ISO 21675:2019

INTERNATIONAL ISO
STANDARD 21675
First edition
2019-10
Water quality — Determination of
perfluoroalkyl and polyfluoroalkyl
substances (PFAS) in water — Method
using solid phase extraction and
liquid chromatography-tandem mass
spectrometry (LC-MS/MS)
Qualité de l'eau — Détermination des substances d'alkyle perfluorés
et polyfluorés (SPFA) dans l'eau — Méthode par extraction en phase
solide et chromatographie liquide et spectrométrie de masse en
tandem (CL-SM/SM)
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Interferences . 3
5.1 Interferences with sampling and extraction . 3
5.2 Interferences with LC-MS/MS. 4
6 Reagents . 4
7 Apparatus . 7
8 Sampling . 8
9 Procedure. 8
9.1 Solid-phase extraction . 8
9.1.1 General. 8
9.1.2 Sample preparation . 8
9.1.3 Conditioning of the solid-phase extraction material . 9
9.1.4 Sample extraction . 9
9.1.5 Elution . 9
9.2 LC-MS/MS operating conditions .10
9.3 Blank determination .12
9.4 Identification .12
10 Calibration .13
10.1 General requirements .13
10.2 Calibration using an external standard .13
10.3 Calibration using an internal standard .14
11 Calculation .15
11.1 Use of a calibration curve to determine concentration .15
11.2 Calculation of concentration using calibration with external standards .15
11.3 Calculation of concentration using calibration with internal standards .16
11.4 Treatment of results outside the calibration range .16
12 Determination of analyte recovery .16
12.1 Recovery .16
12.2 Recovery of internal standards .17
13 Expression of results .18
14 Test report .18
Annex A (informative) Examples of suitable sorbents .19
Annex B (informative) Examples of suitable LC columns .20
Annex C (informative) Examples of suitable LC-MS/MS conditions .21
Annex D (normative) Filtration and extraction of suspended matter in the sample .25
Annex E (informative) Examples of chromatographic separation of individual linear and
branched PFAS isomers .27
Annex F (informative) Rapid method by direct injection .31
Annex G (informative) Rapid method by online solid phase extraction LC-MS/MS .32
Annex H (informative) Performance data by DIN 38407-42 for selected PFAS .35
Annex I (informative) Performance data .37
Bibliography .43
iv © ISO 2019 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2,
Physical, chemical and biochemical methods.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
INTERNATIONAL STANDARD ISO 21675:2019(E)
Water quality — Determination of perfluoroalkyl and
polyfluoroalkyl substances (PFAS) in water — Method
using solid phase extraction and liquid chromatography-
tandem mass spectrometry (LC-MS/MS)
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 the determination of selected perfluoroalkyl and polyfluoroalkyl
substances (PFAS) in non-filtrated waters, for example drinking water, natural water (fresh water and
sea water) and waste water containing less than 2 g/l solid particulate material (SPM) using liquid
chromatography-tandem mass spectrometry (LC-MS/MS). The compounds monitored by this method
are typically the linear isomers. The group of compounds determined by this method are representative
of a wide variety of PFAS. The analytes specified in Table 1 can be determined by this method. The list
can be modified depending on the purpose for which the method is intended. The lower application
range of this method can vary depending on the sensitivity of the equipment used and the matrix of the
sample. For most compounds to which this document applies ≥0,2 ng/l as limit of quantification can be
achieved. Actual levels can depend on the blank levels realized by individual laboratory.
The applicability of the method to further substances, not listed in Table 1, or to further types of water
is not excluded, but is intended to be validated separately for each individual case.
NOTE 1 PFAS is used in this document to describe the analytes monitored. Many of the compounds in Table 1
are perfluoroalkyl and are also considered polyfluoroalkyl substances.
NOTE 2 The linear PFAS isomers are specified in this document. The branched isomers can be present in
environmental samples, especially for PFOS. Annex E provides an example of an analytical approach to the
chromatographic and spectroscopic separation of individual isomers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only
...

