CEN/TS 15968:2010

Determination of extractable perfluorooctanesulphonate (PFOS) in coated and impregnated solid articles, liquids and fire fighting foams - Method for sampling, extraction and analysis by LC-qMS or LC-tandem/MS

This Technical Specification describes the determination of perfluorooctanesulfonate (PFOS) in concentrated extracts from coated and impregnated solid articles, liquids and fire extinguishing foams using high performance liquid chromatography-tandem mass spectrometry (LC-tandemMS) or quadrupole mass spectrometry (LC-qMS).
The method is applicable for a concentration range for PFOS in the extract solution of 0,5 µg/l to 50 µg/l.
WARNING - Persons using this Technical Specification should be familiar with normal laboratory practice. This Technical Specification 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 and to ensure compliance with any national regulatory conditions.
IMPORTANT - It is absolutely essential that tests conducted in accordance with this Technical Specification be carried out by suitably qualified staff.

Bestimmung von extrahierbarem Perfluoroctansulfonat (PFOS) in beschichteten und imprägnierten Feststoffartikeln, Flüssigkeiten und Feuerlöschschäumen - Verfahren zur Probenahme, Extraktion und Analyse mittels LC-MS oder LC-MS

Die vorliegende Technische Spezifikation beschreibt die Bestimmung von Perfluoroctansulfo¬nat (PFOS) in konzentrierten Extrakten aus beschichteten und imprägnierten Feststoffartikeln, Flüssigkeiten und Feuerlöschschäumen unter Anwendung von Hochleistungs-Flüssigkeitschromatographie/Tandem-Massen-spektrometrie (LC tandem/MS) oder Quadrupol-Massenspektrometrie (LC qMS).
Das Verfahren ist anwendbar auf Konzentrationen von PFOS in der Extraktionslösung im Bereich zwischen 0,5 µg/l und 50 µg/l.
WARNUNG - Die Anwender dieser Technischen Spezifikation sollten mit der üblichen Laborpraxis vertraut sein. Diese Technische Spezifikation beansprucht nicht, sämtliche mit deren Anwendung verbundenen Sicherheitsprobleme, soweit solche gegeben sind, abzudecken. Es liegt in der Verantwortung des Anwenders, geeignete Maßnahmen für Gesundheits- und Arbeitsschutz einzuleiten und deren Übereinstimmung mit sämtlichen nationalen gesetzlichen Vorschriften sicherzustellen.
WICHTIG - Es ist unbedingt notwendig, dass Prüfungen nach dieser Technischen Spezifikation von entspre¬chend qualifizierten Personen durchgeführt werden.

Détermination du sulfonate de perfluorooctane (SPFO) extractible dans des articles solides couchés et imprégnés, des liquides et des mousses anti-incendie - Méthode d'échantillonnage, d'extraction et d'analyse par LC-MS ou LC-MS/MS

La présente Spécification technique européenne décrit la détermination du sulfonate de perfluorooctane (SPFO) dans un extrait concentré provenant d’articles solides couchés et imprégnés, de liquides et de mousses anti-incendie au moyen d’une chromatographie en phase liquide haute performance couplée à la spectrométrie de masse en tandem (LC-MS/MS) ou à une spectrométrie de masse quadripôle (LC-MS).
La méthode est applicable pour une plage de concentration de SPFO dans la solution d’extrait allant de 0,5 ng/ml à 50 ng/ml.
AVERTISSEMENT — Il convient que les utilisateurs de la présente Spécification technique soient familiarisés avec les pratiques courantes de laboratoire. La présente Spécification technique n’a pas pour objet de traiter tous les problèmes de sécurité qui sont, le cas échéant, liés à son utilisation. Il incombe à l’utilisateur d’établir des pratiques appropriées en matière d’hygiène et de sécurité et de s'assurer de la conformité à la réglementation nationale en vigueur.
IMPORTANT — Il est absolument essentiel que les essais menés conformément à la présente Spécification technique soient effectués par un personnel qualifié.

