ISO/FDIS 25652

ISO/DISFDIS 25652
ISO/TC 190/SC 3
Secretariat: DIN
Date: 2026-01-0509-28
Soil, sludge, waste, sediment — Analysis of perfluoroalkyl and
polyfluoroalkyl substances (PFAS) by high performance liquid
chromatography (HPLC) and mass spectrometry
Les sédiments, leSédiments, sol, les boues et les déchets — Analyse des substances perfluoroalkylées et
polyfluoroalkylées (PFAS) par HPLCchromatographie liquide à haute performance (CLHP) et spectrométrie de
masse
FDIS stage
Warning for WD’s and CD’s
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ISO/DISFDIS 25652:20252026(en)
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iii
ISO/DISFDIS 25652:20252026(en)
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Interferences . 8
5.1 General . 8
5.2 Interferences in the extraction and cleaning and processing of extracts . 8
5.3 Interferences in the HPLC-MS/MS analysis . 8
6 Reagents . 9
7 Equipment . 11
8 Sample storage, extraction and analytical procedure . 12
8.1 Sample storage . 12
8.2 Sample pretreatment . 12
8.3 Extraction . 13
8.4 Purification of the extract . 13
8.5 HPLC-MS/MS analysis . 14
8.6 Chromatographic separation. 17
8.7 Instrumental detection limit . 17
8.8 Method blank . 17
9 Calibration . 18
9.1 General . 18
9.2 Calibration of the method using an internal standard . 18
9.3 Concentration calculation based on calibration with internal standards . 19
9.4 Handling of samples outside the scope of the calibration . 20
10 Evaluation . 20
10.1 Identification . 20
10.2 Validity of the calibration . 21
10.3 Quantification of branched isomers . 21
10.4 Recovery of isotope labelled standards . 21
11 Expression of results . 22
12 Test report . 22
Annex A (informative) Flow chart . 23
Annex B (informative) Example chromatograms . 25
Annex C (informative) Examples of chromatographic separation of linear and branched PFAS . 29
Annex D (informative) Validation results . 35
Bibliography . 58

iv
ISO/DISFDIS 25652:20252026(en)
Foreword
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ISO documentdocuments should be noted. This document was drafted in accordance with the editorial rules
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This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical
and physical characterization, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 444, Environmental characterization of solid matrices in collaboration with
Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical and physical characterization, in ,
in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
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v
ISO/DISFDIS 25652:20252026(en)
Introduction
Per-Perfluoroalkyl and polyfluoroalkyl substances (PFAS) isare a large group of industrially produced
fluorinated hydrocarbons (alkyl substances). PFAS contain a fully (per-) or partially (poly-) fluorinated carbon
chain. The length normally ranges from 2 to 18 carbon atoms. The best known PFAS are PFOS (perfluorooctane
1)
sulfonic acid) and PFOA (perfluorooctanoic acid) .
Since 2018, explicit attention has been requested for PFAS residues in soil trading. Due to the potential risks
of the substance group or the lack of information about it, the target values for soil trading in some countries
are relatively low at the level of a few µg / /kg. For this reason, in many cases the chemical analyses are decisive
in decision-making for soil trading and determining the possibilities for use of soil and dredged material
released in projects. Precisely because of the diffuse occurrence of PFAS and the relatively strict target values,
there is a generic need for a validated analysis method with a substantiated reporting limit and uniformity in
the analysis methods and the associated pre-treatment.
The need for validation and uniformity does not only affect chemical analysis. The sampling strategy and
method of performing the fieldwork also determine the final result. To this end, various guidelines have been
and will be provided in other contexts and assessment guidelines and protocols have been drawn up.

1)
Both substances, PFOS and PFOA, consist of eight and seven fully fluorinated carbon atoms, respectively, with PFOS
additionally having a sulfonate as a "“functional group"” on the last carbon atom and PFOA a carboxyl group.

vi
ISO/DISFDIS 25652:20252026(en)
Soil, sludge, waste, sediment — Analysis of perfluoroalkyl and
polyfluoroalkyl substances (PFAS) by high perfomanceperformance
liquid chromatography (HPLC) and mass spectrometry
WARNING — Persons using this document should be familiar with normal laboratory practice. This
document does not purport to address all of the safety problems, if any, associated with its use. It is
the responsibility of the user to establish appropriate safety and health practices.
IMPORTANT — Tests conducted in accordance with this document shall be carried out by suitably
qualifiedtrained staff.
1 Scope
This document specifies a method for quantitative determination of various per-perfluorinated and
polyfluorinated hydrocarbons by means of high-performance liquid chromatography (HPLC) and mass
spectrometry in soil, sludge, sediment and waste (see Table 1).
Annex D provides more information on the LOQ’slimits of quantification (LOQs) reachable with this
procedure.
