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Region 5 CRL Methods for the Analysis of Polyfluorinated Compounds (PFCs) Using a Quick

Sample Extraction/Preparation Followed by UPLC/MS/MS Analysis

Mention of Vendor Names Does Not Constitute Product Endorsement

Lawrence B. Zintek, Danielle Kleinmaier, Dennis J. Wesolowski, Solidea Bonina# and Carolyn Acheson*

US EPA Region 5 Chicago Regional Laboratory (CRL)#Pegasus Technical Services

*US EPA ORD/NRMRL, Cincinnati, OH.

http://www.epa.gov/

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Disclaimer

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States government.

The views and opinions of author expressed herein do not necessarily state or reflect those of the United States government or United States Environmental Protection Agency and shall not be used for advertising or product endorsement purposes.

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Disclaimer Continued

This work was sponsored by an agency of the United States government. Neither the United States government nor US EPA Region 5 Chicago Regional Laboratory, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness,or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.

Topics

• PFC Workgroup• Brief PFC Background• EPA Method 537- Drinking Water• CRL PFC Methods • Holding Time Study• Contamination • Sample Collection• Holding Time/Sample Requirements• Analytical Issues Observed from

Review of PFAS Site QAPPs• Review Data generated by other methods/labs• Conclusion/Ongoing Work

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EPA PFC Workgroup

• Purpose: Sampling Protocol and analytical method development for solids and water other than drinking water.

• Workgroup Co-Leads– OLEM/OSRTI, Region 3, ORD/SSWR

• Program Offices– OLEM/OEM, OLEM/OSRTI, OW/OS&T, OW/OGWDW,

OLEM/OCRC, NEIC, OCIR/RO, OPP/BEAD/ACB

• Regional Offices– 1,2,3,4,5,6,9,10

• Office of Research and Development– NRMRL, NERL, NHEERL, NCEA

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Brief PFC Background

• PFOA

• PFOS

• 6:2 FTS

• PFOSA (FOSA)

• N-EtFOSAA6

PFOA/PFOS Drinking Water Health Advisory- 70 ng/L Combined

Method 537 Quantitation• One SRM transition

– Weak approach for non-drinking water samples, no confirmatory transition and no ion ratios

– Example for PFOS

7Time8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

82316lev4 14: MRM of 3 Channels ES- 498.9 > 79.9 (PFOS79.7)

1.51e5

8.59

8.46

8.40 8.40

Time8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

8231608004_18 14: MRM of 3 Channels ES- 498.9 > 79.9 (PFOS79.7)

1.52e5

8.60

8.40

8.38

8.24

8.45

8.62

Calibration Standard Real Sample

Region 5 CRL PFC SOP• Two SRM transitions or MRM

– Stronger approach for non-drinking water samples, confirmatory transition and ion ratios

– Example for PFOS, same samples

8Time

8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

82316lev4 14: MRM of 3 Channels ES- 498.9 > 98.9 (PFOS98.7)

1.06e5

8.59

8.458.47

82316lev4 14: MRM of 3 Channels ES- 498.9 > 79.9 (PFOS79.7)

1.51e5

8.59

8.46

8.40 8.40

Time8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

8.05 8.10 8.15 8.20 8.25 8.30 8.35 8.40 8.45 8.50 8.55 8.60 8.65 8.70 8.75 8.80 8.85

%

0

100

8231608004_18 14: MRM of 3 Channels ES- 498.9 > 98.9 (PFOS98.7)

1.36e5

8.60

8.40

8.39

8.23

8.45

8.46

8.47

8.62

8.64

8231608004_18 14: MRM of 3 Channels ES- 498.9 > 79.9 (PFOS79.7)

1.52e5

8.60

8.40

8.38

8.24

8.45

8.62

Calibration Standard Ion Ratio-1.41 Real Sample Ion Ratio-1.35

4.3% Ion Ratio Difference (Within Tolerance)

EPA Method 537

• Drinking Water Only

• 14 Analytes, all in OSRTI List

– PFOS, PFOA, N-EtFOSAA, N-MeFOSAA, PFBS, PFDA, PFDoA, PFHpA, PFHxS, PFHxA, PFNA, PFTreA, PFTriA, PFUnA.

• 3 Surrogates

– MPFHxA, MPFDA, MN-EtFOSAA

• 3 Internal Standards

– 13C-PFOA, 13C-PFOS, d3-N-MeFOSAA9

Method 537 Quantitation/Surrogates• Internal standard quantitation (Q)

– Weak approach for non-drinking water samples, may have a matrix interference that affects the internal standard resulting in bias results for anything quantitated against it.

• Surrogates (S)– Compare target analyte recovery to the surrogates.

10Time

3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 10.50

%

0

100

020817leva7 24: MRM of 2 Channels ES- 713 > 669 (PFTreA669)

9.88e4

10.67

MNEtFOSAA, S

MPFHxA, S

MNMeFOSAA, IS

MPFOS, ISMNEtFOSSA, S

MPFOA, IS

Q

Q, QS S

S

Why not use EPA Method 537 for Matrices other than Drinking Water?

