prEN ISO 25652

SLOVENSKI STANDARD
01-december-2025
Tla, usedline, blato in odpadki - Analiza perfluoroalkilnih in polifluoroalkilnih snovi
(PFAS) s tekočinsko kromatografijo visoke ločljivosti (HPLC) in masno
spektrometrijo (ISO/DIS 25652:2025)
Sediment, Soil, sludge and waste - Analysis of PFAS by HPLC and mass spectrometry
(ISO/DIS 25652:2025)
Boden, Sediment, Schlamm und Abfall - Analyse von PFAS durch HPLC und
Massenspektrometrie (ISO/DIS 25652:2025)
Sédiments, sol, boues et déchets - Analyse des PFAS par CLHP et spectrométrie de
masse (ISO/DIS 25652:2025)
Ta slovenski standard je istoveten z: prEN ISO 25652
ICS:
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 25652
ISO/TC 190/SC 3
Sediment, Soil, sludge and waste —
Secretariat: DIN
Analysis of PFAS by HPLC and mass
Voting begins on:
spectrometry
2025-10-27
Les sédiments, le sol, les boues et les déchets — Analyse des PFAS
Voting terminates on:
par HPLC et spectrométrie de masse
2026-01-19
ICS: 13.080.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
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Reference number
ISO/DIS 25652:2025(en)
DRAFT
ISO/DIS 25652:2025(en)
International
Standard
ISO/DIS 25652
ISO/TC 190/SC 3
Sediment, Soil, sludge and waste —
Secretariat: DIN
Analysis of PFAS by HPLC and mass
Voting begins on:
spectrometry
Les sédiments, le sol, les boues et les déchets — Analyse des PFAS
Voting terminates on:
par HPLC et spectrométrie de masse
ICS: 13.080.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland Reference number
ISO/DIS 25652:2025(en)
ii
ISO/DIS 25652:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 5
3 Terms and Definitions . 5
4 Principle . 5
5 Interferences . 5
5.1 General .5
5.2 Interferences in the extraction and cleaning and processing of extracts .5
5.3 Interferences in the HPLC-MS / MS analysis .6
6 Reagents . 6
7 Equipment . 8
8 Sample storage, extraction procedure and analytical analysis preservation . 9
8.1 Sample storage .9
8.2 Sample pretreatment .9
8.3 Extraction .10
8.4 Purification of the extract .10
8.5 HPLC-MS/MS analysis .10
8.6 Chromatographic separation . 13
8.7 Instrumental Detection Limit . 13
8.8 Method blank .14
9 Calibration . 14
9.1 General .14
9.2 Calibration of the method using an internal standard .14
9.3 Concentration calculation based on calibration with internal standards . 15
9.4 Handling of samples outside the scope of the calibration.16
10 Evaluation .16
10.1 Identification .16
10.2 Validity of the calibration .17
10.3 Quantification of branched isomers .17
10.4 Recovery of isotope labelled standards .17
11 Expression of results . 17
Annex A (informative) Flow Chart . 19
Annex B (informative) Example chromatograms .20
Annex C (informative) Examples of Chromatographic Separation of Linear and Branched PFAS .22
Annex D (informative) Validation results .27
Bibliography .42

iii
ISO/DIS 25652:2025(en)
Foreword
This document (prISO 25652:2025) has been prepared by Technical Committee CEN/TC 444 “Environmental
characterization”, in collaboration with Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3,
Chemical and physical characterization. The secretariat of CEN/TC 444 is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by XXXXXXX, and conflicting national standards shall be withdrawn at
the latest by XXXXXX.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,
Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland and Turkey.

iv
ISO/DIS 25652:2025(en)
Introduction
PFAS is a large group of industrially produced fluorinated hydrocarbons (alkyl substances). PFAS stands for
per- and polyfluoroalkyl substances and 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 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. That is why 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.

v
DRAFT International Standard ISO/DIS 25652:2025(en)
Sediment, Soil, sludge and waste — Analysis of PFAS by 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 — It is absolutely essential that tests conducted in accordance with this document be
carried out by suitably qualified staff.
1 Scope
This document specifies a method for quantitative determination of various perfluorinated hydrocarbons
by means of High-Performance Liquid Chromatography (HPLC) and mass spectrometry in soil, sludge,
sediment and waste (see Table 1).