The method can be applied to the analysis of additional perfluoroalkyl and polyfluoroalkyl substances (PFAS)
not specified in the scope, if validity is proven by proper in-house validation protocols, particularly for volatile
compounds that can be lost during preparation.
For each target compound, all branched and non-branched are quantified together. In this method the amount
of linear and branched PFAS is quantified using the response factor of the linear PFAS in the calibration
standard and the total area of the linear and branched PFAS ((Annex C gives more explanation).
Alternatively, the linear isomer and sum of branched isomers can be quantified separately and the sum of both
can be calculated provided a complete separation of the linear isomer from the branched isomers is obtained.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
perfluoroalkyl and polyfluoroalkyl substances
PFAS
organic compounds with replacement of most or all hydrogen atoms by fluorine in the aliphatic chain
structure
Note 1 to entry: The term is used in the broader sense for per-perfluoroalkyl and polyfluoroalkyl substances (PFAS), and
perperfluorinated and polyfluorinated compounds (PFC) as well.
ISO/DISFDIS 25652:20252026(en)
[SOURCE: ISO 21675:2019, 3.1]
4 Principle
The compounds listed in Table 1 are extracted from the prepared, homogenized sample material with
methanol, acetonitrile or a mixture of the two under basic conditions after addition of isotopically labelled
PFAS compounds. The extracts are purified if necessary, for example with activated carbon. The identification
and quantification are performed by high performance liquid chromatography coupled with a mass selective
detector (HPLC-MS / /MS). The content of each PFAS compound is calculated with the internal standard
method.
For many substances to which this document is applicable a limit of quantification (LOQ) of 0,01 to 0,1
µg/kgDM can be achieved. See also Annex DAnnex D.
All compounds of Table 1 were tested during an international inter laboratory trial in Europe in the period
December 2023 to April 2024. Table 1The table specifies for which the criteria of an inter laboratory
coefficient of variation of reproducibility (C C ) of 50 % was not reached. See Annex D for more details.
VR V,R
The validity of the procedure has been proven for soil, sediment and sludge samples and for a selection of
waste samples. For other waste types than mentioned in Annex D the laboratory shall validate the suitability
of the procedure of this standard.
Note NOTE For many compounds in the river clay, sediment and marine sediment sample Table 1Table 1 gives
“Cons <” as conclusion, where Annex DAnnex D might show positive results. Annex DAnnex D in that case shows the
results of the few labs with a positive result, where Table 1Table 1,, based on all raw data, clarifies that most of the labs
reported a “<-“< ‒ value”.
Table 1 — Summary of the conclusions of the validation per compound and per matrix
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
2,2,3,3,4,4,4-
Perfluorobut C4HF7 375– Yes Ye
PFBA Heptafluorobutanoic   Yes Yes
anoic acid O2 22–4 (7) s
acid
2,2,3,3,4,4,5,5,5-
Perfluorope C5HF9 2706– Con Ye
PFPeA Nonafluoropentanoic - No Yes Yes
ntanoic acid O2 90–3 s < s
acid
2,2,3,3,4,4,5,5,6,6,6-
Perfluorohe C6HF1 307– Con Ye
PFHxA Undecafluorohexanoic Yes Yes Yes Yes
xanoic acid 1O2 24–4 s < s
acid
2,2,3,3,4,4,5,5,6,6,7,7,7-
Perfluorohe C7HF1 375– Con Ye
PFHpA Tridecafluoroheptanoic Yes Yes Yes Yes
ptanoic acid 3O2 85–9 s < s
acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluorooct C8HF1 8,8- 335– Ye
PFOA Yes Yes Yes Yes Yes
anoic acid 5O2 Pentadecafluorooctanoi 67–1 s
c acid
Perfluorooct
PFOA C8HF1
anoic acid
branched 5O2
branched
Perfluorono C9HF1 375– Con Ye
2,2,3,3,4,4,5,5,6,6,7,7,8,
PFNA Yes Yes Yes Yes
nanoic acid 7O2 95–1 s < s
8,9,9,9-
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
Heptadecafluoro-
nonanoic acid
Perfluorono
PFNA C9HF1
nanoic acid
branched 7O2
branched
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluorodec C10HF 8,9,9,10,10,10- 335– Con Ye
PFDA Yes Yes Yes Yes
anoic acid 19O2 Nonadecafluorodecanoi 76–2 s < s
c acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluoroun
C11HF 8,9,9,10,10,11,11,11- 2058– Con Ye
PFUnDA decanoic Yes Yes Yes Yes
21O2 Henicosafluoroundecan 94–8 s < s
acid
oic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluorodo 8,9,9,10,10,11,11,12,12,
C12HF 307– Con Ye
PFDoDA decanoic 12- Yes Yes Yes Yes
23O2 55–1 s < s
acid Tricosafluorododecanoi
c acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluorotri 8,9,9,10,10,11,11,12,12
C13HF 72629 Con Ye
PFTrDA decanoic ,13,13,13- Yes Yes Yes No
25O2 –94–8 s < s
acid Pentacosafluorotrideca
noic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
Perfluorotet 8,9,9,10,10,11,11,12,12
C14HF 376– Cons Con Ye
PFTeDA ra-decanoic ,13,13,14,14,14 - Yes Yes Yes
27O2 06–7 < s < s
acid Heptacosafluorotetra -
decanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
8,9,9,10,10,11,11,12,12
Perfluorohe
C16HF ,13,13,14,14,15,15,16,1 67905 Cons Con Con Ye
PFHxDA xa-decanoic Yes Yes
31O2 6,16,16 - - –19–5 < s < s < s
acid
Hentriacontafluorohex
a -decanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,
8,9,9,10,10,11,11,12,12
Perfluorocta ,13,13,14,14,15,15,16,1
C18HF 16517 Cons Con Con Yes Ye Yes
PFODA -decanoic 61
35O2 –11–6 < s < s < (6) s (7)
acid 6,17,17,18,18,18 -
Pentatriacontafluoro -
octadecanoic acid
Perfluorobut 1,1,2,2,3,3,4,4,4-
C4HF9 375– Cons Con Ye
PFBS ane-sulfonic Nonafluorobutane-1- Yes Yes Yes
O3S 73–5 < s < s
acid sulfonic acid
Perfluorope 1,1,2,2,3,3,4,4,5,5,5-
C5HF1 2706– Cons Con Con Ye
PFPeS ntane- Undecafluoropentane- Yes Yes
1O3S 91–4 < s < s < s
sulfonic acid 1-sulfonic acid
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
Perfluorohe 1,1,2,2,3,3,4,4,5,5,6,6,6-
C6HF1 355– Con Yes Ye
PFHxS xane- Tridecafluorohexane-1- Yes Yes Yes
3O3S 46–4 s < (6) s
sulfonic acid sulfonic acid
Perfluorohe
xane-
PFHxS C6HF1
sulfonic
branched 3O3S
acid branche
d
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorohe 7,
C7HF1 375– Con Con Ye
PFHpS ptane- 7- Yes Yes Yes
5O3S 92–8 s < s < s
sulfonic acid Pentadecafluoroheptan
e-1-sulfonic acid
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorooct 7,
C8HF1 1763– Ye
PFOS ane-sulfonic 8,8,8- Yes Yes Yes Yes Yes
7O3S 23–1 s
acid Heptadecafluorooctane
-1-sulfonic acid
Perfluorooct
PFOS ane-sulfonic C8HF1
branched acid branche 7O3S
d
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorono
C9HF1 7,8,8,9,9,9- 68259 Cons Con Con Ye
PFNS nane- Yes Yes
9O3S Nonadecafluoro- –12–1 < s < s < s
sulfonic acid
nonane-1-sulfonic acid
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorodec
C10HF 7,8,8,9,9,10,10,10- 335– Cons Con Con Ye
PFDS ane-sulfonic Yes Yes
21O3S Henicosafluorodecane- 77–3 < s < s < s
acid
1-sulfonic acid
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluoroun 7, 74978
C11HF Cons Con Con
PFUnDS decane- 8,8,9,9,10,10,11,11,11- 6–16– Yes No Yes
23O3S < s < s <
sulfonic acid Tricosafluoroundecane 1
-1-sulfonic acid
