SIST EN ISO 787-28:2020

SLOVENSKI STANDARD
oSIST prEN ISO 787-28:2020
01-junij-2020
Splošne metode preskušanja pigmentov in polnil - 28. del: Določevanje celotnih
polikloriranih bifenilov (PCB) z raztapljanjem, čiščenjem in plinsko kromatografijo
z masno selektivnim detektorjem (GC-MS) (ISO 787-28:2019)
General methods of tests for pigments and extenders - Part 28: Determination of total
content of polychlorinated biphenyls (PCB) by dissolution, cleanup and GC-MS (ISO 787
-28:2019)
Allgemeine Prüfverfahren für Pigmente und Füllstoffe - Teil 28: Bestimmung des
Gesamtgehalts an polychlorierten Biphenylen in organischen Pigmenten durch
Auflösung, Reinigung und GC/MS (ISO 787-28:2019)
Méthodes générales d'essai des pigments et matières de charge - Partie 28:
Détermination de la teneur totale en biphényles polychlorés dans les pigments
organiques par dissolution, purification et CG-SM (ISO 787-28:2019)
Ta slovenski standard je istoveten z: prEN ISO 787-28
ICS:
87.060.10 Pigmenti in polnila Pigments and extenders
oSIST prEN ISO 787-28:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 787-28:2020

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oSIST prEN ISO 787-28:2020
INTERNATIONAL ISO
STANDARD 787-28
First edition
2019-05
General methods of tests for pigments
and extenders —
Part 28:
Determination of total content of
polychlorinated biphenyls (PCB) by
dissolution, cleanup and GC-MS
Méthodes générales d'essai des pigments et matières de charge —
Partie 28: Détermination de la teneur totale en biphényles polychlorés
dans les pigments organiques par dissolution, purification et CG-SM
Reference number
ISO 787-28:2019(E)
©
ISO 2019

