Accutest LaboratoriesField and Analytical ChallengesPractical Quantitation Limits, MethodDetection Limits Interferences and Dil tionDetectionLimits,InterferencesandDilutionChallengesFebruary 24-25 2011February,2425,2011Kesavalu M. Bagawandoss, Ph.D., J.D.(Doss)Introduction• Fracturing fluids vary significantly in consistency andviscosity.•Samples received were predominantly representativeSamplesreceivedwerepredominantlyrepresentative.• Samples received in our laboratory were eitherprepared the same dayof receipt or within a dayafterp y p y• Matrices varied from DI water like consistency to athick paint like consistency (all samples were freeflowing).• Samples were preserved per regulatory requirementsother than VOA’s.2Parameters and Methods• Acrylamide – SW846 – 8316 • VOA’s – EPA Method 624• Metals – Method 200.8 / 245.1• Cyanide/ Weak anddissociable Total–SM 4500• SVOA’s – EPA Method 625• Pesticides/ PCB’s – EPAMethod 608dissociable,TotalSM4500CN E & I• Fecal and Total Coliform – SM9222D & BMethod608• 2,3,7,8 – TCDD – EPA Method1613BHalo Acetic AcidsEPA• Total Phenolics – EPA Method420.1•Herbicides–SW846–8151•HaloAceticAcids–EPAMethod 552.3• 1, 2 – Dibromoethane – EPAMethod 504 1•Herbicides–SW846–8151• Ion Chromatography – EPAMethod 300Method504.1• Residual Chlorine–SM 4500CL G3Fracturing Fluid Analyses Parameters500 Series4Fracturing Fluid Analyses Parameters600 Series5Fracturing Fluid Analyses Parameters600 Series (continued)6Fracturing Fluid Analyses Parameters600 Series (continued)7Fracturing Fluid Analyses Parameters600 Series (continued)8F t i Fl id A l P tFracturingFluidAnalysesParameters600 Series (continued)9Fracturing Fluid Analyses Parameters600 Series (continued)10Fracturing Fluid Analyses ParametersInorganic11Fracturing Fluid Analyses ParametersSW84612PQL’s and MDL’s• The PQL’s were achieved for most of the Frac Fluidsexcept for the highlyviscous samples.gy p• The target PQL’s listed in the individual methods weretili duze.• The MDL’s used for the study were those obtained forwaters.13PQL’s and MDL’sRecommendations for highly viscous Frac fluids• Use of Liquid/Liquid extraction techniques.• Use GPC cleanup techniques (although samples are liquids).• Use of above techniques may or may not influence theinteractions on chromatographic columns.14Interferences and Dilution ChallengesMatrix Spike/ Surrogate Spike interactions:• Spiking viscous liquids does not yield much information due todilutions that are required.• Spikes performed on non viscous matrices yielded adequaterecoveries.• Acid Surrogate recoveries in the SVOA analyses are affectedeven though the base surrogate recoveries are acceptable.15Interferences and Dilution ChallengesIssues encountered due to viscosity:Issuesencounteredduetoviscosity:• Chromatographic columns were affected (SVOA’s).GC/MS Ion sources were affected•GC/MSIonsourceswereaffected.• Ion Chromatographic columns were clogged and their phaseswere alteredwerealtered.• Even though matrix effects are inevitable, Tentatively identifiedcompounds may or may not be detected in these samplescompoundsmayormaynotbedetectedinthesesamples.• Metals analyses were not affected due to digestions performedusing acidsusingacids.16Interferences and Dilution Challenges•Dilution factors ranged from 2 to 50 fold for theDilutionfactorsrangedfrom2to50foldfortheviscous fluids depending on their viscosity.•Interference effects are due to the viscous nature orInterferenceeffectsareduetotheviscousnatureorcomposition of the fluids.E l MS/MSD i ld b ff t d•ExampleMS/MSDrecoveries wouldbe affected–anexample is in the VOA analysis, the gases recoveredat almost 100 percent but the mid range compoundsatalmost100percent,butthemidrangecompoundsrecovered at less than 50 percent and the higherboiling compounds recovered at around 60 percentboilingcompoundsrecoveredataround60percent.17Interferences and Dilution Challenges• Chromatographic columns would experience activep psurfaces wherein continuing calibrations would notpass QC criteria.• Required injection port maintenance after eachsequence.• Ion Chromatographic columns would have to bereplaced if appropriate dilutions are not made beforepp panalysis.•Some fluids would exhibit foaming and the samplesSomefluidswouldexhibitfoamingandthesampleswould have to be handled appropriately.18Summary•Not all frac fluids are made equalNotallfracfluidsaremadeequal.• Care should be exercised during analysis to manageviscous samples.• Sample preservations are not a problem.• Analytical parameters must be predefined.E t ti t b d fi d•Expectations mustbedefined.• If constituents of frac fluids must be determined, then,other methodologies must be developed.19