Določevanje izločljivega perfluorooktansulfonata (PFOS) v prevlečenih in impregniranih trdnih predmetih, tekočinah in protipožarnih penah - Metode vzorčenja, ekstrakcije in analize s pomočjo LC-MS ali LC-MS/MS

Ta tehnična specifikacija opisuje določevanje perfluorooktansulfonata (PFOS) v koncentriranih ekstraktih iz prevlečenih in impregniranih trdnih predmetov, tekočin in protipožarnih pen z uporabo tekočinske kromatografije visoke ločljivosti LC-MS ali LC-MS/MS. Metoda se uporablja za razpon koncentracije PFOS v raztopini ekstrakta od 0,5 μg/l do 50 μg/l.

General Information

• Status: Withdrawn
• Publication Date: 10-Aug-2010
• Withdrawal Date: 13-Apr-2025
• ICS: 71.040.50 - Physicochemical methods of analysis
• ICS: 71.080.20 - Halogenated hydrocarbons
• Technical Committee: CEN/TC 248 - Textiles and textile products
• Drafting Committee: CEN/TC 382 - Project Committee - PFOS
• Current Stage: 9960 - Withdrawal effective - Withdrawal
• Start Date: 22-Nov-2023
• Completion Date: 14-Apr-2025
• Mandate: M/402 - Mandates for standardisation addressed to CEN for methods of analysis to detect perfluorooctane sulphonates in preparations, semifinished products and articles including textile and coated materials,
• Ref Project: SIST-TS CEN/TS 15968:2010 - Determination of extractable perfluorooctanesulphonate (PFOS) in coated and impregnated solid articles, liquids and fire fighting foams - Method for sampling, extraction and analysis by LC-qMS or LC-tandem/MS

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2010
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Determination of extractable perfluorooctanesulphonate (PFOS) in coated and
impregnated solid articles, liquids and fire fighting foams - Method for sampling,
extraction and analysis by LC-qMS or LC-tandem/MS
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Détermination du sulfonate de perfluorooctane (SPFO) extractible dans des articles
solides couchés et imprégnés, des liquides et des mousses anti-incendie - Méthode
d'échantillonnage, d'extraction et d'analyse par LC-MS ou LC-MS/MS
Ta slovenski standard je istoveten z: CEN/TS 15968:2010
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
71.080.20 Halogenirani ogljikovodiki Halogenated hydrocarbons
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 15968
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
August 2010
ICS 71.040.50; 71.080.20
English Version
Determination of extractable perfluorooctanesulphonate (PFOS)
in coated and impregnated solid articles, liquids and fire fighting
foams - Method for sampling, extraction and analysis by LC-
qMS or LC-tandem/MS
Détermination du sulfonate de perfluorooctane (SPFO) Bestimmung von extrahierbarem Perfluoroctansulfonat
extractible dans des articles solides couchés et imprégnés,
(PFOS) in beschichteten und imprägnierten
des liquides et des mousses anti-incendie - Méthode Feststoffartikeln, Flüssigkeiten und Feuerlöschschäumen -
d'échantillonnage, d'extraction et d'analyse par LC-MS ou Verfahren zur Probenahme, Extraktion und Analyse mittels
LC-MS/MS LC-MS oder LC-MS
This Technical Specification (CEN/TS) was approved by CEN on 25 October 2009 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15968:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Symbols and abbreviations .7
5 Principle .7
6 Apparatus and Reagents .8
6.1 General .8
6.2 Equipment .9
6.3 Reagents for extraction .9
6.4 Reagents for LC and MS .9
7 Sampling . 10
7.1 General . 10
7.2 Conditioning samples . 10
7.3 Sampling solids . 10
7.4 Sampling products that have separate distinct parts . 10
7.5 Sampling liquids . 10
8 Sample pre-treatment . 11
9 Extraction . 11
9.1 Extraction method for textile, fabrics, leather and paper . 11
9.2 Clean-up method for textile, fabrics, leather and paper . 11
9.3 Dilution method for aqueous fire extinguishing foams . 11
9.4 Extraction method for other liquids . 12
10 Interference with LC-tandemMS . 12
11 Analysis . 12
11.1 LC-tandemMS operating conditions . 12
11.2 Blank determination . 12
11.3 Quality Control samples . 12
11.4 Identification . 12
12 System suitability test . 14
12.1 Calibration . 14
12.2 Recovery . 15
12.3 Blank measurement . 15
13 Calculation . 15
13.1 Calibration curve for quantification . 15
13.2 Calculation of results after calibration with reference compounds . 16
13.3 Calculation of results to PFOS equivalents . 17
14 Expression of results . 17
15 Test report . 18
Annex A (informative) LC-QMS and LC-TOFMS . 20
Annex B (informative) . 25
Annex C (informative) Confirmation of compound identity by MS methods . 26
Bibliography . 31

