanalyzed for the affected analytes after

acceptable LRB values have been obtained.

9.3.2 Laboratory fortified blank (LFB) -- The laboratory

batch of samples. Calculate accuracy as percent recovoutside the required control limits of 85-115%, that

analyte is judged out of control, and the source of the

problem should be identified and resolved before continuing analyses.

9.3.3 The laboratory must use LFB analyses data to

internal performance data become available (usually a

be developed from the percent mean recovery (x) and

Upper Control Limit = x + 3S

Lower Control Limit = x - 3S

9.3.4 Instrument performance check (IPC) solution --
R'

(Cs&C)

S

x 100

200.10-9 Revision 1.6 September 1997

quent analyses of the IPC solution must verify the 9.4.4 If the recovery of any analyte falls outside the

calibration within ±15%. If the calibration cannot be

verified within the specified limits, reanalyze the IPC

solution. If the second analysis of the IPC solution

confirms calibration to be outside the limits, sample

analysis must be discontinued, the cause determined

and/or in the case of drift the instrument recalibrated. All

samples following the last acceptable IPC solution must

be reanalyzed. The analysis data of the calibration blank

and IPC solution must be kept on file with the sample

analyses data.

9.3.5 The overall sensitivity and precision of this

method are strongly influenced by a laboratory's ability to

control the method blank. Therefore, it is recommended

that the calibration blank response be recorded for each

set of samples. This record will aid the laboratory in

assessing both its long- and short-term ability to control

the method blank.

9.4 Assessing Analyte Recovery and Data

Quality

9.4.1 Sample homogeneity and the chemical nature of

the sample matrix can affect analyte recovery and the

quality of the data. Taking separate aliquots from the

sample for replicate and fortified analyses can in some

cases assess these effects. Unless otherwise specified

by the data user, laboratory or program, the following

laboratory fortified matrix (LFM) procedure (Section

9.4.2) is required.

9.4.2 The laboratory must add a known amount of

each analyte to a minimum of 10% of the routine samples. In each case the LFM aliquot must be a duplicate

of the aliquot used for sample analysis and for total

recoverable determinations added prior to sample

preparation. For water samples, the added analyte

concentration must be the same as that used in the

laboratory fortified blank (Section 9.3.2).

9.4.3 Calculate the percent recovery for each analyte,

corrected for concentrations measured in the unfortified

sample, and compare these values to the designated

LFM recovery range of 75-125%. Recovery calculations

are not required if the concentration added is less than

25% of the unfortified sample concentration. Percent

recovery may be calculated in units appropriate to the

matrix, using the following equation:

where, R = percent recovery.

C = fortified sample concentration. S

C = sample background concentration.

S = concentration equivalent of analyte added

to sample.

designated LFM recovery range and the laboratory performance for that analyte is shown to be in control

(Section 9.3), the recovery problem encountered with the

LFM is judged to be either matrix or solution related, not

system related.

9.4.5 If analysis of LFM sample(s) and the test routines above indicate an operative interference and the

LFMs are typical of the other samples in the batch, those

samples that are similar must be analyzed in the same

manner as the LFMs. Also, the data user must be

informed when a matrix interference is so severe that it

prevents the successful analysis of the analyte or when

the heterogeneous nature of the sample precludes the

use of duplicate analyses.

9.4.6 Where reference materials are available, they

should be analyzed to provide additional performance

data. The analysis of reference samples is a valuable

tool for demonstrating the ability to perform the method

acceptably.

10.0 Calibration and Standardization

10.1 Initiate proper operating configuration of ICP-MS

instrument and data system. Allow a period of not less

than 30 min for the instrument to warm up. During this

process conduct mass calibration and resolution checks

using the tuning solution. Resolution at low mass is

indicated by nickel isotopes 60, 61, 62. Resolution at

high mass is indicated by lead isotopes 206, 207, 208.

For good performance adjust spectrometer resolution to

produce a peak width of approximately 0.75 amu at 5%

peak height. Adjust mass calibration if it has shifted by

more than 0.1 amu from unit mass.

10.2 Instrument stability must be demonstrated by

analyzing the tuning solution (Section 7.6) a minimum of

five times with resulting relative standard deviations of

absolute signals for all analytes of less than 5%.

