Accutest Laboratories

Field and Analytical Challenges

Practical Quantitation Limits, Method 

Detection Limits Interferences and Dil tDetection Limits, Interferences and Dilut

Challenges

February 24 February, 24-25 2011 25, 2011

Kesavalu M. Bagawandoss, Ph.D., J.D.

(Doss)
Introduction

• Fracturing fluids vary significantly in consistency 

viscosity.

• Samples received were predominantly represen

Samples received were predominantly represen

• Samples received in our laboratory were either 

pp y p 

repared the same day of receipt or within a da

• Matrices varied from DI water like consistency t

thick paint like consistency (all samples were freflowing).

• Samples were preserved per regulatory require

other than VOA’s.
Parameters and Methods

• Acrylamide – SW846 – 8316 • VOA’s – EPA Method • Metals – Method 200.8 / 245.1• Cyanide/ Weak and 

dissociable Total

– SM 4500

• SVOA’s – EPA Metho• Pesticides/ PCB’s – E

dissociable, Total SM 4500 Method 608

CN E & I

• Fecal and Total Coliform – SM 

9222D & B

Method 608

• 2,3,7,8 – TCDD – EP

1613B

Halo Acetic Acids E

• Total Phenolics – EPA Method 

420.1

• Herbicides

– SW846

– 8151

• Halo Acetic Acids

– E

Method 552.3

• 1, 2 – Dibromoethane 

• Herbicides

– SW846

– 8151 Method 504 1

• Ion Chromatography – EPA 

Method 300

Method 504.1

• Residual Chlorine 

– SM 4500

CL G
Fracturing Fluid Analyses Parameter

500 Series
Fracturing Fluid Analyses Parameter

600 Series
Fracturing Fluid Analyses Parameter

600 Series (continued)
Fracturing Fluid Analyses Parameter

600 Series (continued)
Fracturing Fluid Analyses Parameter

600 Series (continued)
F t i Fl id A l P t Frac

turing Fl

uid

Analyses 

Parame

ter

600 Series (continued)
Fracturing Fluid Analyses Parameter

600 Series (continued)
Fracturing Fluid Analyses Parameter

Inorganic
Fracturing Fluid Analyses Parameter

SW846
PQL’s and MDL’s

• The PQL’s were achieved for most of the Frac F

excep gy p t for the highly viscous samples.

• The target PQL’s listed in the individual method

utili d ze .

• The MDL’s used for the study were those obtain

waters.
PQL’s and MDL’s

Recommendations for highly viscous Frac fluids• Use of Liquid/Liquid extraction techniques. • Use GPC cleanup techniques (although samples are liqu• Use of above techniques may or may not influence the 

interactions on chromatographic columns.
Interferences and Dilution Challenge

Matrix Spike/ Surrogate Spike interactions:• Spiking viscous liquids does not yield much information d

dilutions that are required.

• Spikes performed on non viscous matrices yielded adequ

recoveries.

• Acid Surrogate recoveries in the SVOA analyses are affe

even though the base surrogate recoveries are acceptab
Interferences and Dilution Challenge

Issues encountered due to viscosity: Issues encountered due to viscosity:• Chromatographic columns were affected (SVOA’s).• GC/MS Ion sources were affected GC/MS Ion sources were affected.

• Ion Chromatographic columns were clogged and their ph

were altered were altered.

• Even though matrix effects are inevitable, Tentatively ide

compounds may or may not be detected in these samplecompounds may or may not be detected in these sample

• Metals analyses were not affected due to digestions perfo

using acids using acids.
Interferences and Dilution Challenge

• Dilution factors ranged from 2 to 50 fold for the Dilution factors ranged from

2 to 50 fold for the

viscous fluids depending on their viscosity.

• Interference effects are due to the viscous natu

Interference effects are due to the viscous natu

composition of the fluids.

• E l MS/MSD i ld b ff t d Example MS/MSD recoveries would

be affec

t

e

d

example is in the VOA analysis, the gases reco

at almost 100 percent but the mid range compoat almost 100 percent, but the mid range compo

recovered at less than 50 percent and the highe

boiling compounds recovered at around 60 percboiling compounds recovered at around 60 perc
Interferences and Dilution Challenge

• Chromato

gp p ra

phic columns would ex

perience ac

surfaces wherein continuing calibrations would pass QC criteria.

• Required injection port maintenance after each 

se

quence.

• Ion Chromatographic columns would have to be 

re

p pp p laced if appro

priate dilutions are not made b

analysis.

• Some fluids would exhibit foaming and the sam

Some fluids would exhibit foaming and the sam

would have to be handled appropriately. 
Summary

• Not all frac fluids are made equal Not all frac fluids are made equal.

• Care should be exercised during analysis to ma

viscous samples.

• Sample preservations are not a problem.• Analytical parameters must be predefined.• E t ti t b d fi d Expectations must be defined.

• If constituents of frac fluids must be determined

other methodologies must be developed.