C12HF 1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorodo 25O3S 7,8,8,9,9,10,10,11,11,12
79780 Cons Con Con
PFDoDS decane- C12HF ,12,12- Yes No Yes
–39–5 < s < s <
sulfonic acid 2 Pentacosafluorodo-
5O3S decane-1-sulfonic acid
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorotri 7,8,8,9,9,10,10,11,11,12 79156
C13HF Cons Con Con
PFTrDS decane- ,12,13,13,13 - 3–89– No No No
27O3S < s < s <
sulfonic acid Heptacosafluorodo- 8
decane -1-sulfonic acid
4:2
3,3,4,4,5,5,6,6,6- 75712
Fluorotelom C6H5F Cons Con Con Ye
4:2 FTS Nonafluorohexane-1- 4–72– Yes Yes
er sulfonic 9O3S < s < s < s
sulfonic acid 4
acid
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
C8H5F
6:2
13O3S 3,3,4,4,5,5,6,6,7,7,8,8,8-
Fluorotelom 27619 Cons Con Ye
6:2 FTS C8H5F Tridecafluorooctane-1- Yes No Yes
er sulfonic –97–2 < s < s
1 sulfonic acid
acid
3O3S
C16H9
6:2
F26O4 bis(3,3,4,4,5,5,6,6,7,7,8,
fluorotelome 57677 Yes
6:2 diPAP PC16H 8,8-tridecafluorooctyl)
r phosphate –95–9 (4)
9F hydrogen phosphate
diester
26O4P
3,3,4,4,5,5,6,6,7,7,8,8,9,
C18H9
6:2 8:2 9,10,10,10-
F30O4 94391
fluorotelome heptadecafluorodecyl Cons Con Yes
6:2 8:2 diPAP PC18H 3–15–
r phosphate 3,3,4,4,5,5,6,6,7,7,8,8,8- < s < (4)
9F 3
diester tridecafluorooctyl
30O4P
hydrogen phosphate
C10H5
8:2 3,3,4,4,5,5,6,6,7,7,8,8,9,
F17O3
Fluorotelom 9,10,10,10- 39108 Cons Con Ye
8:2 FTS SC10H Yes Yes Yes
er sulfonic Heptadecafluorodecane –34–4 < s < s
5F
acid -1-sulfonic acid
17O3S
C12H5
10:2 3,3,4,4,5,5,6,6,7,7,8,8,9,
F21O3 12022
Fluorotelom 9,10,10,11,11,12,12,12- Cons Con Ye
10:2 FTS SC12H 6–60– Yes Yes No
er-sulfonic Henicosafluorododecan < s < s
5F 0
acid e-1-sulfonic acid
21O3S
8:2
C10H2
Fluorotelom 3,4,4,5,5,6,6,7,7,8,8,9,9,
F16O2
er 10,10,10- 70887 Cons Con Con Yes Ye
8:2 FTUCA C10H2 Yes
unsaturated Hexadecafluorodec-2- –84–2 < s < s < (6) s
F
carboxylic enoic acid
16O2
acid
C20H9
8:2 Bis(3,3,4,4,5,5,6,6,7,7,8,
F34O4
Perfluoroalk 8,9,9,10,10,10- 678– Cons Con
8:2 diPAP PC20H Yes Yes No Yes
yl phosphate heptadecafluorodecyl) 41–1 < s <
9F
diester hydrogen phosphate
34O4P
1,1,2,2,3,3,4,4,5,5,6,6,7,
Perfluorooct C8H2F
7,8,8,8- 754– Ye
PFOSA ane- 17NO2 Yes Yes Yes Yes Yes
Heptadecafluoro-1- 91–6 s
sulfonamide S
octanesulfonamide
Perfluorooct
C8H2F
PFOSA ane-
17NO2
branched sulfonamide
S
branched
N- 1,1,2,2,3,3,4,4,5,5,6,6,7,
methylperfl C9H4F 7,8,8,8- Ye
31506 Cons Yes Con Yes
MePFOSA uoro- 17NO2 Heptadecafluoro-N- s Yes
–32–8 < (4) s < (7)
octanesulfon S methyl-1- (7)
amide octanesulfonamide
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
N-
methylperfl
C9H4F
MePFOSA uoro-
17NO2
branched octanesulfon
S
amide
branched
N- 2-
methylperfl [1,1,2,2,3,3,4,4,5,5,6,6,7
C11H6
uoro- ,7,8,8,8- 2355– Cons Ye
MePFOSAA F17NO Yes Yes Yes Yes
octanesulfon Heptadecafluorooctyl- 31–9 < s
4S
amidoacetic sulfonyl(methyl)amino
acid ]acetic acid
N-
methylperfl
uoro- C11H6
MePFOSAA
octanesulfon F17NO
branched
amidoacetic 4S
acid
branched
N- N-Ethyl-
ethylperfluo C10H6 1,1,2,2,3,3,4,4,5,5,6,6,7, Ye
4151– Cons Yes Con Yes Yes
EtPFOSA ro- F17NO 7,8,8,8- s
50–2 < (7) s < (6) (7)
octanesulfon 2S heptadecafluorooctane- (7)
amide 1-sulfonamide
N-
ethylperfluo
C10H6
EtPFOSA ro-
F17NO
branched octanesulfon
2S
amide
branched
2-
N-
[Ethyl(1,1,2,2,3,3,4,4,5,
ethylperfluo C12H8
5,6,6,7,7,8,8,8- 2991– Ye
EtPFOSAA rooctane- F17NO Yes Yes Yes Yes Yes
heptadecafluoro- 50–6 s
sulfonamido 4S
octylsulfonyl)amino]ac
acetic acid
etic acid
N-
ethylperfluo
C12H8
EtPFOSAA rooctane-
F17NO
branched sulfonamido
4S
acetic acid
branched
N-
N-Methyl-
methylperfl Ye
