ASTM D7968-14
(Test Method)Standard Test Method for Determination of Perfluorinated Compounds in Soil by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS)
Standard Test Method for Determination of Perfluorinated Compounds in Soil by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS)
SIGNIFICANCE AND USE
5.1 This test method has been developed by the US EPA Region 5 Chicago Regional Laboratory (CRL).
5.2 PFCs are widely used in various industrial and commercial products; they are persistent, bio-accumulative, and ubiquitous in the environment. PFCs have been reported to exhibit developmental toxicity, hepatotoxicity, immunotoxicity, and hormone disturbance. A draft Toxicological Profile for Perfluoroalkyls from the U.S. Department of Health and Human Services is available.7 PFCs have been detected in soils, sludges, surface and drinking waters. Hence, there is a need for quick, easy, and robust method to determine these compounds at trace levels in various soil matrices for understanding of the sources and pathways of exposure.
5.3 This method has been used to determine selected perfluorinated compounds in sand (Table 4) and four ASTM reference soils (Table 5).
SCOPE
1.1 This procedure covers the determination of selected perfluorinated compounds (PFCs) in a soil matrix using solvent extraction, filtration, followed by liquid chromatography (LC) and detection with tandem mass spectrometry (MS/MS). These analytes are qualitatively and quantitatively determined by this method. This method adheres to multiple reaction monitoring (MRM) mass spectrometry. This procedure utilizes a quick extraction and is not intended to generate an exhaustive accounting of the content of PFCs in difficult soil matrices. An exhaustive extraction procedure for polyfluoralkyl substances, such as published by Washington et al.2, for difficult matrices should be considered when analyzing PFCs.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 The Method of Detection Limit3 and Reporting Range4 for the target analytes are listed in Table 1. (A) Abbreviations are defined in 3.2.
1.3.1 The reporting limit in this test method is the minimum value below which data are documented as non-detects. Analyte detections between the method detection limit and the reporting limit are estimated concentrations and are not reported following this test method. In most cases, the reporting limit is calculated from the concentration of the Level 1 calibration standard as shown in Table 2 for the perfluorinated compounds after taking into account a 2 g sample weight and a final extract volume of 10 mL, 50 % water/50 % MeOH with 0.1 % acetic acid. The final extract volume is assumed to be 10 mL because 10 mL of 50 % water/50 % MeOH with 0.1 % acetic acid was added to each soil sample and only the liquid layer after extraction is filtered leaving the solid and any residual solvent behind. It is raised above the Level 1 calibration concentration for PFOS, PFHxA, FHEA, and FOEA, these compounds can be identified at the Level 1 concentration but the standard deviation among replicates at this lower spike level resulted in a higher reporting limit.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D7968 −14
Standard Test Method for
Determination of Perfluorinated Compounds in Soil by
Liquid Chromatography Tandem Mass Spectrometry (LC/
MS/MS)
This standard is issued under the fixed designation D7968; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope compounds after taking into account a 2 g sample weight and
afinalextractvolumeof10mL,50%water/50%MeOHwith
1.1 This procedure covers the determination of selected
0.1%aceticacid.Thefinalextractvolumeisassumedtobe10
perfluorinatedcompounds(PFCs)inasoilmatrixusingsolvent
mL because 10 mL of 50% water/50% MeOH with 0.1%
extraction, filtration, followed by liquid chromatography (LC)
acetic acid was added to each soil sample and only the liquid
anddetectionwithtandemmassspectrometry(MS/MS).These
layer after extraction is filtered leaving the solid and any
analytesarequalitativelyandquantitativelydeterminedbythis
residual solvent behind. It is raised above the Level 1 calibra-
method. This method adheres to multiple reaction monitoring
tionconcentrationforPFOS,PFHxA,FHEA,andFOEA,these
(MRM) mass spectrometry. This procedure utilizes a quick
compounds can be identified at the Level 1 concentration but
extraction and is not intended to generate an exhaustive
the standard deviation among replicates at this lower spike
accounting of the content of PFCs in difficult soil matrices.An
level resulted in a higher reporting limit.