Foreword
This document (CEN/TS 15968:2010) has been prepared by Technical Committee CEN/TC 382 “Project
Committee - PFOS”, the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association and supports essential requirements of REACH (1907/2006), annex XVII,
designation 53 [1].
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
Introduction
For implementation of REACH (1907/2006), annex XVII, designation 53 [1] the European Commission asked
CEN to develop an European Technical Specification with test methods for measuring levels of PFOS
containing compounds in preparations, semi-finished products and articles including textile and coated
materials.
REACH (1907/2006), annex XVII, designation 53 [1] states that the substances that are under the Directive
are perfluorooctanesulfonates (PFOS), that means substances with the formula C F SO X (where X=OH,
8 17 2
Metal salt (O-M+), halide, amide and other derivatives including polymers).

1 Scope
This Technical Specification describes the determination of perfluorooctanesulfonate (PFOS) in concentrated
extracts from coated and impregnated solid articles, liquids and fire extinguishing foams using high
performance liquid chromatography-tandem mass spectrometry (LC-tandemMS) or quadrupole mass
spectrometry (LC-qMS).
The method is applicable for a concentration range for PFOS in the extract solution of 0,5 µg/l to 50 µg/l.
WARNING ― Persons using this Technical Specification should be familiar with normal laboratory
practice. This Technical Specification 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 and to ensure compliance with any national regulatory conditions.
IMPORTANT ― It is absolutely essential that tests conducted in accordance with this Technical
Specification be carried out by suitably qualified staff.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 20187, Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for
monitoring the atmosphere and conditioning of samples (ISO 187:1990)
EN ISO 2419, Leather — Physical and mechanical tests — Sample preparation and conditioning
(ISO 2419:2006)
EN ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987)
EN ISO 8130-9, Coating powders — Part 9: Sampling (ISO 8130-9:1992)
EN ISO 15194, In vitro diagnostic medical devices — Measurement of quantities in samples of biological
origin ― Requirements for certified reference materials and the content of supporting documentation
(ISO 15194:2009)
ISO 8466-1, Water quality — Calibration and evaluation of analytical methods and estimation of performance
characteristics — Part 1: Statistical evaluation of the linear calibration function
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply
3.1
analyte
substance or chemical constituent that is subjected to measurement
3.2
blank matrix
matrix which is largely identical with the analytical one, but does not contain the analyte or contains it in low
and known content
NOTE Blanks are used to check the analytical process.
3.3
constituents
all pure chemical materials and substances of which a material is composed
3.4
extract
concentrated preparation of the analytes isolated from the treated material
3.5
foams
fire extinguishing foams
3.6
overall treated materials
materials with a seamless finish
3.7
internal standard
compound different from the analyte, present in the sample with known content or added to the sample,
simultaneously detected with the analyte, with physical and chemical properties as similar as possible to the
analyte
3.8
reference material
RM
material, sufficiently homogeneous and stable regarding one or more properties, used in calibration,
assignment of a value to another material, or quality assurance (conform EN ISO 15194)
3.9
coated materials
materials that are treated with chemicals to provide them with water and soil repellent properties; or treated for
aesthetic or decorative reasons
4 Symbols and abbreviations
LC-qMS  liquid chromatography (LC) coupled with quadrupole mass spectrometry (qMS)
LC-tandemMS liquid chromatography (LC) coupled with tandem mass spectrometry (tandemMS)