For many substances to which this document applies a limit of quantification (LOQ) of 0,1 to 10 µg/kgdm
can be achieved. See also Annex D for more information regarding the LOQ’s reachable.
The method can be applied to the analysis of additional PFAS not specified in the scope, if validity is proven
by proper in-house validation protocols, particularly for volatile compounds that may 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 may 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.
All compounds of Table 1 were tested during an international inter laboratory trial in Europe in the period
December 2023 to April 2024. The table specifies for which the criteria of an interlaboratory standard
deviation (C ) of 50 % was not reached. See Annex D for more details.
VR
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.

ISO/DIS 25652:2025(en)
Table 1 — Summary of the conclusions per compound and per matrix (RivClay = River Clay; Sed = Sediment; MarSed = 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) 1)
a b
Abbr. Analyte Formula IUPAC name CAS-RN RivClay Sed MarSed Waste Soil Sludge
PFBA Perfluorobutanoic acid C4HF7O2 2,2,3,3,4,4,4-Heptafluorobutanoic acid 375–22–4  Yes Yes Yes
PFPeA Perfluoropentanoic acid C5HF9O2 2,2,3,3,4,4,5,5,5-Nonafluoropentanoic acid 2706–90–3 No Cons < No Yes Yes Yes
PFHxA Perfluorohexanoic acid C6HF11O2 2,2,3,3,4,4,5,5,6,6,6-Undecafluorohexanoic acid 307–24–4 Yes Cons < Yes Yes Yes Yes
PFHpA Perfluoroheptanoic acid C7HF13O2 2,2,3,3,4,4,5,5,6,6,7,7,7-Tridecafluoroheptanoic acid 375–85–9 Yes Cons < Yes Yes Yes Yes
2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Pentadecafluorooctanoic 335–67–1
PFOA Perfluorooctanoic acid C8HF15O2 Yes Yes Yes Yes Yes Yes
acid
Perfluorooctanoic acid
PFOA branched C8HF15O2
branched
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-Heptadecafluoro-nona- 375–95–1
PFNA Perfluorononanoic acid C9HF17O2 Yes Cons < Yes Yes Yes Yes
noic acid
Perfluorononanoic acid
PFNA branched C9HF17O2
branched
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Nonadecafluoro- 335–76–2
PFDA Perfluorodecanoic acid C10HF19O2 Yes Cons < Yes Yes Yes Yes
decanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Henic- 2058–94–8
PFUnDA Perfluoroundecanoic acid C11HF21O2 Yes Cons < Yes Yes Yes Yes
osafluoroundecanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Tri- 307–55–1
PFDoDA Perfluorododecanoic acid C12HF23O2 Yes Cons < Yes Yes Yes Yes
cosafluorododecanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,13-Pen- 72629–94–8
PFTrDA Perfluorotridecanoic acid C13HF25O2 Yes Cons < Yes Yes Yes No
tacosafluorotridecanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,1 376–06–7
PFTeDA Perfluorotetra-decanoic acid C14HF27O2 Cons < Cons < Yes Yes Yes Yes
4,14 -Heptacosafluorotetra -decanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,1 67905–19–5
PFHxDA Perfluorohexa-decanoic acid C16HF31O2 Cons < Cons < Cons < Yes Yes Yes
4,15,15,16,16,16 -Hentriacontafluorohexa -decanoic acid
2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,1 16517–11–6
PFODA Perfluorocta-decanoic acid C18HF35O2 4,14,15,15,16,16,17,17,18,18,18 -Pentatriacontafluoro Cons < Cons < Cons < Yes (6) Yes Yes (7)
-octadecanoic acid
Perfluorobutane-sulfonic 375–73–5
PFBS C4HF9O3S 1,1,2,2,3,3,4,4,4-Nonafluorobutane-1-sulfonic acid Cons < Cons < Yes Yes Yes Yes
acid
Perfluoropentane-sulfonic 1,1,2,2,3,3,4,4,5,5,5-Undecafluoropentane-1-sulfonic 2706–91–4
PFPeS C5HF11O3S Cons < Cons < Cons < Yes Yes Yes
acid acid
Perfluorohexane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,6-Tridecafluorohexane-1-sulfonic 355–46–4
PFHxS C6HF13O3S Yes Cons < Yes Yes Yes Yes