10.3 Prior to initial calibration, setup proper instrument

software routines for quantitative analysis and connect

the ICP-MS instrument to the preconcentration apparatus. The instrument must be calibrated for the analytes

of interest using the calibration blank (Section 7.5.1) and

calibration standard (Section 7.4.1) prepared at one or

more concentration levels. The calibration solutions

should be processed through the preconcentration

system using the procedures described in Section 11.

10.4 Demonstration and documentation of acceptable

initial calibration is required before any samples are

analyzed. After initial calibration is successful, a calibration check is required at the beginning and end of each

period during which analyses are performed and at

requisite intervals.
Revision 1.6 September 1997 200.10-10

10.4.1 After the calibration has been established, it Note: For proper heating, adjust the temperature

must be initially verified for all analytes by analyzing the control of the hot plate such that an uncovered

IPC (Section 7.8). If the initial calibration verification Griffin beaker containing 50 mL of water placed

exceeds ±10% of the established IPC value, the analysis in the center of the hot plate can be maintained

should be terminated, the source of the problem identi- at a temperature approximately but no higher

fied and corrected, the instrument recalibrated, and the than 85EC. (Once the beaker is covered with a

new calibration verified before continuing analyses. watch glass the temperature of the water will rise

10.4.2 To verify that the instrument is properly calibrated

on a continuing basis, analyze the calibration blank

(Section 7.5.1) and IPC (Section 7.8) after every 10 about 20-mL by gentle heating at 85EC. Do Not Boil.

analyses. The results of the analyses of the standards This step takes about 2 h for a 100-mL aliquot with the

will indicate whether the calibration remains valid. If the rate of evaporation rapidly increasing as the sample

indicated concentration of any analyte deviates from the volume approaches 20 mL. (A spare beaker containing

true concentration by more than 15%, reanalyze the 20-mL of water can be used as a gauge.)

standard. If the analyte is again outside the 15% limit, the

instrument must be recalibrated and the previous 10 11.1.3 Cover the lip of the beaker with a watch glass to

samples reanalyzed. The instrument responses from the

calibration check may be used for recalibration purposes.

10.5 Internal Standardization -- Internal standardization must be used in all analyses to correct for instrument

drift and physical interferences. For full mass range

scans, a minimum of three internal standards must be

used. Internal standards must be present in all samples,

standards and blanks at identical levels. This may be

achieved by directly adding an aliquot of the internal

standards to the CAL standard, blank or sample solution

(Method A), or alternatively by mixing with the solution

prior to nebulization using a second channel of the

peristaltic pump and a mixing coil (Method B). The

concentration of the internal standard should be sufficiently high that good precision is obtained in the measurement of the isotope used for data correction and to

minimize the possibility of correction errors if the internal

standard is naturally present in the sample. Internal

standards should be added to blanks, samples and

standards in a like manner, so that dilution effects resulting from the addition may be disregarded.

Note: Bismuth should not be used as an internal

standard using the direct addition method (Method A, Section 10.5) because it is not efficiently

concentrated on the iminodiacetate column.

11.0 Procedure

11.1 Sample Preparation -- Total Recoverable

Elements

11.1.1 Add 2-mL(1+1) nitric acid to the beaker containing 100-mL of sample. Place the beaker on the hot plate

for solution evaporation. The hot plate should be located

in a fume hood and previously adjusted to provide evaporation at a temperature of approximately but no higher

than 85EC. (See the following note.) The beaker should

be covered with an elevated watch glass or other necessary steps should be taken to prevent sample contamination from the fume hood environment.

to approximately 95EC.)

11.1.2 Reduce the volume of the sample aliquot to

reduce additional evaporation and gently reflux the

sample for 30 min. (Slight boiling may occur, but vigorous boiling must be avoided.)

11.1.4 Allow the beaker to cool. Quantitatively transfer

the sample solution to a 100-mL volumetric flask, dilute

to volume with reagent water, stopper and mix.

11.1.5 Allow any undissolved material to settle overnight, or centrifuge a portion of the prepared sample until

clear. (If after centrifuging or standing overnight, the

sample contains suspended solids, a portion of the

sample may be filtered prior to analysis. However, care

should be exercised to avoid potential contamination

from filtration.) The sample is now ready for analysis.