exhaustive extraction procedure for polyfluoralkyl substances,
1.4 This standard does not purport to address all of the
such as published by Washington et al. , for difficult matrices
safety concerns, if any, associated with its use. It is the
should be considered when analyzing PFCs.
responsibility of the user of this standard to establish appro-
1.2 Units—The values stated in SI units are to be regarded
priate safety and health practices and determine the applica-
asstandard.Nootherunitsofmeasurementareincludedinthis
bility of regulatory limitations prior to use.
standard.
3 4
2. Referenced Documents
1.3 The Method of Detection Limit and Reporting Range
for the target analytes are listed in Table 1.
2.1 ASTM Standards:
1.3.1 Thereportinglimitinthistestmethodistheminimum
D653Terminology Relating to Soil, Rock, and Contained
value below which data are documented as non-detects. Ana-
Fluids
lyte detections between the method detection limit and the
D1193Specification for Reagent Water
reporting limit are estimated concentrations and are not re-
D2777Practice for Determination of Precision and Bias of
ported following this test method. In most cases, the reporting
Applicable Test Methods of Committee D19 on Water
limit is calculated from the concentration of the Level 1
D3694Practices for Preparation of Sample Containers and
calibration standard as shown in Table 2 for the perfluorinated
for Preservation of Organic Constituents
D3740Practice for Minimum Requirements for Agencies
Engaged in Testing and/or Inspection of Soil and Rock as
This test method is under the jurisdiction ofASTM Committee D34 on Waste
Used in Engineering Design and Construction
Management and is the direct responsibility of Subcommittee D34.01.06 on
D3856Guide for Management Systems in Laboratories
Analytical Methods.
Engaged in Analysis of Water
Current edition approved Nov. 1, 2014. Published December 2014. DOI:
10.1520/D7968-14. D5681Terminology for Waste and Waste Management
Washington, J. W., Naile, J. E., Jenkins, T. M., and Lynch, D. G., “Character-
D5847Practice for Writing Quality Control Specifications
izing Fluorotelomer and Polyfluoroalkyl Substances in New and Aged
for Standard Test Methods for Water Analysis
Fluorotelomer-Based Polymers for Degradation Studies with GC/MS and LC/MS/
E2554Practice for Estimating and Monitoring the Uncer-
MS,” Environmental Science and Technology, Vol. 48, 2014, pp. 5762–5769.
The MDL is determined following the Code of Federal Regulations, 40 CFR
tainty of Test Results of a Test Method Using Control
Part 136, Appendix B utilizing solvent extraction of soil. Two gram sample of
Chart Techniques
Ottawa Sand was utilized.Adetailed process determining the MDLis explained in
the reference and is beyond the scope of this standard to be explained here.