acid acid
PFHxS Perfluorohexane-sulfonic
C6HF13O3S
branched acid branched
Perfluoroheptane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,7-Pentadecafluorohep- 375–92–8
PFHpS C7HF15O3S Yes Cons < Cons < Yes Yes Yes
acid tane-1-sulfonic acid
1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Heptadecafluorooc- 1763–23–1
PFOS Perfluorooctane-sulfonic acid C8HF17O3S Yes Yes Yes Yes Yes Yes
tane-1-sulfonic acid
Perfluorooctane-sulfonic
PFOS branched C8HF17O3S
acid branched
ISO/DIS 25652:2025(en)
Table 1 (continued)
a b
Abbr. Analyte Formula IUPAC name CAS-RN RivClay Sed MarSed Waste Soil Sludge
Perfluorononane-sulphonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-Nonadecafluoro-non- 6825–12–1
PFNS C9HF19O3S Cons < Cons < Cons < Yes Yes Yes
acid ane-1-sulfonic acid
Perfluorodecane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Henicosafluo- 335–77–3
PFDS C10HF21O3S Cons < Cons < Cons < Yes Yes Yes
acid rodecane-1-sulfonic acid
Perfluoroundecane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10,11,11,11-Tri- 749786–16–1
PFUnDS C11HF23O3S Cons < Cons < Cons < Yes No Yes
acid cosafluoroundecane-1-sulfonic acid
Perfluorododecane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10,11,11,12,12,12-Pen- 79780–39–5
PFDoDS C12HF25O3S Cons < Cons < Cons < Yes No Yes
acid tacosafluorodo-decane-1-sulfonic acid
Perfluorotridecane-sulfonic 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10,11,11,12,12,13, 791563–89–8
PFTrDS C13HF27O3S Cons < Cons < Cons < No No No
acid 13,13 -Heptacosafluorodo-decane -1-sulfonic acid
4:2 Fluorotelomer sulfonic 757124–72–4
4:2 FTS C6H5F9O3S 3,3,4,4,5,5,6,6,6-Nonafluorohexane-1-sulfonic acid Cons < Cons < Cons < Yes Yes Yes
acid
6:2 Fluorotelomer sulfonic 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctane-1-sulfonic 27619–97–2
6:2 FTS C8H5F13O3S Cons < Cons < Yes No Yes Yes
acid acid
6:2 fluorotelomer phosphate bis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl) hydro- 57677–95–9
6:2 diPAP C16H9F26O4P
diester gen phosphate
3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl 943913–15–3
6:2 8:2 fluorotelomer phos-
6:2 8:2 diPAP C18H9F30O4P 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl hydrogen Cons < Cons <
phate diester
phosphate
8:2 Fluorotelomer sulfonic 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Heptadecafluorode- 39108–34–4
8:2 FTS C10H5F17O3S Cons < Cons < Yes Yes Yes Yes
acid cane-1-sulfonic acid
10:2 Fluorotelomer-sulfonic 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-Henic- 120226–60–0
10:2 FTS C12H5F21O3S Cons < Cons < Yes Yes Yes No
acid osafluorododecane-1-sulfonic acid
8:2 Fluorotelomer unsaturat- 3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-Hexadecafluoro- 70887–84–2
8:2 FTUCA C10H2F16O2 Cons < Cons < Cons < Yes (6) Yes Yes
ed carboxylic acid dec-2-enoic acid
8:2 Perfluoroalkyl phosphate Bis(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro- 678–41–1
8:2 diPAP C20H9F34O4P Cons < Cons < Yes Yes No Yes
diester decyl) hydrogen phosphate
1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Heptadecafluoro-1-oc- 754–91–6
PFOSA Perfluorooctane-sulfonamide C8H2F17NO2S Yes Yes Yes Yes Yes Yes
tanesulfonamide
PFOSA Perfluorooctane-sulfonamide
C8H2F17NO2S
branched branched
N-methylperfluoro-oc- 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Heptadecafluoro-N-me- 31506–32–8
MePFOSA C9H4F17NO2S Cons < Cons < Yes (7) Yes (7) Yes
tanesulfonamide thyl-1-octanesulfonamide
MePFOSA N-methylperfluoro-oc-
C9H4F17NO2S
branched tanesulfonamide branched
N-methylperfluoro-oc- 2-[1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-Heptadecafluorooc- 2355–31–9
