1. Navigating the Challenges for the Analysis of PFAS in Environmental Matrices to Meet TRRP Requirements
Charles Neslund, Technical Director
TCEQ Environmental Trade Fair, May 16-17, 2017
Providing comprehensive scientific resources to environmental clients worldwide.

2. Polyfluorinated Compounds
Polyfluorinated Alkyl Substances (PFAS) are a class of compounds that have been in use since the late 1940’s, early 1950’s.
PFAS consists of both perfluorinated and polyfluorinated compounds
Perfluorinated – all carbons in the chain are fully bonded to fluorine
Polyfluorinated – not all carbons in the chain are only bonded to fluorine 2 2

3. Polyfluorinated Compounds
PFAS compounds have been used in many applications. They have been used as additives in fluoropolymer production and as surfactants for numerous consumer applications;
Stain resistant coatings for furniture and carpeting
Coatings for fast food wrappers and boxes
Breathable waterproof fabrics
Insecticides
Lubricants
Chromium Plating (mist suppression) 3 3

4. Polyfluorinated Compounds
PFASs were also used in Aqueous Film Forming Foams (AFFF). Developed by 3M and US Navy in the 1960’s. The low surface tension and positive spreading coefficient enabled film formation on top of lighter, less dense fuels.
AFFF is a complex, proprietary mix that has been used in large volumes for decades;
- Military Oil and Gas Industry
- Airports - Chemical Manufacturing
- Fire Training Installations 4 4

5. Polyfluorinated Compounds
From mid-60’s to 1976, 3M sole source supplier of AFFF
Ansul and National Foam became suppliers in 1976
Since 1994, Angus, Chemguard
and Fire Service Plus
Reality is multiple AFFFs
used at most sites 5 5

6. Polyfluorinated Compounds
However, out of these chemistries there are two compounds that have received the most attention;
PFOA - was used as a surfactant in the manufacture of fluoropolymers – DuPont
PFOS - was the principle component in Scotchgard and AFFF manufactured by 3M – manufacture by 3M has been discontinued since 2002 6 6

7. PFAS Perfluorooctanoic acid (also known as PFOA) MW = 414 amu
BP = °C
Density = 1.8 grams/ml 7 7

8. PFAS Perfluorooctane sulfonic acid (also known as PFOS) MW = 500 amu
BP = 133 °C at 6 torr 8 8

9. PFAS
The fluorine substitution gives this class of compounds unique characteristics
Contain a hydrophobic, fully fluorinated carbon chain
Also contains a hydrophilic functional group
Acids have low pKa’s and therefore at environmental pHs are soluble to moderately water soluble 9 9

10. Polyfluorinated Compounds
There are several chemistries that are being looked at;
perfluorinated carboxylic acids
perfluorinated sulfonic acids/sulfonates
polyfluorinated telomer sulfonates
perfluorinated sulfonamides
fluorotelomer alcohols 10 10

11. Polyfluorinated Compounds
Perfluorobutanoic acid Perfluorobutanesulfonate
Perfluoropentanoic acid Perfluorohexansulfonate
Perfluorohexanoic acid Perfluoroheptanesulfonate
Perfluorheptanoic acid Perfluorooctanesulfonate
Perfluorooctanoic acid Perfluorodecanesulfonate
Perfluorononanoic acid Perfluorooctanesulfonomide
Perfluorodecanoic acid Methylperfluoro-1-octanesulfonamide
Perfluoroundecanoic acid Ethylperfluoro-1-octanesulfonamide
Perfluorododecanoic acid 4:2 Fluorotelomer sulfonate
Perfluorotridecanoic acid 6:2 Fluorotelomer sulfonate
Perfluorotetradecanoic acid 8:2 Fluorotelomer sulfonate
Perfluorohexadecanoic acid 10:2 Fluorotelomer sulfonate
N-methylperfluoro-1-octanesulfonamidoacetic acid
N-ethylperfluoro-1-octanesulfonamidoacetic acid
2-(N-methylperfluoro-1-octanesulfamido)-ethanol
2-(N-ethylperfluoro-1-octanesulfamido)-ethanol 11 11

12. Polyfluorinated Compounds
PFASs are generally chemically and biologically stable. Resist typical environmental degradation processes
PFASs bioaccumulate and by some estimates are present in blood serum of up to 98% of wildlife
PFOS added to Stockholm Convention list of Persistent Organic Pollutants
Growing library of toxicological and eco- toxicological studies so impacts are becoming better understood. Reference dose values for many compounds still an issue.