INTERNATIONAL ISO
STANDARD 21675
First edition
2019-10
Water quality — Determination of
perfluoroalkyl and polyfluoroalkyl
substances (PFAS) in water — Method
using solid phase extraction and
liquid chromatography-tandem mass
spectrometry (LC-MS/MS)
Qualité de l'eau — Détermination des substances d'alkyle perfluorés
et polyfluorés (SPFA) dans l'eau — Méthode par extraction en phase
solide et chromatographie liquide et spectrométrie de masse en
tandem (CL-SM/SM)
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Interferences . 3
5.1 Interferences with sampling and extraction . 3
5.2 Interferences with LC-MS/MS. 4
6 Reagents . 4
7 Apparatus . 7
8 Sampling . 8
9 Procedure. 8
9.1 Solid-phase extraction . 8
9.1.1 General. 8
9.1.2 Sample preparation . 8
9.1.3 Conditioning of the solid-phase extraction material . 9
9.1.4 Sample extraction . 9
9.1.5 Elution . 9
9.2 LC-MS/MS operating conditions .10
9.3 Blank determination .12
9.4 Identification .12
10 Calibration .13
10.1 General requirements .13
10.2 Calibration using an external standard .13
10.3 Calibration using an internal standard .14
11 Calculation .15
11.1 Use of a calibration curve to determine concentration .15
11.2 Calculation of concentration using calibration with external standards .15
11.3 Calculation of concentration using calibration with internal standards .16
11.4 Treatment of results outside the calibration range .16
12 Determination of analyte recovery .16
12.1 Recovery .16
12.2 Recovery of internal standards .17
13 Expression of results .18
14 Test report .18
Annex A (informative) Examples of suitable sorbents .19
Annex B (informative) Examples of suitable LC columns .20
Annex C (informative) Examples of suitable LC-MS/MS conditions .21
Annex D (normative) Filtration and extraction of suspended matter in the sample .25
Annex E (informative) Examples of chromatographic separation of individual linear and
branched PFAS isomers .27
Annex F (informative) Rapid method by direct injection .31
Annex G (informative) Rapid method by online solid phase extraction LC-MS/MS .32
Annex H (informative) Performance data by DIN 38407-42 for selected PFAS .35
Annex I (informative) Performance data .37
Bibliography .43
iv © ISO 2019 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2,
Physical, chemical and biochemical methods.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
INTERNATIONAL STANDARD ISO 21675:2019(E)
Water quality — Determination of perfluoroalkyl and
polyfluoroalkyl substances (PFAS) in water — Method
using solid phase extraction and liquid chromatography-
tandem mass spectrometry (LC-MS/MS)
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 the determination of selected perfluoroalkyl and polyfluoroalkyl
substances (PFAS) in non-filtrated waters, for example drinking water, natural water (fresh water and
sea water) and waste water containing less than 2 g/l solid particulate material (SPM) using liquid
chromatography-tandem mass spectrometry (LC-MS/MS). The compounds monitored by this method
are typically the linear isomers. The group of compounds determined by this method are representative
of a wide variety of PFAS. The analytes specified in Table 1 can be determined by this method. The list
can be modified depending on the purpose for which the method is intended. The lower application
range of this method can vary depending on the sensitivity of the equipment used and the matrix of the
sample. For most compounds to which this document applies ≥0,2 ng/l as limit of quantification can be
achieved. Actual levels can depend on the blank levels realized by individual laboratory.
The applicability of the method to further substances, not listed in Table 1, or to further types of water
is not excluded, but is intended to be validated separately for each individual case.
NOTE 1 PFAS is used in this document to describe the analytes monitored. Many of the compounds in Table 1
are perfluoroalkyl and are also considered polyfluoroalkyl substances.
NOTE 2 The linear PFAS isomers are specified in this document. The branched isomers can be present in
environmental samples, especially for PFOS. Annex E provides an example of an analytical approach to the
chromatographic and spectroscopic separation of individual isomers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only
...