4 5
Reporting range concentration is calculated from Table 2 concentrations For referenced ASTM standards, visit the ASTM website, www.astm.org, or
assuminga30µLinjectionoftheLevel1calibrationstandardforthePFCs,andthe contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
highest level calibration standard with a 10 mL final extract volume ofa2g soil Standards volume information, refer to the standard’s Document Summary page on
sample. Volume variations will change the reporting limit and ranges. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7968−14
A
TABLE 1 Method Detection Limit and Reporting Range
3.2.13 P&A—Precision and Accuracy
MDL Reporting Limit
Analyte 3.2.14 PFAS—Perfluoroalkylsulfonate
(ng/kg) (ng/kg)
PFTreA 6.76 25–1000
3.2.15 PFBS—perfluorobutylsulfonate
PFTriA 5.26 25–1000
PFDoA 3.56 25–1000 3.2.16 PFHxS—perfluorohexylsulfonate
PFUnA 2.45 25–1000
3.2.17 PFOS—Perfluorooctylsulfonate
PFDA 5.54 25–1000
PFOS 18.83 50–1000
3.2.18 PFecHS—Decaluoro-4-
PFNA 2.82 25–1000
(pentafluoroethyl)cyclohexanesulfonate
PFecHS 2.41 25–1000
PFOA 6.24 25–1000
3.2.19 PFAC—Perfluoroalkyl Carboxylic Acid
PFHxS 7.75 25–1000
PFHpA 5.80 25–1000
3.2.20 PFBA—Perfluorobutanoate
PFHxA 15.44 50–1000
3.2.21 PFPeA—Perfluoropentanoate
PFBS 6.49 25–1000
PFPeA 20.93 125–5000
3.2.22 PFHxA—Perfluorohexanoate
PFBA 22.01 125–5000
FHEA 199.04 600–20 000
3.2.23 PFHpA—Perfluoroheptanoate
FOEA 258.37 750–20 000
FDEA 137.46 500–20 000 3.2.24 PFOA—Perfluorooctanoate
FOUEA 4.85 25–1000
3.2.25 PFNA—Perfluorononanoate
FhpPa 5.09 25–1000
FHUEA 3.50 25–1000
3.2.26 PFDA—Perfluorodecanoate
A
Abbreviations are defined in 3.2.
3.2.27 PFUnA—Perfluoroundecanoate
3.2.28 PFTriA—Perfluorotridecanoate
2.2 Other Documents:
3.2.29 PFTreA—Perfluorotetradecanoate
EPA SW-846Test Methods for Evaluating Solid Waste,
3.2.30 FTAs and FTUAs—Fluorotelomer and Unsaturated
Physical/Chemical Methods
Fluorotelomer Acids
40 CFR Part 136 Appendix BDefinition and Procedure for
3.2.31 FHpPA—3-perfluoropheptyl propanoic acid
the Determination of the Method Detection Limit
3.2.32 FOUEA—2H-perfluoro-2-decenoic acid
3. Terminology
3.2.33 FDEA—2-perfluorodecyl ethanoic acid
3.1 Definitions:
3.2.34 FOEA—2-perfluorooctyl ethanoic acid
3.1.1 reporting limit, RL, n—the minimum concentration
3.2.35 FHUEA—2H-perfluoro-2-octenoic acid
below which data are documented as non-detects.
3.2.36 FHEA—2-perfluorohexyl ethanoic acid
3.1.2 perfluorinated compounds, PFCs, n—in this test
method, eleven perfluoroalkyl carboxylic acids, three 3.2.37 MPFAS—Isotopically labeled Perfluoroalkylsul-
perfluoroalkylsulfonates, Decafluoro-4- fonates
(pentafluoroethyl)cyclohexanesulfonate, and six fluorotelomer
3.2.38 MPFHxS— O -Perfluorohexylsulfonate
acids listed in Table 1 collectively (not including mass labeled
3.2.39 MPFOS— C -Perfluorooctylsulfonate
surrogates).