MePFOSAA C11H6F17NO4S Cons < Yes Yes Yes Yes Yes
tanesulfonamidoacetic acid tyl-sulfonyl(methyl)amino]acetic acid
N-methylperfluoro-oc-
MePFOSAA
tanesulfonamidoacetic acid C11H6F17NO4S
branched
branched
N-ethylperfluoro-octanesul- N-Ethyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluo- 4151–50–2
EtPFOSA C10H6F17NO2S Cons < Cons < Yes (6) Yes (7) Yes (7)
fonamide rooctane-1-sulfonamide
EtPFOSA N-ethylperfluoro-octanesul-
C10H6F17NO2S
branched fonamide branched
ISO/DIS 25652:2025(en)
Table 1 (continued)
a b
Abbr. Analyte Formula IUPAC name CAS-RN RivClay Sed MarSed Waste Soil Sludge
N-ethylperfluorooctane-sul- 2-[Ethyl(1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptade- 2991–50–6
EtPFOSAA C12H8F17NO4S Yes Yes Yes Yes Yes Yes
fonamidoacetic acid cafluoro-octylsulfonyl)amino]acetic acid
N-ethylperfluorooc-
EtPFOSAA
tane-sulfonamidoacetic acid C12H8F17NO4S
branched
branched
N-methylperfluoro-bu- N-Methyl-1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulfon- 68298–12–4
MePFBSA C5H4F9NO2S Cons < Cons < Cons < Yes (5) Yes (6) Yes (6)
tanesulfonamide amide
N-methylperfluoro-bu- 2-[Methyl(1,1,2,2,3,3,4,4,4-nonafluorobutylsulfonyl) 159381–10–9
MePFBSAA C7H6F9NO4S Cons < Cons < Cons < No Yes (6) Yes
tanesulfonamidoacetic acid amino]acetic acid
Nonafluoro-3,6-dioxahepta- 2,2-difluoro-2-[1,1,2,2-tetrafluoro-2-(trifluoromethoxy) 151772–58–6
NFDHpA C5HF9O4
noic acid ethoxy]acetic acid
1,1,2,2,3,3,4,4,5,5,6,6,6-Nonafluoro-1-butanesulfona- 30334–69–1
PFBSA Perfluorobutane-sufonamide C4H2F9NO2S Cons < Cons < Cons < No Yes Yes
mide
Perfluoro-3-methoxypropa- 377–73–1
PFMPA C4HF7O3 2,2,3,3-tetrafluoro-3-(trifluoromethoxy)propanoic acid
noic acid
4,8-Dioxa-3H-perfluoronon- 2,2,3-Trifluoro-3-[1,1,2,2,3,3-hexafluoro-3-(trifluo- 919005–14–4
DONA C7H2F12O4 Cons < Cons < Cons < Yes Yes Yes
anoic acid romethoxy)propoxy]propanoic acid
HPFHpA 7H-Perfluoroheptanoic acid C7H2F14O2 2,2,3,3,4,4,5,5,6,6,7,7-Dodecafluoroheptanoic acid 1546–95–8 Cons < Cons < Cons < Yes Yes (7) Yes
Perfluoro-3–7-dimethylocta- 2,2,3,4,4,5,5,6,6,7,8,8,8-Tridecafluoro-3,7-bis(trifluo- 172155–07–6
P37DMOA C10HF19O2 Cons < Cons < Cons < Yes (7) Yes (7) Yes
noic acid romethyl)octanoic acid
Perfluorohexane-sul- 1,1,2,2,3,3,4,4,5,5,6,6,6-tridecafluorohexane-1-sulfon- 41997–13–1
PFHxSA C6H2F13NO2S Cons < Cons < Cons < Yes (7) Yes (6) Yes (5)
fon-amide amide
Perfluoro-4-methoxybuta- 2,2,3,3,4,4-hexafluoro-4-(trifluoromethoxy)butanoic 863090–89–5
PFMBA C5HF9O3
noic acid acid
9-Chlorohexade- 73606–19–6
2-(6-Chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexox-
9Cl-PF3ONS cafluoro-3-oxanonane-1-sul- C8HClF16O4S Cons < Cons < Cons < Yes Yes Yes
y)-1,1,2,2-tetrafluoroethanesulfonic acid
fonic acid
2H,2H,3H,3H-perfluoro unde- 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Heptadecafluoroun- 34598–33–9
4H-PFUnDA C11H5F17O2 Cons < Cons < Yes Yes (6) No Yes
canoic acid decanoic acid
perfluoro-4-ethylcyclohex- 1,2,2,3,3,4,5,5,6,6-decafluoro-4-(1,1,2,2,2-pentafluoro- 646–83–3
4-PFECHS C8HF15O3S Cons < Cons < Cons < Yes (7) Yes (6)
ane sulphonic acid ethyl)cyclohexane-1-sulfonic acid
Perfluoro-2–propoxypropa- 2,3,3,3-Tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropox- 13252–13–6
HFPO-DA C6HF11O3 Cons < Cons < Cons < Yes Yes Yes
noic acid y)-propanoic acid
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

ISO/DIS 25652:2025(en)
2 Normative references
The following documents are referred in the text so that their terms apply in whole or in part to this
document. For dated references, only the cited edition applies. For undated references, the latest edition of
the document (including any change and correction sheets) referenced applies.