13. Advisory Limits New Jersey preliminary health based guidance**
EPA Office of Water established Health Advisory Levels*
PFOS = 0.07 ug/l PFOA = 0.07 ug/l
Minnesota one of few states with any regulatory action limits
PFOS = 0.3 ug/l PFBS = 7 ug/l
PFOA = 0.3 ug/l PFBA = 7 ug/l
New Jersey preliminary health based guidance**
PFOS = 0.2 ug/l PFNA = 0.01 ug/l
PFOA = 0.04 ug/l (** ug/l)
Vermont Groundwater Enforcement Standard
PFOS = 0.02 ug/l PFOA = 0.02 ug/l
EPA Region 4 levels in soils
PFOS = 6 mg/kg PFOA = 16 mg/kg 13 13

14. Advisory Limits - Update
* The U.S. Environmental Protection Agency (EPA) is issuing a lifetime drinking water Health Advisory (HA) for PFOA of 0.07 micrograms per liter (μg/L) based on a reference dose (RfD) derived from a developmental toxicity study in mice; the critical effects included reduced ossification in proximal phalanges and accelerated puberty in male pups following exposure during gestation and lactation.
EPA Document Number: 822-R May 2016
The U.S. Environmental Protection Agency (EPA) is issuing a lifetime drinking water health advisory (HA) for PFOS of 0.07 micrograms per liter (μg/L) based on a reference dose (RfD) derived from a developmental toxicity study in rats; the critical effect was decreased pup body weight following exposure during gestation and lactation.
EPA Document Number: 822-R May 2016 14 14

15. Tier 1 Groundwater PCLs Compound CAS # Conc ng/l
Perfluorooctanoic sulfonic acid
560
Perfluoroundecanoic acid
290
Perfluoropentanoic acid 93
Perfluorohexanoic acid
Perfluorododecanoic acid
Perfluorooctanoic acid
Perfluorodecanoic acid
370
Perfluorodecane sulfonic acid
Perfluorohexane sulfonic acid
Perfluorobutyric acid
71,000
Perfluorobutane sulfonic acid
34,000
Perfluoroheptanoic acid
Perfluorononanoic acid
Perfluorotetradecanoic acid
Perfluorotridecanoic acid
Perfluorooctane sulfonamide 15 15

16. Analytical Methodology
There is only one EPA “sanctioned” method for the analysis of perfluorinated compounds – EPA Method 537, Version 1.1
Drinking water method – prescriptive list of compounds
Uses LC/MS/MS which is the analytical technique of choice
Has some limitations in the range of compounds that can be accommodated 16 16

17. Analytical Methodology
ISO Method 25101: 2009 often referenced, more amenable to surface water and wastewater
ASTM Methods D addresses water and ASTM D addresses sludges and soils but have not been subject to an EPA validation
No established method for soils, so often certify to lab SOP 17 17

18. Analytical Methodology
These methods are typically fit for the stated purpose, but may fall short as list of compounds and matrices increases.
In general, water methods use solid phase extraction (SPE) for the removal of PFASs from aqueous matrix
Soil methods involve extraction with solvent and/or water mix 18 18

19. Analytical Methodology
EPA Method 537 uses an SDVB solid phase extraction cartridge, which is adequate for the compounds listed. Falls short with additional compounds like the C4 and C5 acids.
EPA 537 uses 3 surrogate compounds and 3 internal standards.
Calibration is a typical internal standard calibration, which can be impacted by ion suppression observed with some matrices 19 19

20. UCMR3 Unregulated Contaminant Monitoring Rule
Perfluorinated Compounds (PFCs): EPA Method 537 included as UCMR3 List 1 Contaminants;
Compound MRL ug/l
Perfluorooctanesulfonic acid
Perfluoroctanoic acid
Perfluorononanoic acid
Perfluorohexanesulfonic acid
Perfluoroheptanoic acid
Perfluorobutanesulfonic acid 20 20