• Method 537 is a drinking water method!• Not adaptable to other matrices• Only one SRM transition

– Makes quantitation difficult in dirtier matrices– Less confirmatory

• Require Solid Phase Extraction– Won’t work for all analytes of interest in one analysis– Pre-filter samples with particulates (Bias low results)

• Limited number of surrogates to mimic the entire analyte mix• Internal Standard

– May make the data worse

• Blow down to dryness– Lose volatile PFCs

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CRL PFC Methods

• 24 Analytes of Interest to OSRTI• External Standard Quantitation

– Every compound independent of each other

• 2 SRM transitions (If available)– PFBA, PFPeA and PFOSA only one SRM

• Ion Ratios between the 2 SRM transitions required• 14 Surrogates (19 available now)• Easy sample preparation, sample manipulations to a

minimum.• Basis- ASTM D7979 and D7968 • Heavily single lab validated on multiple matrices

– Data available

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Region 5 CRL PFC SOP Reporting Limits/Surrogates

AnalyteReporting Limit (Water) Reporting Limit (Soil)

Surrogate

(ng/L) (ng/Kg)

PFTreA 10 25 New

PFTriA 10 25

PFDoA 10 25 X

PFUnA 10 25 X

PFDA 10 25 X

PFDS 10 25

PFOS 10 50 X

PFNA 10 25 X

PFNS 10 25

PFOA 10 25 X

PFHpS 10 25

PFHxS 10 25 X

PFHpA 10 25 New

PFHxA 10 50 X

PFBS 10 25 New

PFPeS 10 25

PFPeA 50 125 New

PFBA 50 125 X

FOSA 10 25 New

4:2 FTS 10 25 X

6:2 FTS 10 25 X

8:2 FTS 10 25 X

NEtFOSAA 10 25 X

NMeFOSAA 10 25 X

CRL PFC SOP Water Sample Preparation

• 5 mL water sample in Polypropylene Tube

• Add “Spikes”

• Add 5 mL MeOH

• Shake- 30 seconds

• Filter through Polypropylene Filter Unit

• Add 10 mL acetic acid

• Analyze

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CRL PFC SOP Sludge Sample Preparation

• 5 mL Sludge sample in PP tube

• Add “Spikes”

• Add 5 mL MeOH

• Add 20 mL NH4OH, Shake, check if basic, pH 9-10.

• Mix for 2 minutes

• Decant the liquid and filter through Polypropylene Filter Unit

• Add 50 mL acetic acid

• Analyze15

CRL PFC SOP Soil/Biosolid Sample Preparation

• 2 gram sample (sub-sample)

• Add “Spikes”

• 10 ml of methanol:water (50:50) -shake/vortex for ~ 2 minutes.

• Add 20 mL NH4OH, shake/vortex for ~ 2 minutes, check if basic, pH 9-10.

• Tumble for 1 hr

• Centrifuge

• Decant the liquid and Filter through Polypropylene Filter Unit

• Add 50 mL acetic acid

• Analyze

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NC Sludge Sample

Before Extraction

NC Sludge Sample

After Extraction

Sludge samples

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Matrices Used to do Single Lab Validationusing CRL PFC SOP for Water

• Reagent Water

• Chicago River Water

• Ground Water: Silurian-Dolomite Aquifer

• Sewage Treatment Plant I (STP) Effluent

• STP I Influent

• STP II (Effluent with supplemental sewage)

• STP III (Effluent with supplemental sewage)

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• Ottawa Sand

• Four ASTM Soils

– Sand

– Lean Clay

– Fat Clay

– Silt

Matrices Used to do Single Lab Validationusing CRL PFC SOP for Soil

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MPFBA (Surrogate) Recovery Data in Water Samples Over Last 19 Months

• Example of a Control Chart displaying recoveries for data collected with CRL Water Method

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CRL PFC Water SOP Precision and Accuracy

• Includes target and surrogate analytes (ASTM D7979).

• Samples- 101 Blanks, 97 MRLs, 102 BSs, 189 MSs and 416 samples.

• Accuracy

– Average Recovery: 99.2%

• Precision (Standard Deviation)

– Average Precision: ±6.08%

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CRL PFC Soil SOP Precision and Accuracy

• Includes target and surrogate analytes (ASTM D7968).

• Samples- 37 Blanks, 31 MRLs, 42 BSs, 26 MSs and 138 samples.

• Accuracy

– Average Recovery: 90.3%

• Precision (Standard Deviation)

– Average Precision: ±15.8%

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Holding Time Study in POTW Influent

• Compare concentrations sampling the same spiked bottles over 27 days (Aliquot, not using the entire sample) – Amber Glass

– Polypropylene

– HDPE

• Losses over time with each sampling container

• Drastic differences between reagent water and POTW influent recovery results.