EN-ISO 21253-1, Water quality — Multi-compound class methods — Part 1: Criteria for the identification of
target compounds by gas and liquid chromatography and mass spectrometry
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
commonly used international abbreviation for 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- and polyfluoroalkyl substances (PFAS), and per and
polyfluorinated compounds (PFC) as well.
[SOURCE: EN 21675:2019, definition 3.1]
4 Principle
The compounds listed in Table 1 are extracted from the dried, homogenized sample material with methanol,
acetonitrile or a mixture of the two to which isotopically labelled PFAS compounds have been added. 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.
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, PVDF, etc., which are often used in LC equipment, may 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.
ISO/DIS 25652:2025(en)
5.3 Interferences in the HPLC-MS / MS analysis
Peak tailing, peak fronting and/or broadened peaks are indicative of interferences in chromatography.
Sample matrix components can affect the ionization of the target substances. This may 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 may interfere with
the determination. These interferences may 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
may 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.
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 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, e.g. compliant with ISO 3696
6.2 Acetonitrile, CH CN
6.3 Methanol, CH OH
6.4 Sodium Hydroxide, NaOH, alternatively ammonium hydroxide, NH OH, can be used
6.5 Acetic acid, CH COOH, > 96 %
6.6 Ammoniumformate, NH HCO , alternatively ammoniumacetate NH CO CH or ammoniumcarbonate
4 2 4 2 3
(NH ) CO can used
4 2 3
6.7 Extraction solvent, acetonitrile: methanol (1: 1) with 0.05 M 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).
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 M 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 A, ammonium format buffer solution with 5% methanol
Weigh e.g. 1,2 g of ammonium formate (6.6) into a mixture of 3800 ml of water (6.1) and 200 ml of methanol (6.3).

ISO/DIS 25652:2025(en)
6.11 Reference standards
Only use reference standards that consist of at least 95% 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.
NOTE Ampoules of individual isotope labelled standards or mixtures thereof are commercially available.
6.13 Preparation of stock, intermediate and calibration solutions
Calculate the concentration of all reference and calibration solutions on the basis of the dissolved anion
amount. All solutions are stored in the dark at 5 ± 3 °C. The solutions have a shelf life of at least 1 year. The
solutions are brought to room temperature before use. For some compounds sonication and/or vortex 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 (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 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:
— Perfluorated carboxylic acids: PFBA, PFHxA, PFOA, PFDA, PFTeDA, PFODA
— Perfluorated sulfonic acids: PFBS, PFHxS, PFOS, PFDS, PFDoDS
— Fluorotelomers: 4:2 FTS, 10:2 FTS
— Perfluoro-sulfonamides: PFBSA
— Perfluoro-sulfonamide acetic acids: PFOSAA
— Various: DONA, PFECHS, HFPO-DA, PFECHS, 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).
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) at a
concentration of e.g. 0,2 µg / ml.

ISO/DIS 25652:2025(en)
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) with a concentration of e.g. 0,2 µg / ml.