21. UCMR3 Compounds are selected from the Contaminant Candidate List
Measures contaminants with no health standards under the Safe Drinking Water Act
Used to determine whether or not to regulate. Typically requires > 30-40% detects
Focused on large water supplies (serving >10,000 people)
Approximately 4% of UCMR3 water samples had PFAS detections above MRLs 21 21

22. Analytical Methodology
ASTM D avoids extraction by using direct injection
Use 9 isotopically labeled compounds as surrogates
Uses external standard calibration
Covers a much broader list of PFAS compounds – up to 21
Reporting limits in the 5 ng/l to 25 ng/l range for most compounds 22 22

23. For Comparison… 23 Analyte Acronym Water Reporting Limits LOQ (ng/L)
Soil Reporting Limits LOQ (ng/g)
Perfluorohexanoic acid
PFHxA 2
0.4
Perfluoroheptanoic acid
PFHpA
0.6
Perfluorooctanoic acid
PFOA
Perfluorononanoic acid
PFNA
Perfluorodecanoic acid
PFDA
Perfluoroundecanoic acid
PFUnDA 3
Perfluorododecanoic acid
PFDoA
Perfluorotridecanoic acid
PFTrDA
Perfluorotetradecanoic acid
PFTeDA
Perfluorobutanesulfonate
PFBS
Perfluorohexanesulfonate
PFHxS
Perfluoro-octanesulfonate
PFOS 6
0.9
8:2 fluorotelomersulfonate
8:2 FtS 10 23 23

24. Analytical Methodology
For our applications, we are tasked with a broader list of compounds and a wider range of matrices
- Water/wastewater
- soil/sediment
- tissue
Use of weak anion exchange for extraction/clean-up
Incorporated the use of 18 isotopically labeled compounds as surrogates and isotope dilution quantitation 24 24

25. Instrumental Analysis

26. Analytical Methodology
Added in the use of several injection standards for monitoring and comparing instrument vs extraction performance
Target list of compounds increased to 27 “native” covered by 18 labeled compounds
As manufacturers provide more labeled analogs, will be a complete isotope dilution technique 26 26

27. Instrumental Analysis

28. Instrumental Analysis

29. Recent Updates
EPA is releasing a document titled, “Technical Advisory-Laboratory Analysis of Drinking Water Samples for Perfluorooctanoic Acid (PFOA) Using EPA method 537 Rev 1.1.” This advisory describes a processes for laboratories to measure PFOA in a more comprehensive way. The improved technique allows laboratories to more consistently account for isomeric forms of PFOA (linear, the dominant form and branch-chained, the less common form) in the absence of a quantitative analytical standard that includes the various isomers. The approach described in the advisory is more inclusive and more protective.  EPA therefore recommends that laboratories use the technique in future analysis.

30. Analytical Methodology
In response to this guidance document acquired technical grade standards of PFOS, PFOA and PFHxS.
Technical grade standards run with initial calibrations as a qualitative indication of retention of branched isomers.
Branched summed with linear peak for calculation of PFAS content. 30 30

31. Analytical Methodology
Total Ion Chromatogram of Technical Grade Standard 31 31

32. Analytical Methodology32 32

33. Future
At North American SETAC meeting in Orlando, FL in November of 2016, EPA indicated that they expect to release two draft methods for the analysis of PFAS compounds in non-potable water and soils/sediments by March of 2017.
Update given in March that the process has been delayed and now estimate to be end of May 2017. 33 33

34. Future – TOP Analysis TOP – Total Oxidizable Precursors
Based on paper authored by Erika Houtz and David Sedlak (ES&T, 2012, 46, )
Concept is to analyze a sample for perfluorinated acids and precursors (such as telomer sulfonates). Then subject a second aliquot of the sample to relatively harsh oxidative conditions. Analyze the oxidized sample for the same perfluorinated acids and precursors. Expect to see;
a. Reduction or elimination of the precursors
b. Increase in concentrations of perfluorinated acids 34 34

35. Summary
The emergence of contaminants like PFAS have increased the need and use of LC/MS/MS in the environmental lab
What “started out” as an analysis for PFOA and PFOS has rapidly grown to a more expanded list
As the list of analytes and matrices has expanded it has required labs to modify existing methodologies to achieve desired quality and performance
Delivery of the anticipated EPA methods could bring about the needed consistency 35 35

36. Questions