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Holding Time- Polypropylene tubes (POTW Influent)

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Holding Time- Amber Glass Bottles(POTW Influent)

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Holding Time- HDPE Bottles(POTW Influent)

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Holding Time Study in POTW Influent using Entire Sample

• Spiked into POTW influent and monitored.

• Polypropylene- Eighteen separate spiked samples prepared to use the entire sample. Small sample size – 5 mL.

• Pyrex Glass- Twelve separate spiked samples prepared to use the entire sample. Small sample size – 5 mL.

• Corroborates that the entire sample must be used.

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Whole Sample Influent(Polypropylene tubes- 31 days)

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Whole Sample Influent(Compare Glass to Polypropylene)

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Contamination (Be cautious!)

• Teflon® Containing Materials

• Waterproof Field Books

• Plastic Clipboards, binders, or spiral hard cover books

• Post-it Notes

• Chemical (blue) ice packs

• Tyvek®

• Glass Pipettes-PFC contaminated- PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA

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Contamination (Be cautious!)

• New clothing or water resistant, waterproof, or stain-treated clothing, clothing containing Gore-Tex™

• LDPE containers

• Decon 90

• Water from an on-site well

• Aluminum Foil

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Sample Collection

• Collect a 5.0 mL sample, grab would be best, in a graduated 15 mL polypropylene BD Falcon tube in the field so that the whole sample is processed in the lab (NO ALIQUOTING).

• In order to have accurate volumes, the weight of the 15 mL polypropylene BD Falcon tube may be taken before and after sampling in order to get an exact volume. The density of water is assumed to be 1.0 g/mL unless the exact density of the water sample is known, then that conversion should be used.

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Holding time/Sample Requirements

• 28 Days

• Required to collect a separate sample for each QC Sample (Co-located). Collecting in one container in the field and transferring to other containers may lead to low biased results.

• Have to prepare and use the entire sample.

• Take a couple extra samples in case re-extract required.

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Analytical Issues Observed from Review of PFAS Site QAPPs: Environmental Water

• Matrix – environmental water (groundwater, surface water, wastewater from treatment)

• Method – options

– No EPA approved method – cross agency workgroup is working on methods

– ASTM D7979

– Common for labs to cite “Modified Method 537”. This term is meaningless.

– Other methods may be acceptable

• Ask for the SOP and performance data

• Compare to level of information in Method 537 or ASTM method

• Is QC similar to other methods?

• Is aliquot or whole sample used?

Analytical Issues Observed from Review of PFAS Site QAPPs: Solids

• Matrix – solids (soil and sediment)

• Method – options

• No EPA approved method – cross agency workgroup is working on methods

• ASTM D7968

• Common for labs to cite “Modified Method 537”. Even more meaningless since solid matrices.

• Other methods may be acceptable

• Ask for the SOP and performance data

• Compare to level of information in Method 537 or ASTM method

• Is QC similar to other methods?

• Is sample dried before extraction?

Analytical Issues Observed from Review of PFAS Site QAPPs: Common and Outstanding Issues

• Unwilling to share complete SOPs– Label their methods as confidential business information – Share redacted SOPs– Without seeing SOPs, not possible to have confidence in data.

• Do not supply performance data– Performance Data Benchmarks to look for

• Method 537 - precision and accuracy data for 4 matrices, 7 replicates • ASTM D7968 - precision and accuracy data for at least 5 matrices, 6 replicates

– Agency should expect similar level of data

• DoD accreditation– Not clear what data are required to obtain accreditation– Not clear if EPA was consulted on accreditation criteria – Critical to thoroughly review QAPP to determine if SOPs used are

sufficient

If You Review Data Generated by Other Methods

• Previously Published methods on PFCs– EPA Method 537, ASTM D7979 or D7968, Journal?– Are they really following the methods they cite?

• Using the entire sample?• Many sample manipulations involved?• Pre-filter?• Complicated Sample Preparation?• Batch QC-Surrogates, duplicates, matrix spikes, reporting limit

checks?• Ongoing Method Performance in Real Matrices?• Quantitation?

– SRM or MRM, Ion Ratios? – Isotope dilution, are they getting single digit, or lower, recoveries of

their isotopes and correcting the data? (Turn a bad method into a so-so method! Reference- Phrase from EPA/OW/OS&T)

– Equilibration time of the isotopes in the sample?– Are the isotopes at a similar concentration as their reporting range?

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Conclusion/Ongoing work

• Use Entire Sample

• Quick and robust analyses

• Multi-lab validating methods

– Internal EPA (now)

– External

• Plan is to place in SW-846

• Updated ASTM D7979 (Waters/sludges, not drinking water!) and D7968 (Soils).

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More Information

• Contact: Dennis Wesolowski, US EPA Region 5 Chicago Regional Lab Director– 312-353-9084

• Contact: Larry Zintek, Chemist – 312-886-2925

• Contact: Robert Thompson, Chemist and Sample Coordinator – 312-353-9078

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