3.2.40 MPFCA—Isotopically labeled Perfluoroalkylcar-
3.2 Abbreviations:
boxylates
3.2.1 CCC—Continuing Calibration Check
3.2.41 MPFBA— C -Perfluorobutanoate
3.2.2 IC—Initial Calibration
3.2.42 MPFHxA— C -Perfluorohexanoate
3.2.3 ppt—parts per trillion, ng/kg or ng/L
3.2.43 MPFOA— C -Perfluorooctanoate
3.2.4 LC—Liquid Chromatography
3.2.44 MPFNA— C -Perfluorononanoate
3.2.5 LCS/LCSD—Laboratory Control Sample/Laboratory
3.2.45 MPFDA— C -Perfluorodecanoate
Control Sample Duplicate
3.2.46 MPFUnA— C -Perfluoroundecanoate
3.2.6 MDL—Method Detection Limit
3.2.7 MeOH—Methanol 3.2.47 MPFDoA— C -Perfluorodecanoate
-3
3.2.8 mM—millimolar,1×10 moles/L 3.2.48 QA—Quality Assurance
3.2.9 MRM—Multiple Reaction Monitoring
3.2.49 QC—Quality Control
3.2.10 MS/MSD—Matrix Spike/Matrix Spike Duplicate 3.2.50 RL—Reporting Limit
3.2.11 NA—Not available
3.2.51 RLCS—Reporting Limit Check Sample
3.2.12 ND—non-detect
3.2.52 RSD—Relative Standard Deviation
3.2.53 RT—Retention Time
Available from National Technical Information Service (NTIS), U.S. Depart-
3.2.54 SRM—Single Reaction Monitoring
ment of Commerce, 5285 Port Royal Road, Springfield, VA, 22161, http://
www.epa.gov/epawaste/hazard/testmethods/index.htm 3.2.55 SS—Surrogate Standard
D7968−14
TABLE 2 Concentrations of Calibration Standards (ng/L)
Analyte/Surrogate LV1 LV2 LV3 LV4 LV5 LV6 LV7 LV8 LV9
PFPeA, PFBA 25 50 100 200 300 400 500 750 1000
PFTreA, PFTriA, PFDoA, PFUnA, PFDA, PFOS, PFNA, PFHxA, PFHpA, PFBS,
PFechS, PFOA, PFHxS, FOUEA, FHUEA, FHpPA, MPFBS, MPFHxA, MPFUnA, 5 10 20 40 60 80 100 150 200
MPFOA, MPFDA, MPFOS, MPFNA, MPFHxS, MPFBA
FHEA, FOEA, FDEA 100 200 400 800 1200 1600 2000 3000 4000
3.2.56 TC—Target Compound quick, easy, and robust method to determine these compounds
at trace levels in various soil matrices for understanding of the
4. Summary of Test Method
sources and pathways of exposure.
4.1 The operating conditions presented in this test method
5.3 This method has been used to determine selected per-
have been successfully used in the determination of perfluori-
fluorinated compounds in sand (Table 4) and four ASTM
natedcompoundsinsoil;however,thistestmethodisintended
reference soils (Table 5).
to be performance based and alternative operating conditions
can be used to perform this method provided data quality
6. Interferences
objectives are attained.
6.1 All glassware is washed in hot water with detergent and
4.2 For PFC analysis, samples are shipped to the lab on ice
rinsed in hot water followed by distilled water. The glassware
and analyzed within 28 days of collection. A sample (2 g) is
is then dried and heated in an oven at 250°C for 15 to 30
transferredtoapolypropylenetube,spikedwithsurrogates(all
minutes.Allglasswareissubsequentlyrinsedwithmethanolor
samples) and target PFC compounds (laboratory control and
matrix spike samples). The analytes are tumbled for an hour acetonitrile.
with 10 mL of methanol:water (50:50) under basic condition
6.2 All reagents and solvents should be pesticide residue
(pH ~ 9-10 adjusted with ~20 µL ammonium hydroxide). The
purity or higher to minimize interference problems.The use of
samples are centrifuged and the extract, leaving the solid
PFC containing caps should be avoided.
behind, is filtered through a polypropylene filter unit. Acetic
acid (~50 µL) is added to all the filtered samples to adjust the
6.3 Matrix interferences may be caused by contaminants in
pH ~3-4 and then analyzed by LC/MS/MS.
the sample. The extent of matrix interferences can vary
considerably depending on variations in the sample matrices.
