2021.03.08_CCO.p11_ChemoursPresentationOnBranched&LinearIsomers

Identification and Quantitationof Branched and Linear Isomers ofPerfluoroalkyl Ether Carboxylic Acids8 March 2021
AgendaToday’s Objective:Resolve the issue of the potential presence of the linear isomers PFMOPrA and PFMOBA and demonstrate that only the branched isomers should be analyzed in samples related to the Fayetteville Works FacilityPresentation Overview:• Background• Chromatography and Mass Spectrometry• Analysis of PMPA and PEPA Solutions by EPA Method 533• Re-analysis of Groundwater and Surface Water Samples by EPA Method 533• Re-analysis of Residential Drinking Water Samples by EPA Method 537.1 Mod• Summary and Key Messages28-Mar-2021
Key Messages3•Isomers– Branched: PMPA & PEPA Chemours chemistry– Linear: PFMOPrA & PFMOBAnot Chemours chemistry• PMPA and PEPA can be analytically separated from the corresponding linear isomers– Standard analytical methods may show a small false positive response for PFMOPrA if a large amount of PMPA is present• The concentration of linear isomers is 190 to 1,000 times lower than the corresponding branched isomer in groundwater, surface water and drinking water samples• Analysis of branched isomers only is appropriate for samples related to the Facility
4Background8-Mar-2021
Background58-Mar-2021Branched IsomersLinear IsomersPEPA: perfluoro‐2‐ethoxypropionic acidPFMOBA: perfluoro‐4‐methoxybutanoic acidPMPA: perfluoro‐2‐methoxypropionic acidPFMOPrA: perfluoromethoxypropionic acidProduction pathway chemistries at the Facility are not expected to generate the linear isomers.PMPA / PFMOPrAPEPA / PFMOBAPEPAC5HF9O3mw=279 CASN: 267239‐61‐2PFMOBAC5HF9O3mw=279 CASN: 863090‐89‐5COOHCF3OCFCF3CF2CF3OCOOHCF2CF2CF2PMPAC4HF7O3mw=229 CASN: 13140‐29‐9PFMOPrAC4HF7O3mw=229 CASN: 377‐73‐1COOHCF3OCFCF3COOHCF3OCF2CF2
Background (continued)• PMPA and PEPA, but not PFMOPrA and PFMOBA, are reported by Chemours’ contract laboratories– Eurofins TestAmerica-Sacramento (Sacramento, CA)– Eurofins Lancaster Laboratories Environmental (Lancaster, PA)• Prior to 2021, PFMOPrA and PFMOBA, but not PMPA and PEPA, were reported by DEQ’s contract laboratory– GEL Laboratories (Charleston, SC)• DEQ requested the use of improved analytical conditions (chromatography and mass spectrometry) to assess the potential presence of linear isomers in the branched standards and in environmental samples– letter dated October 2, 202068-Mar-2021
7Chromatography andMass Spectrometry(work conducted by Dr. Mark Strynar of USEPA)8-Mar-2021
Chromatography and Mass Spectrometry88-Mar-2021• The isomer pairs (PMPA/PFMOPrA and PEPA/PFMOBA) are not resolved well chromatographically by existing analytical methods (EPA Method 537.1 Mod, EPA Method 533, the Table 3 Method, the Table 6 Method)• The purpose of this part of the work was to develop chromatographic conditions to clearly resolve the isomer pairs, then demonstrate which mass transitions apply to each member of the pair–PMPA has a unique mass transition, PFMOPrA does not–PEPA and PFMOBA have unique mass transitions• Following that, the purity of the individual standards for each compound was assessed–The branched isomer standards do not contain the corresponding linear isomers at detectable levels
