QA/QC and Method PerformanceConsiderations for Chemical Testing:ConsiderationsforChemicalTesting:Samples Impacted by HF FluidsEPA Hydraulic Fracturing Technical WorkshopEPAHydraulicFracturingTechnicalWorkshopArlington, VirginiaFebruary 24 - 25, 2011David Thal – Senior Technical ChemistEnvironmental Standards, Inc.Today’s DiscussionQA/QC for EPA-funded projects as a modelCritical elements of environmental testing QA/QCTypes of analytical methods being routinely appliedTypes of QA/QC demonstrations and QA/QC samplesRough Guide: What QA/QC is needed?Specific information on interferences encounteredSummary2Elements of QA/QCGuidance on Systematic Planning Using the DataQuality Objectives Process EPA QA/G-4“The principal DQIs are precision, bias (accuracy),representativeness, completeness, comparability, andsensitivity.”EPA Requirements for Quality Assurance ProjectPlans EPA EPA QA/R-5References “PARCC” parameters3Are the PARCC Parameters Sufficient?Precision (Test-retest reliability)Accuracy (Comparison of result to consensus value)Representativeness (Does sample reflect population?)epresentativeness(Doessamplereflectpopulation?)Completeness (Data of good quality on a sufficient percentage ofsamples?)Comparability (Does the data set make sense within broader dataomparability(Doesthedatasetmakesensewithinbroaderdatasets?)What aboutSensitivity?(EPA QA/G-4 mentions it. Among 10 states and agency guidancedocuments checked only Connecticut lists it – as PARCCS)What aboutSelectivity?(B i d i th th d th i d f l ti l h i t )(Buriedinthe methods orthe minds ofanalyticalchemists.)SPARCCS would be a better mnemonic.4Frequently Encountered Types of Method –Related to Shale GasRelatedtoShaleGasClassical Chemistry- pH, TKN, Anions, Alkalinity, Hardness, HEM (oiland grease)G Ch t hM th Eth G li Di l d OilGasChromatography-Methane,Ethane,Gasoline,DieselandOilRange Organics,Metals Determinations- Alkali Metals. Divalent and other metalsi l di MincludingMercury.(ICP-AES, ICP-MS & CVAA)NORM- Gamma Spectrometry, Gross alpha, Gross beta.Specialties–Alkoxyalkylphenols, organic acids other organics.(GC-MS, LC-MS/MS)5Types of QA/QC Samples and DemonstrationsI iti l D t ti f C bilitInitialDemonstration ofCapabilityMethod Detection Limit StudiesStandard Reference Materials (Natural matrix if available!)StandardReferenceMaterials(Naturalmatrixifavailable!)Blind Performance Evaluation SamplesTrip Blanks (VOCs)Equipment BlanksInstrument BlanksLaboratory Method BlanksLaboratoryMethodBlanksLaboratory Control SamplesMatrix Spikes6Laboratory Duplicates or Matrix Spike DuplicatesQA/QC – Expect Good PracticesQA/QC CheckClassicalChemistryGC-VOC(&GRO)GC-SVOCICP-AES/ICP-MSNORMGC/LC-MS SVOCInitial Demonstration of CapabilityYes Yes Yes YesSomeYesMethod Detection Limit StudiesMost Yes Yes Yes(MDA)YesStandard Reference MaterialsYes Yes Yes Yes Yes* YesBlind PE SamplesYes Yes Yes YesSomeYesTrip Blanks (VOCs)YesEquipmentBlanksRareYesYesYesRareYesEquipmentInstrument BlanksYes Yes Yes YesMethod BlanksYes Yes Yes Yes Yes YesLaboratory Control SamplesYes Yes Yes Yes Yes YesMatrix Spikes.Some Yes Yes Yes Yes YesLaboratory Dup or Matrix Spike Dups.Yes Yes Yes Yes Yes YesDilution CheckYesPost Dilution SpikeYes7PostDilutionSpikeYesExample Data SetT tA i N h ill id d d t t i l diTestAmericaNashville providedadata setincluding(depending on the analysis) up to 542 samples.Samples were from 5 sites across the Marcellus ShaleSampleswerefrom5sitesacrosstheMarcellusShaleformation.Most frequent test was Chloride.Oth t t t i l d d M t l GRO DROOthertestparametersincluded:Metals,GRO,DRO,ORO, 2-butoxyethanol, alkalinity, ammonia as nitrogen,arsenic, barium, bicarbonate, btu content, HEM, MBAS,Oil and Grease, Sulfate, Sulfide, TSS, TDS, TPH.These samples were examined for potential interferenceslisted in methods and based on experience8listedinmethods,andbasedonexperience.InterferencesDissol ed SolidsHighl minerali ed aters containing significantDissolvedSolids-Highlymineralizedwaterscontainingsignificantconcentrations of calcium, magnesium, chloride and/or sulfate.Total