Because the effects of various matrices on the stability of

diluted samples cannot be characterized, all analyses

should be performed as soon as possible after the

completed preparation.

11.2 Prior to first use, the preconcentration system

should be thoroughly cleaned and decontaminated using

0.2M oxalic acid.

11.2.1 Place approximately 500-mL 0.2M oxalic acid in

all the eluent/solution containers and fill the sample loop

with 0.2M oxalic acid using the sample pump (P4) at a

flow rate of 3-5 mL/min. With the preconcentration

system disconnected from the ICP-MS instrument, use

the pump program sequence listed in Table 2 to flush the

complete system with oxalic acid. Repeat the flush sequence three times.

11.2.2 Repeat the sequence described in Section

11.2.1 using 1.25M nitric acid and again using ASTM

type I water in place of the 0.2M oxalic acid.

11.2.3 Rinse the containers thoroughly with ASTM type

I water, fill them with their designated reagents (see

Figure 1) and run through the sequence in Table 2 once

to prime the pump and all eluent lines with the correct

reagents.
200.10-11 Revision 1.6 September 1997

11.3 Initiate ICP-MS instrument operating configuration. Tune the instrument for the analytes of interest

(Section 10).

11.4 Establish instrument software run procedures for

quantitative analysis. Because the analytes are eluted

from the preconcentration column in a transient manner,

it is recommended that the instrument software is configured in a rapid scan/peak hopping mode. The instrument

is now ready to be calibrated.

11.5 Reconnect the preconcentration system to the

ICP-MS instrument. With valves A and B in the off

position and valve C in the on position, load sample

through the sample loop to waste using pump P4 for 4

min at 4 mL/min. Switch on the carrier pump (P3) and

pump 1% nitric acid to the nebulizer of the ICP-MS

instrument at a flow rate of 0.8-1.0-mL/min.

11.6 Switch on the buffer pump (P2), and pump 2M

ammonium acetate at a flow rate of 1.0 mL/min.

11.7 Preconcentration of the sample may be achieved

by running through an eluent pump program (P1) sequence similar to that illustrated in Table 2. The exact

timing of this sequence should be modified according to

the internal volume of the connecting tubing and the

specific hardware configuration used.

11.7.1 Inject sample -- With valves A, B, and C on, load

sample from the loop onto the column using 1M ammonium acetate for 4.5 min at 4.0 mL/min. The analytes are

retained on the column, while the majority of the matrix

is passed through to waste.

11.7.2 Elute analytes -- Turn off valves A and B and

begin eluting the analytes by pumping 1.25M nitric acid

through the column at 4.0 mL/min, then turn off valve C

and pump the eluted analytes into the ICP-MS instrument

at 1.0 mL/min. Initiate ICP-MS software data acquisition

and integrate the eluted analyte profiles.

11.7.3 Column Reconditioning -- Turn on valve C to

direct column effluent to waste, and pump 1.25M nitric

acid, 1M ammonium acetate, 1.25M nitric acid and 1M

ammonium acetate alternately through the column at 4.0

mL/min. During this process, the next sample can be

loaded into the sample loop using the sample pump (P4).

11.8 Repeat the sequence described in Section 11.7

for each sample to be analyzed. At the end of the analytical run leave the column filled with 1M ammonium

acetate buffer until it is next used.

11.9 Samples having concentrations higher than the

established linear dynamic range should be diluted into

range with 1% HNO (v/v) and reanalyzed. 3

12.0 Data Analysis and Calculations

12.1 Analytical isotopes and elemental equations

recommended for sample data calculations are listed in

Table 3. Sample data should be reported in units of μg/L.

Do not report element concentrations below the determined MDL.

12.2 For data values less than 10, two significant

figures should be used for reporting element concentrations. For data values greater than or equal to 10, three

significant figures should be used.

12.3 Reported values should be calibration blank subtracted. If additional dilutions were made to any samples,

the appropriate factor should be applied to the calculated

sample concentrations.

12.4 Data values should be corrected for instrument

drift by the application of internal standardization. Corrections for characterized spectral interferences should be

applied to the data.