Chromatographic Separation98-Mar-2021PMPA PEPAPFMOPrA PFMOBA
Mass Transitions for PMPA / PFMOPrAMolecular weight = 229108-Mar-2021PMPA 229 → 185 229 → 85 185 → 119 185 → 85 185 → 69PFMOPrA -- 229 → 85 -- -- --AnalyteMass Transitions (m/z)Precursor Ion Transitions Product Ion Transitions- PMPA has a unique mass transition- PFMOPrA does notMajor transitionMinor transition
Mass Transitions: PMPA and PFMOPrAMolecular weight = 229118-Mar-2021PFMOPrAPMPAMass Transition: 229→85the major transition for PFMOPrAa minor transition for PMPAMass Transition: 229→185the major transition for PMPA1198569
Chromatographic Separation128-Mar-2021PMPAPFMOPrA
Mass Transitions: PMPA and PFMOPrAMolecular weight = 229138-Mar-2021Mass Transition: 229→185Mass Transition: 185→119Mass Transition: 185→85Mass Transition: 185→69
Mass Transitions: PMPA and PFMOPrAMolecular weight = 229148-Mar-2021PFMOPrAPMPAMass Transition: 229→85
Mass Transitions for PMPA / PFMOPrAMolecular weight = 229158-Mar-2021PMPA 229 → 185 229 → 85 185 → 119 185 → 85 185 → 69PFMOPrA -- 229 → 85 -- -- --AnalyteMass Transitions (m/z)Precursor Ion Transitions Product Ion TransitionsPMPA has a unique mass transition, PFMOPrA does notWhen analyzing for PFMOPrA, the presence of PMPA may give a false positive if the chromatographic conditions do not fully resolve PMPA/PFMOPrA
Mass Transitions for PEPA / PFMOBAmolecular weight = 279168-Mar-2021- PEPA and PFMOBA each have unique mass transitionsPEPA 279 → 235 -- 235 → 135 235 → 119 235 → 69PFMOBA -- 279 → 85 -- -- --AnalyteMass Transitions (m/z)Precursor Ion Transitions Product Ion Transitions
Mass Transitions: PEPA and PFMOBAMolecular weight = 279178-Mar-2021PFMOBAPEPAMass Transition: 279→85the major transition for PFMOBAMass Transition: 279→235the major transition for PEPA13511969
Chromatographic Separation188-Mar-2021PEPAPFMOBA
Mass Transitions: PEPA and PFMOBAMolecular weight = 279198-Mar-2021PFMOBAMass Transition: 235→135Mass Transition: 235→119Mass Transition: 235→69Mass Transition: 279→185Mass Transition: 279→235
Mass Transitions: PEPA and PFMOBAMolecular weight = 279208-Mar-2021PFMOBAMass Transition: 279→85
PMPA Standard (Chemours)218-Mar-2021Percentageof TotalAnalyte Area Count Area CountPMPA 53,035 99.16%PEPA 317 0.59%PFMOBA 131 0.24%Total Area Count 53,483PMPAPEPA PFMOBA
PEPA Standard (Chemours)228-Mar-2021PMPAPFMOPrAPEPAPercentageof TotalAnalyte Area Count Area CountPEPA 43,369 97.93%PMPA 427 0.96%PFMOPrA 490 1.11%Total Area Count 44,286
PFMOPrA Standard (SynQuest)238-Mar-2021PMPAPFMOPrAPercentageof TotalAnalyte Area Count Area CountPFMOPrA 32,163 97.72%PMPA 749 2.28%Total Area Count 32,912
PFMOBA Standard (SynQuest)248-Mar-2021Percentageof TotalAnalyte Area Count Area CountPFMOBA 14,465 93.30%PMPA 220 1.42%PFMOPrA 285 1.84%PEPA 534 3.44%Total Area Count 15,504PFMOBAPMPAPFMOPrAPEPA
PMPA PFMOPrA PEPA PFMOBAPMPA Chemours 99.16% 0.00% 0.59% 0.24%PEPA Chemours 0.96% 1.11% 97.93% 0.00%PFMOPrA SynQuest 2.28% 97.72% 0.00% 0.00%PFMOBA SynQuest 1.42% 1.84% 3.44% 93.30%% of Total Ion CountSingle-Component StandardSupplierSummary of Standards Purity258-Mar-2021The branched isomer standards do not contain any detectable levels of the corresponding linear isomers.