LC-TOFMS liquid chromatography (LC) coupled with time of flight mass spectrometer (TOFMS)
5 Principle
The analytes listed in Table 1, after extraction with methanol, are determined by liquid chromatography with
tandem mass spectrometric detection (LC-tandemMS) or liquid chromatography mass spectrometric detection
(LC-qMS). The list of analytes is not comprehensive for all possible PFOS derivates.
Table 1 — Analytes determinable by this method
Compound name Chemical formula Acronym CAS No.
Perfluorooctane sulphonic C8F17SO3H PFOS  1763-23-1
acid
Perfluorooctane C8F17SO2NH2 PFOSA 754-91-6
sulphonamide
a
N-Methyl- C8F17SO2NH(CH3) N-Me-FOSA N.A.
heptadecafluorooctane
sulphonamide
a
N-Ethyl- C8F17SO2NH(C2H5) N-Et-FOSA N.A.
heptadecafluorooctane
sulphonamide
N-Methyl- C8F17SO2N(CH3)CH2CH2OH N-Me-FOSE alcohol 24448-09-7
heptadecafluorooctane
sulphonamidoethanol
N-Ethyl- C8F17SO2N(C2H5)CH2CH2OH N-Et-FOSE alcohol 1691-99-2
heptadecafluorooctane
sulphonamidoethanol
NOTE PFOS may be present in its salt form e.g. potassium salt (CAS 2795-39-3), lithium salt (CAS 29457-72-5), ammonium
salt (CAS 29081-56-9) and diethanolamine salt (CAS 70225-39-5). Others may exist. The method described in this protocol is
valid for all these different chemical forms.
a
N.A.: Not available.
This Technical Specification describes the method for determining the PFOS concentration in the following
steps:
a) sampling (see Clause 7);
b) extraction with methanol (see Clause 9);
c) clean up of the methanol solution (see 9.2);
d) analysis by LC-qMS or LC-tandemMS (see Clause 11);
e) calculation of the results (see Clause 13).
6 Apparatus and Reagents
6.1 General
Sample containers shall be rinsed thoroughly with water (0) and methanol (0) prior to use. Sample containers
shall be checked for possible background contamination before use.
Equipment or any accessible part of which that may come into contact with the sample or the extract should
be free from interfering compounds.
Clean all lab-ware and accessible parts of apparatus for extraction by rinsing with methanol (0).
6.2 Equipment
Use equipment free from glass (e.g. PP, PE):
 cutting die or template and cutting tool to measure and cut area materials (textiles, leather, paper, etc.).
Mill to grind granular bulk solids;
 125 µm sieve;
 volumetric flasks, with inert stopper;
 vials, polypropylene or polyethylene;
 ultrasonic bath, equipped with adjustable and stable bath temperature (20 °C to 70 °C);
 concentration equipment (e.g. hydrophilic lipophilic base, SPE, weak anion exchange resin or rotavapor);
 high performance liquid chromatograph, temperature-controlled and with all required accessories
including gases, LC columns, injector and a mass spectrometric detector either tandemMS or qMS.
Alternative methods e.g. LC-/TOFMS are discussed in Annex A.
6.3 Reagents for extraction
6.3.1 Methanol, CH OH (ultra pure).
6.4 Reagents for LC and MS
6.4.1 Water, complying with at least grade 3 as specified in EN ISO 3696:1995, also applicable for blank
determinations.
6.4.2 Acetic Acid, w(CH COOH) ≥ 99,9 %.
COONH ) ≥ 97 %.
6.4.3 Ammonium acetate, w(CH
3 4
6.4.4 Formic Acid, w(HCOOH) ≥ 99 %.
6.4.5 Methanol, CH OH (HPLC grade).
6.4.6 Gases for MS.
 Nitrogen, GC grade 5.0 or better;
 Collision gas (e.g. Argon);
 Helium, GC grade 5.0 or better.
6.4.7 Reference solutions.
13 - + 13
 C -PFOS (e.g. [F(CF ) SO H ]-, 1,2,3,4- C ); or
x 2 8 3 4
18 - + 18
 O PFOS (e.g. [F(CF ) SO H ]-, O ).
x- 2 8 3 2
In addition, when other types of labelled internal standards become available, they may be used.
Solutions of the reference compounds are available commercially. They should be diluted to required
concentrations.
If reference compounds are obtained as neat, weigh 100 mg of each standard separately into a 100 ml
volumetric flask and make up to the mark with methanol. Dilute this solution with methanol at a ratio 1:1 000.
The impurity levels of the internal standards should be determined prior to the use of new of every new lot.
6.4.8 Range of calibration solutions, in concentration range 0,5 µg/l to 50 µg/l.