C5H4F 1,1,2,2,3,3,4,4,4- 68298 Cons Con Con Yes Yes
MePFBSA uoro- s
9NO2S nonafluorobutane-1- –12–4 < s < s < (5) (6)
butanesulfo (6)
sulfonamide
namide
N-
15938 Ye
2-
C7H6F Cons Con Con
methylperfl
MePFBSAA 1–10– No s Yes
[Methyl(1,1,2,2,3,3,4,4,
9NO4S < s < s <
uoro-
9 (6)
4-
butanesulfo
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
namidoaceti nonafluorobutylsulfony
c acid l)amino]acetic acid
Nonafluoro- 2,2-difluoro-2-[1,1,2,2-
3,6- C5HF9 tetrafluoro-2-(-
NFDHpA 2–58–
dioxaheptan O4 (trifluoromethoxy)etho
oic acid xy]acetic acid
Perfluorobut 1,1,2,2,3,3,4,4,5,5,6,6,6-
C4H2F 30334 Cons Con Con Ye
PFBSA ane- Nonafluoro-1- No Yes
9NO2S –69–1 < s < s < s
sufonamide butanesulfonamide
Perfluoro-3- 2,2,3,3-tetrafluoro-3- Ye
C4HF7 377– Yes
PFMPA methoxypro (trifluoromethoxy)prop    s
O3 73–1 (3)
panoic acid anoic acid (3)
2,2,3-Trifluoro-3-
4,8-Dioxa-
[1,1,2,2,3,3-hexafluoro- 91900
3H- C7H2F Cons Con Con Ye
DONA 3-(- 5–14– Yes Yes
perfluorono 12O4 < s < s < s
(trifluoromethoxy)prop 4
nanoic acid
oxy]propanoic acid
7H- 2,2,3,3,4,4,5,5,6,6,7,7- Ye
C7H2F 1546– Cons Con Con
HPFHpA Perfluorohe Dodecafluoroheptanoic Yes s Yes
12O2 95–8 < s < s <
ptanoic acid acid (7)
Perfluoro-3– 2,2,3,4,4,5,5,6,6,7,8,8,8-
17215 Ye
7- C10HF Tridecafluoro-3,7- Cons Con Con Yes
P37DMOA 5–07– s Yes
dimethyloct 19O2 bis(trifluoromethyl)oct < s < s < (7)
6 (7)
anoic acid anoic acid
Perfluorohe C6H2F 1,1,2,2,3,3,4,4,5,5,6,6,6- Ye
41997 Cons Con Con Yes Yes
PFHxSA xane-sulfon- 13NO2 tridecafluorohexane-1- s
–13–1 < s < s < (7) (5)
amide S sulfonamide (6)
2,2,3,3,4,4-hexafluoro-
Perfluoro-4- 86309
C5HF9 4-(-
PFMBA methoxybut 0–89–
O3 (trifluoromethoxy)buta
anoic acid 5
noic acid
9- 2-(6-Chloro-
Chlorohexad 1,1,2,2,3,3,4,4,5,5,6,6-
C8HCl 75642
ecafluoro-3- dodecafluorohexoxy)- Cons Con Con Ye
9Cl-PF3ONS F16O4 6-58- Yes Yes
oxanonane- 1,1,2,2- < s < s < s
S 1
1-sulfonic tetrafluoroethanesulfo
acid nic acid
2H,2H,3H,3 4,4,5,5,6,6,7,7,8,8,9,9,1
H-perfluoro C11H5 0,10,11,11,11- 34598 Cons Con Yes
4H-PFUnDA Yes No Yes
undecanoic F17O2 Heptadecafluoroundec –33–9 < s < (6)
acid anoic acid
perfluoro-4- 1,2,2,3,3,4,5,5,6,6-
Ye
ethylcyclohe C8HF1 decafluoro-4-(1,1,2,2,2- 646– Cons Con Con Yes
4-PFECHS  s
xane 5O3S pentafluoroethyl)cyclo 83–3 < s < s < (6)
(7)
sulfonic acid hexane-1-sulfonic acid
2,3,3,3-Tetrafluoro-2-
Perfluoro-2–
C6HF1 (1,1,2,2,3,3,3- 13252 Cons Con Con Ye
HFPO-DA propoxypro Yes Yes
1O3 heptafluoropropoxy)- –13–6 < s < s < s
panoic acid
propanoic acid
ISO/DISFDIS 25652:20252026(en)
a
Abbr. Analyte Formu IUPAC name CAS- RivC Sed Mar Wa Soi Slu
b
la RN lay Sed ste l dg
e
a IUPAC      : International Union of Pure and Applied Chemistry
b CAS-RN    : Chemical Abstract Services Registry Number
1 The branched isomers mentioned in this table are examples, other branched isomers do exist.

Further explanation:
RivClay: River Clay
river clay
Sed: Sediment
sediment
MarSed: Marine Sediment
marine sediment
Yes        : criterion of CVR < 50 % was met with 8 or more laboratories
Yes(n): )     criterion of CVR < 50 % was met with n laboratories
No         : criterion was not met with 8 or more laboratories
Cons <     : most of the results consistently < - ‒ value
5 Interferences
5.1 General
In particular, process interferences can be caused by contact of the sample with polytetrafluoroethylene
(PTFE) materials. To avoid raised blank values, materials of glass, steel, polyether ether ketone (PEEK),
polypropylene (PP) or high density polyethylene (HDPE) should preferably be used for sampling, extraction
and analysis.