26Analysis of PMPA and PEPA Solutions by EPA Method 533(work conducted by TestAmerica and Lancaster)8-Mar-2021
Analysis of PMPA/PEPA Solutionsby EPA Method 533278-Mar-2021• Create solutions of the branched isomers from the Chemours standards• Analyze by EPA Method 533, which looks for the linear isomers only– We know that the corresponding linear isomers are absent, as just shown by the analysis of the individual standards• Note that the chromatography for this method is not designed to separate PMPA/PFMOPrA and PEPA/PFMOBA
Analysis of PMPA Solutions by EPA Method 533288-Mar-2021PFMOPrA(ng/L)Ratio ofPMPA to PFMOPrAPFMOPrA(ng/L)Ratio ofPMPA to PFMOPrA50 ng/L < 2.0 > 25:1 < 2.0 > 25:11,000 ng/L 3.5 290:1 < 2.0 > 500:120,000 ng/L 34 590:1 < 2.0 > 10,000:1Average Ratio = 440:1PMPA ConcentrationTestAmerica Lancaster•TestAmerica “detects” a very small amount of “PFMOPrA” in PMPA solutions >1,000 ng/L•This is a result of the small response of PMPA in the 229→85 mass transiƟon monitored for PFMOPrA•PFMOPrA is not present, therefore, this detection of PFMOPrA is a false positive•Approximately 1 ng/L PFMOPrA is falsely detected per 440 ng/L PMPA•Lancaster does not see a false positive detection of PFMOPrA from PMPA•Lancaster’s chromatographic conditions provide better separation of PMPA and PFMOPrA
Analysis of PEPA Solutions by EPA Method 533298-Mar-2021PFMOBA(ng/L)Ratio ofPEPA to PFMOBAPFMOBA(ng/L)Ratio ofPEPA to PFMOBA50 ng/L < 2.0 > 25:1 < 2.0 > 25:11,000 ng/L < 2.0 > 500:1 < 2.0 > 500:120,000 ng/L < 2.0 > 10,000:1 < 2.0 > 10,000:1PEPA ConcentrationTestAmerica Lancaster•Neither TestAmerica nor Lancaster detects PFMOBA in the PEPA solutions•There are no false positive detections of PFMOBA from PEPA
30Re-Analysis of Groundwater and Surface Water Samples by Method 533(work conducted by TestAmerica and Lancaster)8-Mar-2021
Groundwater and Surface Water Samples318-Mar-2021Location Sample ID Sample Date NotesOutfall 002 66 25 O00210 2/10/2020 On-site outfall. Grab sampleBladen-1D 450 120 CAP2Q20-BLADEN-1D-050620 5/6/2020 Off-site well in Black Creek Aquifer. Grab samplePW-06 1,600 580 CAP1Q20-PW-06-020620 6/2/2020 On-site well in perched water zone. Grab sampleOld Outfall 4,900 1,400 CAP1Q20-OLDOF-1-24-040320 3/4/2020 On-site outfall. Composite sampleLTW 6,800 2,400 CAP1Q20-LTW-02-022420 2/24/2020 On-site well in Black Creek Aquifer. Grab sampleSample InformationPMPA(ng/L)PEPA(ng/L)• Five samples were initially analyzed by the Table 3 Method– This generated the PMPA and PEPA data shown above• The same (retained) samples were re-analyzed by EPA Method 533– This looks for the presence of PFMOPrA and PFMOBA