12.5 The QC data obtained during the analyses

provide an indication of the quality of the sample data

and should be provided with the sample results.

13.0 Method Performance

13.1 Experimental conditions used for single laboratory testing of the method are summarized in Table 4.

13.2 Data obtained from single laboratory testing of

the method are summarized in Tables 5 and 6 for two

reference water samples consisting of National Research

Council Canada (NRCC) Estuarine Water (SLEW-1) and

Seawater (NASS-2). The samples were prepared using

the procedure described in Section 11.1.1. For each

matrix, three replicates were analyzed and the average

of the replicates was used to determine the sample

concentration for each analyte. Two further sets of three

replicates were fortified at different concentration levels,

one set at 0.5 Fg/L, the other at 10 μg/L. The sample

concentration, mean percent recovery, and the relative

standard deviation of the fortified replicates are listed for

each method analyte. The reference material certificate

values are also listed for comparison.

14.0 Pollution Prevention

14.1 Pollution prevention encompasses any technique

that reduces or eliminates the quantity or toxicity of waste

at the point of generation. Numerous opportunities for

pollution prevention exist in laboratory operation. The

EPA has established a preferred hierarchy of environmental management techniques that place pollution pre-
Revision 1.6 September 1997 200.10-12

vention as the management option of first choice. Whenever feasible, laboratory personnel should use pollution

prevention techniques to address their waste generation

(e.g., Section 7.8). When wastes cannot be feasibly

reduced at the source, the Agency recommends recy--

cling as the next best option.

14.2 For information about pollution prevention that

may be applicable to laboratories and research institutions, consult Less is Better: Laboratory Chemical Management for Waste Reduction, available from the American Chemical Society's Department of Government Relations and Science Policy, 1155 16th Street N.W.,

Washington, D.C. 20036, (202)872-4477.

15.0 Waste Management

15.1 The Environmental Protection Agency requires

that laboratory waste management practices be conducted consistent with all applicable rules and regulations. The Agency urges laboratories to protect the air,

water, and land by minimizing and controlling all releases

from hoods and bench operations, complying with the

letter and spirit of any sewer discharge permits and

regulations, and by complying with all solid and hazardous waste regulations, particularly the hazardous waste

identification rules and land disposal restrictions. For

further information on waste management, consult The

Waste Management Manual for Laboratory Personnel,

available from the American Chemical Society at the

address listed in Section 14.2.

16.0 References

1. Siraraks, A., H.M. Kingston, and J.M. Riviello,

Anal Chem. 62,1185 (1990).

2. Heithmar, E.M., T.A. Hinners, J.T. Rowan, and

J.M. Riviello, Anal Chem., 62, 857 (1990).

3. Gray A.L. and A.R. Date, Analyst, 108, 1033

(1983).

4. Houk, R.S., et al. Anal. Chem., 52, 2283 (1980).

5. Houk, R.S., Anal.Chem., 58, 97A (1986).

6. J. J. Thompson and R.S. Houk, Appl. Spec., 41,

801 (1987).

7. OSHA Safety and Health Standards, General

Industry, (29 CFR 1910), Occupational Safety

and Health Administration, OSHA 2206, (Revised, January 1976).

8. Safety in Academic Chemistry Laboratories,

American Chemical Society Publication, Committee on Chemical Safety, 3rd Edition, 1979.

9. Code of Federal Regulations 40, Ch. 1, Pt. 136

Appendix B.
200.10-13 Revision 1.6 September 1997

17.0 Tables, Diagrams, Flowcharts, and Validation Data

Table 1. Total Recoverable Method Detection Limits for Reagent Water

Recommended MDL1

Element Analytical Mass Fg/L

Cadmium 111 0.041

Cobalt 59 0.021

Copper 63 0.023

Lead 206, 207,208 0.074

Nickel 60 0.081

Uranium 238 0.031

Vanadium 51 0.014

 Determined using 10-mL sample loop. 1

Table 2. Eluent Pump Programming Sequence for Preconcentration of Trace Elements

Time Flow Valve Valve

(min) (mL/min) Eluent A,B C

0.0 4.0 1M ammonium acetate ON ON

4.5 4.0 1.25M nitric acid ON ON

5.1 1.0 1.25M nitric acid OFF ON

5.5 1.0 1.25M nitric acid OFF OFF

7.5 4.0 1.25M nitric acid OFF ON

8.0 4.0 1M ammonium acetate OFF ON

10.0 4.0 1.25M nitric acid OFF ON

11.0 4.0 1M ammonium acetate OFF ON

12.5 0.0 OFF ON

Table 3. Recommended Analytical Isotopes and Elemental Equations for Data Calculations