6.13.6 Intermediate solution of reference standards for QC verification calibration curve
Prepare an intermediate solution of the stock solutions of independent reference standards for verification
calibration curve (6.13.3) in methanol (6.3) 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 in increasing concentration prepared in methanol
(6.3) from the intermediate solution of reference standards (6.13.4) with a concentration range of 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
Prepare a spike solution of the intermediate isotope-labelled standards (6.13.5) in methanol (6.3) with a
concentration of e.g. 0,02 µg / ml. The concentration level should be at least 3 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) 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
2)
— SPE adsorption material: Activated carbon, such as Envicarb .
— 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.
2) Envicarb is an example of a suitable product available commercially. This information is given for the convenience of
users of this International Standard and does not constitute an endorsement by ISO of these products.

ISO/DIS 25652:2025(en)
7.1 Sample containers with screw cap, free from background signal
Sample containers made of glass, polypropylene, PET or high-density polyethylene (HDPE) or stainless steel.
7.2 Balance, with read-out accuracy to 0.01 gram
7.3 Syringes
7.4 Test tubes, sampling vials of appropriate volume
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 electrosprayionization (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 within 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 and/or mobile phases, from the target analytes.
8 Sample storage, extraction procedure and analytical analysis preservation
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 or drying at a maximum of 40°C.
Chemical drying (with sodium sulphate) is also a possibility. Pre-treat a field moist soil sample or a sludge
sample in accordance with EN 16179, and waste samples according to EN 15002 or any other suitable
standard.
NOTE 1 Shredding is not necessary if the sample or partial sample has already been freeze-dried.

ISO/DIS 25652:2025(en)
NOTE 2 Drying of the (partial) sample is permitted up to a maximum of 40 °C to minimize loss of volatile PFAS
compounds.
8.3 Extraction
The different steps are summarized in Appendix A Flow chart of sample reprocessing.
Remove 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 is (6.13.8)
added. All samples are shaken briefly by hand to mix the added solutions with the sample.
An amount of acetonitrile (6.2) or methanol (6.3) or a mixture (6.7) of acetonitrile: methanol (1:1) as
extraction solvent with 0,05 M sodium hydroxide or ammonium hydroxide (6.4) are added to all samples in
order to get a L/S 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.
The samples are placed on the shaker (7.8) and shaken for a minimum of 60 minutes. Instead of shaking,
ultrasonication (for a minimum of 60 minutes) may be applied After extraction, the samples are placed in
the centrifuge (7.9) and centrifuged for at least 3 minutes.
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 extract
If needed, a purification step can be applied. The activated carbon purification columns (6.14) are conditioned
with 5 ml of conditioning fluid acetonitrile: methanol: water (1: 1: 1) (6.8). It should be taken into account
that the adsorbent remains wet at all times. Place empty test tubes (7.4) under the purification columns.
Bring e.g. 5 ml of the centrifuged extract (8.3) on the purification columns while still wet and collect the
eluate in the test tubes. Rinse the purification columns with e.g. 6 ml of the eluent acetonitrile: methanol (1:
1) containing 0,05 M acetic acid (6.9) and collect in the same test tube as the eluate.
NOTE The rinse and elution volumes should be optimized depending on the dimensions and / or the type of the
purification column.
The test tubes with purified extract are placed on the evaporation block (7.7). With the aid of a gentle stream
of nitrogen (6.15), the extract is concentrated at a maximum of 55 °C.
Avoid concentration to dryness to avoid loss of volatile compounds.
NOTE Evaporation under inert atmosphere is not mandatory
The final extract is transferred to the vial suitable for HPLC analysis.
The final volume of the extract can be adjusted by diluting with methanol (6.3) depending on the expected
concentration of PFAS. Care should always be taken (by diluting or concentrating) that the concentrations of
the PFAS to be analysed are within the calibration range. There should be a coherence between the choice of
the solvent in the calibration solutions and the final sample. Extracts not directly analysed are stored in the
dark at 5 ± 3 °C during a maximum of 1 week. The stored extracts have to be vortexed before analysis.
8.5 HPLC-MS/MS analysis
Optimize the settings on the HPLC-MS / MS (7.11 to 7.12) for MRM mode under negative ionization using
electro spray. The optimal HPLC program is determined during method development and validation. Due to
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