Groundwater and Surface Water Samples: PMPA / PFMOPrA328-Mar-2021PFMOPrA(ng/L)Ratio ofPMPA to PFMOPrAPFMOPrA(ng/L)Ratio ofPMPA to PFMOPrATestAmerica Outfall 002 66 < 2.0-- --> 33:1Bladen-1D 450 < 2.0-- --> 230:1PW-06 1,600 7.4--3.8 430:1Old Outfall 4,900 37--26 190:1LTW 6,800 36--21 330:1Lancaster Outfall 002 66 < 1.6 > 41:1-- --Bladen-1D 450 < 1.7 > 270:1-- --PW-06 1,600 3.0 530:1-- --Old Outfall 4,900 25 200:1-- --LTW 6,800 23 300:1-- --LaboratorySample LocationPMPA(ng/L)Uncorrected Corrected for False PositiveExample:‐ the corrected PFMOPrA concentration at PW‐06 was 7.4 ‐ (1,600/440) = 3.8 ng/LThe groundwater and surface water samples contain a very small amount of the linear isomer (190 to 530 times lower than the PMPA concentration)
Groundwater and Surface Water Samples: PEPA / PFMOBA338-Mar-2021LaboratorySample LocationPEPA(ng/L)PFMOBA(ng/L)Ratio ofPEPA to PFMOBATestAmerica Outfall 002 25 < 2.0 > 12:1Bladen-1D 120 < 2.0 > 60:1PW-06 580 < 2.0 > 290:1Old Outfall 1,400 2.9 480:1LTW 2,400 5.2 460:1Lancaster Outfall 002 25 < 1.6 > 16:1Bladen-1D 120 < 1.7 > 71:1PW-06 580 < 1.8 > 320:1Old Outfall 1,400 < 1.9 > 740:1LTW 2,400 2.3 1,000:1The groundwater and surface water samples contain a very small amount of the linear isomer (460 to 1,000 times lower than the PEPA concentration)
34Re-analysis of Residential Drinking Water Samples by EPA Method 537.1 Mod(work conducted by GEL Laboratories)8-Mar-2021
Original Analysis of Residential Drinking Water Samples by EPA Method 537.1 Mod35‐‐ PMPA and PEPA were not reportedConcentrations in ng/L8-Mar-2021PMPA PFMOPrA PEPA PFMOBA0072‐W1‐092320 i ‐‐ 176 ‐‐ 30.40094‐W1‐091620 i ‐‐ 375 ‐‐ 84.10147‐W1‐120920‐RAW i ‐‐ 85.2 ‐‐ 55.40161‐W1‐120920 i ‐‐ 9.76 ‐‐ 1.190178‐W1‐100720 i ‐‐ 71.2 ‐‐ 14.60345‐W1‐091620 i ‐‐ 38.2 ‐‐ 2.340347‐W1‐092320 i ‐‐ 11.8 ‐‐ 1.280348‐W1‐092320 i ‐‐ 448 ‐‐ 75.70350‐W1‐100720 i ‐‐ 24.5 ‐‐ 2.010351‐W1‐100720 i ‐‐ 16.0 ‐‐ 2.190353‐W2‐100720 i ‐‐ 7.00 ‐‐ 1.170354‐W1‐100720 i ‐‐ 28.1 ‐‐ 6.000355‐W1‐102120 i ‐‐ 28.0 ‐‐ 7.260357‐W1‐102120‐RAW i ‐‐ 1,140 ‐‐ 3280358‐W1‐102120‐RAW i ‐‐ 1,120 ‐‐ 3030362‐W1‐110420 i ‐‐ 5.17 ‐‐ 1.290363‐W1‐110420 i ‐‐ 17.3 ‐‐ 1.330365‐W1‐120920 i ‐‐ 11.2 ‐‐ 1.930368‐W1‐121720‐TR i ‐‐ 6.95 ‐‐ 1.180371‐W1‐121720 i ‐‐ 8.58 ‐‐ 1.46Field Sample IDOriginal Analysis Original analysis