residue should be limited to about 200 mg. (On a 100 mL samplethis would be 2000 mg/L 3 4% of the anecdotal samplesthiswouldbe2000mg/L,3.4%oftheanecdotalsamples.Alkalinity- (Titrimetric Method 310.1) and pH. Oil and grease maycoat the electrode causing sluggish response.For samples having high concentrations of mineral acids, methodForsampleshavinghighconcentrationsofmineralacids,methodmodifications are needed (titrate to an electrometric endpoint of pH3.9,using ASTM Standard, D- 067, Method D or superseding methods.Anions (Chloride, Fluoride, Bromide, Nitrite, Nitrate, Phosphate,Sf )fulate)- Any species with a retention time similar to that othedesired anion will interfere. Example, high levels of organic acids thatmay interfere with inorganic anion analysis may be present. Severalorganic acidhomopolymerspolymers andtelomersare used in9organicacidhomopolymers,polymersandtelomersareusedinfracturing fluids.Interferences (Cont.)Total Kjeldahl Nitrogen(Automated Colorimetry 351.2) - High nitrateconcentrations (10X or more than the TKN level) result in low TKN values.Ion Selecitve Electrode 351.4): The reaction between nitrate and ammoniab t d b th f i h i ( hl id f ) tcanbe preventedbythe use ofan anion exchange resin(chlorideform)toremove the nitrate prior to the TKN analysis.Barium(ICP-AES or MS, e.g. 200.7, 6010, 6020) - The total recoverablesample digestion procedure willsolubilizeand hold in solution only minimalsampledigestionprocedurewillsolubilizeandholdinsolutiononlyminimalconcentrations of barium in the presence of free sulfate.Metals by ICP-AES(e.g., 200.7, 6010) - High viscosity and low surfacetension can impair sample nebulization and transport processes, causingsignificant inaccuracies esp. in samples w/ high dissolved solids or highacid concentrations.Bariumcan be an interference above the SIC level for ICP-AES. Bariumcan cause interferences both in the metals analysis and the NORM10cancauseinterferencesbothinthemetalsanalysisandtheNORManalyses. (Co-precipitation.)Interferences (Cont.)ICP-MS Interference Check Standard (concentration in check std):Ca (300 mg/L); Fe (250 mg/L); Mg (100.0 mg/L); Na (250 mg/L)250.0; K (100 mg/L); Cl (2000 mg/L).3.0% of 439 samples exceeded the Ca check standard level.Higher literature values exceed the check standard concentration100-fold.One of 74 samples exceeded the Fe check standard level.1.3% of 381 samples exceeded the Mg check standard level.Higher values reported in the literature exceed 25 times theHighervaluesreportedintheliteratureexceed25timestheinterference check standard level.10% of the samples exceeded the Na check standard level.4% exceeded the K check standard level114%exceededtheKcheckstandardlevel.1.8% of the 542 samples exceeded the Cl check standard level.Summary – and some thoughts to spurdiscussionM t d d l ti l th d l h th ill f l iMany standardanalyticalmethods apply;however,they willperform poorlyinsome cases involving high levels of interferents. The interferences are wellcharacterized, but a careful evaluation of the entire data set is needed tounderstand thepotential biases.For Metals, ICP-MS alone is not a good fit.ICP-Atomic Emission Spectrometry isneeded to overcome many interferences.Total Dissolved Solids data should be scrutinized.Use field duplicates and evaluate carefully.If anion data set does not make sense, consider method of standard additions.Watch barium levels.If th t i t t hi h i l ti l h i t t l tIfthey are notconsistent, orhighengage a senior analyticalchemistto evaluate.Watch sulfate levels.They can cause a low bias in barium.Watch nitrate levels12Watchnitratelevels.They can cause low bias in TKN.Questions?E i t l St d d IEnvironmentalStandards,Inc.“Setting the Standards for Innovative Environmental Solutions”Headquarters1140 Valley Forge RoadVirginia1208 East Market StreetTennessee1013 Brentwood WayP.O. Box 810Valley Forge, PA 19482Tel:610.935.5577solutions@envstd.comCharlottesville, VA 22902Tel:434.293.4039solutions-virginia@envstd.comWeb:www.envstd.comKingston, TN 37763Tel:865.376.7590solutions-tn@envstd.com13