4.3 Most of the PFC target compounds are identified by
comparingthesinglereactionmonitoring(SRM)transitionand
6.4 Contaminants have been found in reagents, glassware,
its confirmatory SRM transition if correlated to the known
tubing, glass disposable pipettes, filters, degassers, and other
standard SRM (Table 3) and quantitated utilizing an external
apparatus that release perfluorinated compounds. All of these
calibration. The surrogates and some PFC target analytes
materials and supplies are routinely demonstrated to be free
(PFPeA, PFBA, FOUEA, and FHUEA) only utilize one SRM
from interferences by analyzing laboratory reagent blanks
transition due to a less sensitive or non-existent secondary
under the same conditions as the samples. If found, measures
SRM transition. As an additional quality control measure,
shouldbetakentoremovethecontaminationordatashouldbe
isotopically labeled PFC surrogates (listed in 12.4) recoveries
qualified;backgroundsubtractionofblankcontaminationisnot
are monitored. There is no correction to the data based upon
allowed.
surrogate recoveries. The final report issued for each sample
lists the concentration of PFCs, if detected, or RL, if not
6.5 The Liquid Chromatography system used should
detected, in ng/kg (Dry Weight Basis) and the surrogate
consist, as much as practical, of sample solution or eluent
recoveries.
contacting components free of PFC target analytes of interest.
5. Significance and Use
6.6 Polyethylene LC vial caps or any other target analyte
free vial caps should be used.
5.1 This test method has been developed by the US EPA
Region 5 Chicago Regional Laboratory (CRL).
6.7 Polyethylene disposable pipettes or target analyte free
5.2 PFCsarewidelyusedinvariousindustrialandcommer- pipettes should be used. All disposable pipettes should be
cial products; they are persistent, bio-accumulative, and ubiq-
checked for release of target analytes of interest.
uitous in the environment. PFCs have been reported to exhibit
6.8 DegassersareimportanttocontinuousLCoperationand
developmental toxicity, hepatotoxicity, immunotoxicity, and
most commonly are made of fluorinated polymers. To enable
hormonedisturbance.AdraftToxicologicalProfileforPerfluo-
use,anisolatorcolumnshouldbeplacedafterthedegasserand
roalkyls from the U.S. Department of Health and Human
prior to the sample injection valve to separate the PFCs in the
Services is available. PFCs have been detected in soils,
sample from the PFCs in the LC system.
sludges,surfaceanddrinkingwaters.Hence,thereisaneedfor
7. Apparatus
A draft Toxicological Profile for Perfluroalkyls can be found at http://
www.atsdr.cdc.gov/toxprofiles/tp.asp?id=1117&tid=237 (2014). 7.1 LC/MS/MS System:
D7968−14
TABLE 3 Retention Times, SRM Ions, and Analyte-Specific Mass Spectrometer Parameters
Primary/
Primary/ Retention Times
Chemical Cone (V) Collision (eV) MRM Transition Confirmatory SRM
Confirmatory (min)
Area Ratio
Primary 20 13 712.9→668.9
PFTreA 10.63 7.4
Confirmatory 20 30 712.9→169
Primary 25 12 662.9→618.9
PFTriA 10.17 7.4
Confirmatory 25 28 662.9→169
Primary 10 12 612.9→568.9
PFDoA 9.61 8.2
Confirmatory 10 25 612.9→169
Primary 15 10 562.9→519
PFUnA 9.05 7.2
Confirmatory 15 18 562.9→269
Primary 20 10 512.9→468.9
PFDA 8.45 6.5
Confirmatory 20 16 512.9→219
Primary 10 42 498.9→80.1
PFOS 8.78 1.3
Confirmatory 10 40 498.9→99.1
Primary 20 10 462.9→418.9
PFNA 7.78 4.9
Confirmatory 20 16 462.9→219
Primary 10 25 460.9→381
PFecHS 8.1 2.2
Confirmatory 10 25 460.9→99.1
Primary 20 10 412.9→369
PFOA 7.11 3.6
Confirmatory 20 16 412.9→169
Primary 15 32 398.9→80.1
PFHxS 7.39 1
Confirmatory 15 32 398.9→99.1
Primary 15 10 362.9→319
PFHpA 6.35 4.1
Confirmatory 15 15 362.9→169
Primary 15 8 312.9→269
PFH
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