Original Analysis of Residential Drinking Water Samples by EPA Method 537.1 Mod368-Mar-2021
Original Analysis of Residential Drinking Water Samples by GEL Laboratories378-Mar-2021PMPA 229 → 185 229 → 85 185 → 119 185 → 85 185 → 69PFMOPrA -- 229 → 85 -- -- --PEPA 279 → 235 -- 235 → 135 235 → 119 235 → 69PFMOBA -- 279 → 85 -- -- --AnalyteMass Transitions (m/z)Precursor Ion Transitions Product Ion Transitions
Re- Analysis of Residential Drinking Water Samples by EPA Method 537.1 Mod388-Mar-2021PMPA PFMOPrA PMPA PFMOPrA PEPA PFMOBA PEPA PFMOBA0072‐W1‐092320 i ‐‐ 176 207 0.306 ‐‐ 30.4 39.4 /0094‐W1‐091620 i ‐‐ 375 350 0.323 ‐‐ 84.1 72.2 /0147‐W1‐120920‐RAW i ‐‐ 85.2 226 0.460 ‐‐ 55.4 59.9 /0161‐W1‐120920 i ‐‐ 9.76 9.66 / ‐‐ 1.19 0.653 /0178‐W1‐100720 i ‐‐ 71.2 92.1 / ‐‐ 14.6 14.0 /0345‐W1‐091620 i ‐‐ 38.2 51.0 / ‐‐ 2.34 1.69 /0347‐W1‐092320 i ‐‐ 11.8 15.9 / ‐‐ 1.28 1.08 /0348‐W1‐092320 i ‐‐ 448 460 0.475 ‐‐ 75.7 111 /0350‐W1‐100720 i ‐‐ 24.5 44.4 / ‐‐ 2.01 1.99 /0351‐W1‐100720 i ‐‐ 16.0 20.1 / ‐‐ 2.19 1.91 /0353‐W2‐100720 i ‐‐ 7.00 5.07 / ‐‐ 1.17 0.730 /0354‐W1‐100720 i ‐‐ 28.1 49.3 / ‐‐ 6.00 5.71 /0355‐W1‐102120 i ‐‐ 28.0 30.5 / ‐‐ 7.26 8.42 /0357‐W1‐102120‐RAW i ‐‐ 1,140 1,080 2.78 ‐‐ 328 355 0.4660358‐W1‐102120‐RAW i ‐‐ 1,120 969 2.36 ‐‐ 303 301 /0362‐W1‐110420 i ‐‐ 5.17 1.62 / ‐‐ 1.29 nd /0363‐W1‐110420 i ‐‐ 17.3 20.7 / ‐‐ 1.33 nd /0365‐W1‐120920 i ‐‐ 11.2 18.8 / ‐‐ 1.93 2.08 /0368‐W1‐121720‐TR i ‐‐ 6.95 10.5 / ‐‐ 1.18 0.415 /0371‐W1‐121720 i ‐‐ 8.58 14.0 / ‐‐ 1.46 1.58 /Field Sample IDOriginal Analysis Re‐analysis Original analysis Re‐analysisRatio of PMPA:PFMOPrA is 388:1 and 411:1This may be a false positive or it may be a small, real concentration‐‐ PMPA and PEPA were not reported/   PFMOPrA and PFMOBA were reported as non‐detectConcentrations in ng/L
39Summary8-Mar-2021
Key Messages•Isomers– Branched: PMPA & PEPA Chemours chemistry– Linear: PFMOPrA & PFMOBAnot Chemours chemistry• PMPA and PEPA can be analytically separated from the corresponding linear isomers– Standard analytical methods may show a small false positive response for PFMOPrA if a large amount of PMPA is present• Concentration of linear isomers is 190 to 1,000 times lower than corresponding branched isomers in groundwater, surface water and drinking water samples• Analysis of branched isomers only is appropriate for samples related to the Facility40