5.2 Interferences in the extraction and cleaning and processing of extracts
Efforts should be taken to minimize background levels in method blank materials such that the method blank
is maximum half of the reporting limit (8.8().). Low molecular residuals in fluoropolymer-containing materials
such as Viton (Fluorocarbonfluorocarbon rubber), PVDF (Polyvinylideenfluoridepolyvinylideenfluoride), etc.,
which are often used in LC equipment, can cause blank values, e.g. in the case of PFOA. Sampling vessels (7.1())
and sample vials (7.4()) shall be checked for possible background contamination before use.
5.3 Interferences in the HPLC-MS / /MS analysis
Either peak tailing, peak fronting or broadened peaks or a combination of one of these are indicative of
interferences in chromatography. Sample matrix components can affect the ionization of the target
substances. This can result in suppression or enhancement of the ionization. Such matrix interferences can be
detected and corrected by using authentic isotopically labelled internal standards. Substances with similar
retention times that can produce ions with similar mass to charge ratios (m/z) to those produced by the target
analytes can interfere with the determination. These interferences can lead to incompletely resolved signals
and/or additional signals in the mass chromatograms of target substances. Depending on their levels in the
sample, such substances can affect the accuracy and precision of the results. As long as the peak of interest can
be separately integrated from interferences, it may be used.
Typical contamination sources in the LC system include vacuum degassers, frits and tubes as well as pump
head seals. In the case of such interferences, degassing of the eluents, for example, can be carried out using
helium instead of vacuum degassers. Fluoropolymer frits and tubes shall be replaced by frits and tubes made
of stainless steel or PEEK. If available, pump head seals made of PE shall be used.
ISO/DISFDIS 25652:20252026(en)
A delay column supports avoiding background contamination from within the instrument (7.13().).
6 Reagents
Always use certified or analytical grade reagents whenever possible. Store the reagents in glass or
polypropylene bottles (7.10) fitted with a metal or polypropylene lid. Avoid using lids containing
fluoropolymers and verify reagents are free from contaminants by taking regular blank measurements, see
the method blank procedure (8.8.).
6.1 Ultrapure water, H O, deionized.
6.2 Acetonitrile, CH CN.
6.3 Methanol, CH OH.
OH, can be used.
6.4 Sodium hydroxide, NaOH, alternatively ammonium hydroxide, NH
6.5 Acetic acid, CH COOH, > 96 % (mass fraction).
6.6 Ammonium formate, NH HCO , alternatively ammonium acetate NH CO CH or ammonium carbonate
4 2 4 2 3
(NH ) CO can be used.
4 2 3
6.7 Extraction solvent, acetonitrile:methanol (1:1) with 0,05 mol/l sodium hydroxide.
Weigh e.g. 2 g sodium hydroxide (6.4()) into a mixture of 500 ml acetonitrile (6.2()) and 500 ml methanol
(6.3().).
Other solvents with similar chemical properties and other concentrations of sodium hydroxide than those
described here may be used, provided that comparability with the operating procedure of the present
standard is demonstrated.
6.8 Conditioning fluid, acetonitrile:methanol:water (1:1:1).
Mix e.g. 250 ml of water (6.1()) with 250 ml of acetonitrile (6.2()) and 250 ml of methanol (6.3().).
6.9 Elution liquid, acetonitrile:methanol (1:1) with 0.,05 mol/l acetic acid.
Add e.g. 0,3 ml acetic acid (6.5()) to a mixture of 50 ml acetonitrile (6.2()) and 50 ml methanol (6.3().).
6.10 Mobile phase, ammonium formate eluate solution with 5 % methanol.
Weigh e.g. 1,2 g of ammonium formate (6.6()) into a mixture of 38003 800 ml of water (6.1()) and 200 ml of
methanol (6.3().).
6.11 Reference standards.
Only use reference standards that consist of at least 95 % (mass fraction) of the linear isomer, for the
quantitative determination of the analytes (see Table 1).
NOTE Ampoules of individual compounds or mixtures thereof are commercially available.
6.12 Isotope labelled standards.
Isotope labelled standards are used for internal standard calibration. This allows correction for loss during
the analytical process or other changes in analytical conditions that can lead to bias.