7 Sampling
7.1 General
The chosen sample should be representative for the lot it is taken from. This document describes two different
ways of reporting results which require two different ways of sample collection. One way is based on the
content per area (mass/area). The other way is based on content per mass (mass/percentage).
7.2 Conditioning samples
Materials and samples shall be stored preferably at 4 °C and in clean containers, see 6.2, before testing.
Conditioning of leather shall be done according to EN ISO 2419.
Conditioning of paper shall be done according to EN 20187.
7.3 Sampling solids
7.3.1 Coated materials like paper, textile, leather, carpets, clothes and footwear
If applicable take a sample of at least 200 cm using a cutting die or any other suitable tool and template;
weigh the sample to make sure results can be reported as well in percentage/weight as in micrograms per
square metre.
NOTE Make sure that the sample is not stretched (be aware that crinkled materials can easily have a much higher
surface area).
If the material is not suitable to provide area-based samples, take a sample by weight, using at least 2 g of
material.
7.3.2 Non-coated materials
Powders, granulates and other bulk materials shall be sampled according to EN ISO 8130-9.
For any other material an appropriate representative amount of the product shall be cut off, see 7.3.1.
7.4 Sampling products that have separate distinct parts
Products consisting of separate distinctive parts shall be dismounted and each part shall be treated according
to 7.3.1.
7.5 Sampling liquids
The samples for testing shall be taken and delivered by the supplier using a method which will provide a
representative sample of the liquid to be tested.
8 Sample pre-treatment
Sample materials need to ground as appropriate to ensure an efficient extraction process.
Leather materials shall be cut in pieces of maximum 25 mm .
Textile and paper shall be cut into pieces of maximum 1 cm before methanol is added.
For grinding of polymers and granulates it is recommended to use EN ISO 6427 [2] or ISO 9113 [3].
9 Extraction
9.1 Extraction method for textile, fabrics, leather and paper
a) Place the sample in a closed container to avoid loss of solvent through evaporation.
b) Add a suitable quantity of labelled internal standard solution.
c) Equilibrate the sample for at least 1 h.
d) Add 50 ml methanol or as much as is needed to cover the treated material.
e) Place in an ultrasonic bath for 2 h at 60 °C.
9.2 Clean-up method for textile, fabrics, leather and paper
Co-extracted materials can interfere in the determination by LC-tandemMS and LC-qMS. These can include
e.g. natural lipids from leather. Their influence should be minimised to obtain accurate results.
Clean up of the methanol extract and preparation of the test:
a) Concentrate the extract by a factor of 10 and use a clean-up if necessary.
NOTE Active carbon clean-up and/or solid phase extraction (SPE) clean-up may be used.
b) Transfer a known volume into a suitable LC sampling vial and perform LC-qMS analysis according to
Clause 11.
c) If necessary dilute the original solution further and repeat the analysis.
9.3 Dilution method for aqueous fire extinguishing foams
The sample should be equilibrated at room temperature (20 ± 5) °C before any solutions or analyses are
performed. Homogenise the sample and make up dilutions as follows:
a) Pre-dilute the sample in separate steps with purified water or methanol (1:10 v/v, 1:100 v/v, 1:1 000 v/v)
and mix sufficiently (e.g. 500 µl sample into 4 500 µl diluent).
b) Ensure that there is no phase-separation in the sample.
c) If necessary centrifuge the sample to precipitate non soluble particles.
d) Dilute the pre-diluted sample 1:10 with water or methanol and an appropriate volume of internal standard
solution (e.g. 100 µl diluted sample, 100 µl reference solution, 800 µl water or methanol) to have in every
dilution (1:10 v/v, 1:100 v/v, 1:1 000 v/v) the same concentration of the internal standard.