Element Isotope Elemental Equation Note

Cd 106, 108, 111, 114 (1.000)( C)-(1.073)[( C)-(0.712)( C)] (1) 111 108 106

Co 59 (1.000)( C) 59

Cu 63, 65 (1.000)( C) 63

Pb 206, 207, 208 (1.000)( C)+(1.000)( C)+(1.000)( C) (2) 206 207 208

Ni 60 (1.000)( C) 60

U 238 (1.000)( C) 238

V 51 (1.000)( C) 51

C - calibration blank subtracted counts at specified mass.

(1) - correction for MoO interference. An additional isobaric elemental correction should be made if palladium is present.

(2) - allowance for isotopic variability of lead isotopes.

NOTE: As a minimum, all isotopes listed should be monitored. Isotopes recommended for analytical determination are italized.
Revision 1.6 September 1997 200.10-14

Table 4. Experimental Conditions for Single Laboratory Validation

Chromatography

Instrument Dionex chelation system

Preconcentration column Dionex MetPac CC-1

ICP-MS Instrument Conditions

Instrument VG PlasmaQuad Type I

Plasma forward power 1.35 kW

Coolant flow rate 13.5 L/min

Auxiliary flow rate 0.6 L/min

Nebulizer flow rate 0.78 L/min

Internal standards Sc, Y, In, Tb

Data Acquisition

Detector mode Pulse counting

Mass range 45-240 amu

Dwell time 160 Fs

Number of MCA channels 2048

Number of scan sweeps 250

Table 5. Precision and Recovery Data for Estuarine Water (SLEW-1)

Sample Spike Average Spike Average

Certificate Conc. Addition Recovery RSD Addition Recovery RSD

Analyte (Fg/L) (Fg/L) (Fg/L) (%) (%) (Fg/L) (%) (%)

Cd 0.018 <0.041 0.5 94.8 9.8 10 99.6 1.1

Co 0.046 0.078 0.5 102.8 4.0 10 96.6 1.4

Cu 1.76 1.6 0.5 106.0 2.7 10 96.0 4.8

Pb 0.028 <0.074 0.5 100.2 4.0 10 106.9 5.8

Ni 0.743 0.83 0.5 100.0 1.5 10 102.0 2.1

U -- 1.1 0.5 96.7 7.4 10 98.1 3.6

V -- 1.4 0.5 100.0 3.2 10 97.0 4.5

-- No certificate value

Table 6. Precision and Recovery Data for Seawater (NASS-2)

Sample Spike Average Spike Average

Certificate Conc. Addition Recovery RSD Addition Recovery RSD

Analyte (Fg/L) (Fg/L) (Fg/L) (%) (%) (Fg/L) (%) (%)

Cd 0.029 <0.041 0.5 101.8 1.0 10 96.4 3.7

Co 0.004 <0.021 0.5 98.9 3.0 10 99.2 1.7

Cu 0.109 0.12 0.5 95.8 2.3 10 93.1 0.9

Pb 0.039 <0.074 0.5 100.6 8.5 10 92.1 2.6

Ni 0.257 0.23 0.5 102.2 2.3 10 98.2 1.2

U 3.00 3.0 0.5 94.0 0.7 10 98.4 1.7

V -- 1.7 0.5 104.0 3.4 10 109.2 3.7

--No certificate value
Waste Waste Waste

A

B

B

A

C

Chelating

Column

10 mL

Loop

Buffer

Pump

Eluent

Pump

Carrier

Pump

P/STALTIC

Pump

Sample

1MNHOAc 1.25 MNitricAcid

1%Nitric Acid

P3

ICP-MS

Mixing Tee

Off On

P2 P4 P1

4

2MNHOAc

4

Figure 1. Configuration of Preconcentration System.

200.10-15 Revision 1.6 September 1997