ISO/DISFDIS 25652:20252026(en)
NOTE Ampoules of individual isotope labelled standards or mixtures thereof are commercially available.
6.13 Preparation of stockStock, intermediate and calibration solutions.
Calculate the concentration of all reference and calibration solutions on the basis of the dissolved anion
amount (neutral compound). All solutions are stored in the dark at 5 ± ± 3 °C. The solutions have a shelf life
of at least one year. The solutions are brought to room temperature before use. For some compounds
sonication or vortex, or both, is required.
6.13.1 Stock solutions of reference standards.
Prepare stock solutions of the reference standards (6.11()) in acetonitrile (6.2()) or methanol (6.3().).
6.13.2 Stock solutions from isotope labelled standards.
Prepare stock solutions of the isotope-labelled standards solutions (6.12()) in acetonitrile (6.2()) or methanol
(6.3().).
NOTE 13C HFPO-DA is not stable in acetonitrile.
6.13.3 Stock solutions of reference standards for QC for verification of the calibration curve.
Prepare stock solutions of independent reference standards (6.11()) in acetonitrile (6.2()) or methanol
(6.3().). Independent reference standards are preferably obtained from different suppliers. A minimum of one
third of the analytes in the stock solutions of reference standards (6.13.1()) should be present in the
calibration verification solution. Each calibration verification solution should, if relevant for the compounds
to be analysed, contain representative compounds for at least the following groups:
— Perfluoratedperfluorated carboxylic acids: PFBA, PFHxA, PFOA, PFDA, PFTeDA, PFODA;
— Perfluoratedperfluorated sulfonic acids: PFBS, PFHxS, PFOS, PFDS, PFDoDS;
— Fluorotelomersfluorotelomers: 4:2 FTS, 10:2 FTS;
— Perfluoroperfluoro-sulfonamides: PFBSA;
— Perfluoroperfluoro-sulfonamide acetic acids: EtPFOSAA, MePFOSAA;
— Variousvarious: DONA, 4-PFECHS, HFPO-DA, 8:2 diPAP.
Preferably use standards from a different supplier for the calibration verification solution or at least different
mixtures from the same supplier (if available).
NOTE HFPO-DA is not stable in acetonitrile.
6.13.4 Intermediate solution of reference standards.
Prepare an intermediate solution of the stock solutions of reference standards (6.13.1()) in methanol (6.3())
or acetonitrile (6.2) (the same as used for the stock solution) at a concentration of e.g. 0,2 µg / /ml.
6.13.5 Intermediate solution of isotope-labelled standards.
Prepare an intermediate solution of the stock solutions of isotope-labelled standards (6.13.2()) in methanol
(6.3()) or acetonitrile (6.2) (the same as used for the stock solution) with a concentration of e.g. 0,2 µg / /ml.
6.13.6 Intermediate solution of reference standards for QC verification of the calibration curve.
ISO/DISFDIS 25652:20252026(en)
Prepare an intermediate solution of the stock solutions of independent reference standards for QC verification
of the calibration curve (6.13.3()) in methanol (6.3()) or acetonitrile (6.2) (the same as used for the stock
solution) with a concentration of e.g. 0,2 µg / ml.
6.13.7 Calibration solutions from reference standards.
This is a series of multi-component calibration solutions (at least five different solutions) in increasing
concentration prepared in methanol (6.3()) or acetonitrile (6.2) (the same as used for the stock solution) from
the intermediate solution of reference standards (6.13.4()) with a concentration range of, as an example,
0.,02 ng / /ml to 20 ng / /ml. A fixed amount of the isotope-labelled standards (6.13.5()) intermediate
solutions are added to each calibration solution.
NOTE Instead of adding the isotope labelled standards to the calibration solutions, injection can also be performed
by the instrument.
6.13.8 Spike solution isotope-labelled standards.
()) or
Prepare a spike solution of the intermediate isotope-labelled standards (6.13.5()) in methanol (6.3
acetonitrile (6.2) (the same as used for the stock solution) with a concentration of e.g. 0,02 µg/ml. The
concentration level should be at least three times the corresponding level of the limit of quantification.
6.13.9 Solutions of independent standards for verification of the calibration curve.
Prepare two solutions in methanol (6.3()) or acetonitrile (6.2) (the same as used for the stock solution) from
the intermediate solution of independent standards for verification of the calibration curve (6.13.6()) with a
concentration preferably in the beginning and end of the calibration range.
6.14 Purification columns; disposable adsorption material.
— SPE (Solid Phase Extractionsolid phase extraction) adsorption material: Activatedactivated carbon, such
2)
as ENVI-Carb .
— Other adsorption materials may be used provided equivalent results are obtained. Good results are
obtained using 250 mg/ 6 ml tubes.