e) Transfer an aliquot to a LC vial and analyse the sample. If high PFOS concentrations are expected, begin
with the highest dilution (1:10 000 v/v) to avoid a carry over.
NOTE 1 The dilution error introduced by this method should be much smaller than the analytical error involved in the
method. As a general rule the dilution error should be less than 1 %.
NOTE 2 If it is possible and necessary a dilution of 1:10 v/v or a direct injection of the sample with internal standard
solution is allowed.
9.4 Extraction method for other liquids
There is no best practice method available for the extraction of other liquids which cannot be extracted with
SPE. The method in 9.3 may be used as an example for the extraction of other liquids.
NOTE ISO 25101 [4] describes a method for the determination of PFOS in unfiltered samples of drinking water,
ground water and surface water.
10 Interference with LC-tandemMS
Substances with similar retention times and similar fragment masses when compared with the analytes of
interest can interfere with the determination.
These interferences can lead to incompletely resolved signals and additional signals in the chromatographic
pattern of target analytes. They can, depending on their levels in the sample, affect the accuracy and
precision of the analytical results.
Matrix interferences can be caused by contaminants that are co-extracted from the samples. The extent of
matrix interferences varies considerably, depending on the nature of the samples.
11 Analysis
11.1 LC-tandemMS operating conditions
Optimise the operating conditions of the LC-tandemMS system in electrospray ionization (ESI) negative mode
in accordance with the manufacturer's instructions. The appropriate LC gradient programme for mobile phase
is determined experimentally during method development and validation. For optimum sensitivity, selected
ions for MS/MS transitions are listed in Table 2. Examples of the operating conditions for various MS systems
are given in Annex A.
11.2 Blank determination
Treat the blank in exactly the same way as the samples, except that the analyte is absent. After a maximum of
ten samples of one batch at least one blank should be analysed.
11.3 Quality Control samples
Analyse the Quality Control (QC) samples (procedural blank and spiked matrix sample) for each batch of
samples to ensure accuracy and reliability of the analytical process. Samples spiked with internal standard
solutions should be analysed according to 9.1.
11.4 Identification
For confirmation of the identity of the analytes, the detection method should comply with the European
Commission Decision 2002/657/EC [5]. PFOS and related compounds fall under group B of the Annex 1 of
the above-mentioned EC Decision, which concerns veterinary drugs and contaminants. Hence, the number of
identification points required would be 3, and therefore LC-tandemMS (triple quad) using two transition
products, or LC-qMS (single quad) using three ions typically qualify for the confirmation of PFOS, see also
Annex C.
NOTE 1 The determination of the accurate mass (e.g. with Time of Flight MS) can be used for a confirmation of a
positive result.
Identify the sample component by matching both retention times and relative intensities of the monitored ions
(Table 2) of the sample components and the reference substances.
The target compound is present (identified) in the sample if the relative or the absolute sample component
retention time measured in the mass chromatogram matches the relative or the absolute retention time of the
authentic compound within ± 0,2 % in the chromatogram of the latest calibration standard, measured under
identical conditions.
The manufacture of PFOS results in a product that generally contains both the linear and the branched
isomers. Therefore PFOS when analysed does not appear as a single peak, but rather as a number of peaks
in the mass chromatograms. Branched isomers can co-elute as a single peak, but the linear (n-octyl) isomer
can be separated from others using specific chromatography colu
...