6.15 Nitrogen gas, N .
6.16 Silver sand.
6.17 Neutralization solution.
Weigh e.g. 3,8 g ammonium acetate (6.6()) in 100 ml water (6.1().).
7 Equipment
All equipment and utensils that come into contact with the sample or extract shall be free from PFAS
contaminants analysed. If a background signal of PFAS is observed, the equipment and utensils used should
be cleaned with water (6.1()) and methanol (6.3().). All equipment shall be calibrated or checked according to
official standards or proprietary internal procedures.
7.1 Sample containers with screw cap, free from background signal.

2)
ENVI-Carb is an example of a suitable product available commercially. This information is given for the convenience of
users of this document and does not constitute an endorsement by ISO of these products.this product.

ISO/DISFDIS 25652:20252026(en)
Sample containers made of glass, polypropylene, PET or high-density polyethylene (HDPE) or stainless steel.
7.2 Balance, with a resolution of at least 1 % of the weighed amount.
7.3 Syringes.
7.4 Test tubes, sampling vials of appropriate volume, e.g. made of Polypropylenepolypropylene.
7.5 Pasteur pipettes.
7.6 Pipettes of appropriate volume.
7.7 Evaporation block.
7.8 Shaking device, with horizontal movement (200 to 300 strokes per min).
7.9 Centrifuge.
7.10 Polypropylene containers.
7.11 Liquid chromatograph with gradient set-up with mass spectrometer.
Mass spectrometric detector (MS/MS), preferably tandem mass spectrometer with electrospray ionization
(ESI).
NOTE For the procedure described in this standard, other MS techniques can be used as well, e.g. time-of-flight mass
spectrometry (TOF/MS), provided the identification of the analytes has been verified and documented for the respective
applications.
7.12 “Reversed phase” HPLC column, C18 or equivalent.
7.13 Delay column.
Background contamination from the instrument can be controlled by using a delay column. A delay column is
attached between the solvent mixer and the injection valve to chromatographically separate these background
contaminants, originating from the instrument or mobile phases, or both, from the target analytes.
7.14 HPLC vial, e.g. a 2 ml Polypropylenepolypropylene vial, with a fluorine screw cap.
8 Sample storage, extraction and analytical procedure
8.1 Sample storage
Samples shall be analysed within 28 days. If necessary, sludge samples should be stored according to
ISO 5667-15. Dried samples can be stored at room temperature up to one month. Soil samples should be stored
according to ISO 18512.
8.2 Sample pretreatment
The sample shall be dried. Drying can be performed e.g. by freeze drying (preferred for sewage sludge) or
drying at a maximum of 40 °C. Chemical drying (with sodium sulfate) is also a possibility. It is recommended
that a field moist soil sample or a sludge sample be pre-treated following standards such as EN 16179, and
that waste samples be treated according to standards like EN 15002 or any other suitable standard.
Drying of the (partial) sample is permitted up to a maximum of 40 °C to minimize loss of volatile PFAS
compounds.
ISO/DISFDIS 25652:20252026(en)
8.3 Extraction
The different steps for the procedure described here are an example and are summarized in Annex A,
Figure A.1Figure A.1.
Remove the spike solution of the isotope internal standard solution (6.13.8()) from the refrigerator and allow
it to reach room temperature.
At least one method blank is prepared for each series.
Depending on the grinding fineness, 1 g to 10 g of dried sample is weighed into a polypropylene container
(7.10()) or a suitable glass container. To all samples e.g. 100 µl isotopically labelled spike solution (6.13.8) is
() added. All samples are shaken briefly by hand to mix the added solution with the sample.
An amount of acetonitrile (6.2()) or methanol (6.3()) or a mixture (6.7()) of acetonitrile:methanol (1:1) is used
as extraction solvent. Add 0,05 mol/l sodium hydroxide or ammonium hydroxide (6.4() are added) to all
samples in order to getobtain a liquid-solid ratio from at least 2 to 4 (e.g. 20 ml to 5 g).
NOTE The use of only acetonitrile is not possible if HFPO-DA has to be analysed, as this compound is not stable in
acetonitrile.
Other solvents with similar chemical properties and other concentrations of sodium hydroxide than those
described here may be used, provided that comparability with the operating procedure of the present
standard is demonstrated.
The samples are placed on the shaker (7.8()) and shaken for a minimum of 60 minutes. Instead of shaking,
ultrasonication (at a maximum temperature of 55 ˚C °C) may be applied. After extraction, the samples are
placed in the centrifuge (7.9()) to remove particles. Alternatively, the sample can be left in the refrigerator for
sedimentation for at least 3 hours.
If no purification step (see 8.4)) is applied, add 100 µl ammonium acetate solution (6.17()) to 900 µl extract.
8.4 Purification of the ex
...