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oSIST prEN ISO 787-28:2020
ISO 787-28:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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
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Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Sampling . 2
6 Procedure. 2
6.1 General . 2
6.2 Clean-up to eliminate interfering species . 3
6.3 Separation and quantification . 3
7 Reagents . 3
7.1 Safety precautions . 3
7.2 Reagents, solvents and absorbents. 4
7.3 Internal reference materials for PCBs, 13C12-labelled . 5
7.4 Cleaning/disposal agents . 5
8 Apparatus . 5
9 Procedure. 6
9.1 Preparation of test sample . 6
9.2 Liquid-liquid extraction . 7
9.2.1 Separation funnel . 7
9.2.2 Ludwig extraction . 8
9.3 Clean-up . 8
9.3.1 General. 8
9.3.2 Diatomaceous earth-sulfuric acid column (optional) . 8
9.3.3 Gel permeation (size exclusion) chromatography/porous styrene
divinylbenzene beads-column (optional) . 9
9.3.4 Multilayer columns (obligatory) .10
9.3.5 Alumina column (optional) .11
9.4 Preparation of GC solution and GC procedure .11
9.5 Calculation and quantitation procedure .12
10 Test report .14
Annex A (informative) Nomenclature of PCBs .15
Bibliography .21
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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 on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 256, Pigments, dyestuffs and extenders.
A list of all parts in the ISO 787 series can be found on the ISO website.
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 https: //www .iso .org/members .html.
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Introduction
A number of methods to quantify PCBs in “environmental samples” or oil residues prove inadequate for
pigments due to being merely extractive on the particle surface without taking into account occlusions
of contaminants in the crystal lattice of pigments (see References [1] to [3]).
Occurrence and formation principles are referred to in References [5], [6] and [8].
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oSIST prEN ISO 787-28:2020
INTERNATIONAL STANDARD ISO 787-28:2019(E)
General methods of tests for pigments and extenders —
Part 28:
Determination of total content of polychlorinated
biphenyls (PCB) by dissolution, cleanup and GC-MS
1 Scope
This document specifies a method for determining the total content of polychlorinated biphenyls
(PCBs), checking for all 209 possible congeners in pigment materials.
This document is applicable to a working range from1 mg/kg to 150 mg/kg. The lower quantitation limit
of this method is 1 mg/kg per congener. Results below 1 mg/kg are considered to be qualitative only.
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 the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
ISO 18451-1, Pigments, dyestuffs and extenders — Terminology — Part 1: General terms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18451-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
polychlorinated biphenyls
PCB
209 congeners, from mono- through deca-chlorinated biphenyls, which may be subdivided into homologue
groups comprising PCB congeners with the same degree of chlorination, i.e. same gross formula
Note 1 to entry: The general CAS-Number for polychlorinated biphenyls is 1336-36-3. For a comprehensive
congener list with CAS-Numbers, see Annex A or Reference [5].
3.2
internal reference material
13
mixture of defined quantities of C-Isotope-labelled PCBs added directly into the freshly weighed
pigment sample
Note 1 to entry: No subsequent additions of internal reference materials are permitted. Surrogate standards
reference materials can be added to assess recovery rates only, but these cannot be deemed an internal reference
materials, nor can these be used for quantitation.
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Note 2 to entry: Mass spectrometry assumes a vast linear range of detector sensitivity, thus a calibration with a
single quantity will usually suffice.
Note 3 to entry: In case of major deviations between analytes and reference material concentrations, the
quantitation might need to be confirmed by a second analysis (from the beginning) using an adequately adapted
sample weight.
4 Principle
The principles have been developed from References [1] to [4], [6] and [7].
The use of solid surface extraction methods risks underestimating the actual content by orders of
magnitude. Such errors are often further enhanced when the PCBs quantitation is carried out by using
external or internal reference materials which do not undergo the same losses as the analytes that are
occluded in the crystal lattice of the pigment.
5 Sampling
Take a representative sample of the product to be tested, as described in ISO 15528.
Samples shall be of dry powder consistency. Volatiles should be less than 1 % (mass fraction),
determined with a sample portion separated from the sample portions used for PCB analyses.
Samples shall be kept in the dark and in capped glass bottles or vials.
Samples suspected of having high impurities content shall be handled in dedicated glassware and
kept separately from other laboratory equipment; sample mass may be reduced and internal reference
materials amounts doubled in order to cope with the possible elevated levels of interferences by
impurities. A screening pre-run is recommended to avoid detector overload.
Bromine detection or presence of partially brominated samples (e.g. C.I. Pigment Red 168, C.I. Pigment
Green 36) require caution due to occurrence of “mixed” halogenated aromatic compounds. Analysis can
proceed if results are checked for non-interference (see 9.5).
6 Procedure
6.1 General
This method requires a strict sequential application of the following steps:
— sample weighing;
— addition of internal reference material and thorough mixing;
— dissolution in concentrated sulfuric acid from 92 % (mass fraction) to 95 % (mass fraction);
— sonicate the mixture until fully dissolved and a homogenous dark solution is obtained in the
sulfuric acid phase. The temperature shall be kept lower than 50 °C at all times, e.g. by circulating
or continuously exchanging the water in the sonication bath.
NOTE 1 Using this concentration range avoids major disintegration and rearrangement of mono- and
bichlorinated biphenyls.
NOTE 2 Sufficient dissolution is indicated by absence of the “tyndall-effect” (i.e. no scattering of a preferably
blue light beam by the solution).
Upon dissolution in concentrated sulphuric acid, pigment molecules are protonated and may be
considered in a simplified way as being pulled out of their crystal lattice one by one in drawer-
like fashion, until all the solid matter has dissolved, without cleavage occurring at the molecular
(chromophor) level.
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Any possible inadvertent destruction of analytes is likely to occur also to the internal reference
materials at a related, nearly equal rate, thus compensating for any destructive effects, at the expense
of a slightly lower signal-to-noise ratio (see Reference [5]). There maybe a slightly increased rate of
destruction for low chlorinated biphenyls.
This may be offset by a preceding leaching step as described in the Note to 9.1.
6.2 Clean-up to eliminate interfering species
Interfering species such as aryl sulfuric acids, carboxylic acids, esters, polymeric surfactants,
heterocyclic compounds are eliminated by a cleanup performed by sequential wet column-
chromatography.
6.3 Separation and quantification
(Optional) separation from PCDD/PCDF, (which may be later eluated and analysed), as well as from
other interfering substances on an alumina column.
Final separation and quantitation by gas chromatography (GC) using MS detection mode (see 8.18).
The application of a 60 m column (see 8.3) will ensure that most PCB congeners are separated or
recognizable at different retention times.
Exceptionally a 30 m column may be used for screening. The instrument should comprise automatic
flow and pressure control, programmable temperature controls and auto sampling equipment (see 8.2).
MS detector should preferably be operated in SIM-mode.
NOTE SIM is the most suitable mode for quantitation. SCAN is best for qualitative identification of the
signals, but suffers from reduced sensitivity.
Quantitation is achieved by using the ratio of peak areas of analytes (identified as analyte by three or
more specific mass traces as “qualifiers”) versus the corresponding internal standards areas, to cope
with overlapping ranges of chlorination groups and residual interfering peaks.
There are no intentional chemical reactions except for the dissolution step, which incurs protonation
merely to cleave the crystal lattice, as all other steps are merely physical ones.
Chemical reaction leading to decay of analytes are considered to occur with both the internal reference
material and the analytes alike, assuming full compensation of the resultant error. It is therefore
essential to use internal reference materials matching the congeners distribution profile of the sample
to a relatively high degree. Other approaches to assess artefacts in detail (see example in Reference [1])
shall be mentioned in the test report.
7 Reagents
7.1 Safety precautions
In case of spillage, apply 30 VA ultraviolet lamp for irradiation of spillage areas (254 nm wavelength
emitted power maximum).
Staff is required to be qualified for and familiar with handling of hazardous substances in the laboratory.
All material, solvents, reagents, and standards shall be handled with appropriate care. Laboratory
facilities, equipment and personnel shall comply with the latest legal and safety standards on
PCB handling as may be locally applicable.
Upon accidental skin contact with PCB, triply wipe skin area with polyethylene glycol-wetted cloth (to
be disposed of) and see emergency medical services immediately.
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Major droplet spillages may result in shutdown of the entire laboratory facilities. Protect eyes when
applying UV-lamp irradiation after spillages for decomposing contaminants.
7.2 Reagents, solvents and absorbents
Only reagents and solvents of acknowledged and certified analytical grade for pesticide analyses or
comparable grades shall be used.
Solvents shall be used as delivered. New column adsorbents shall be purged by shaking in and decanting
off dichloromethane (or a similarly suitable solvent), followed by drying under suitable cover.
7.2.1 Sulphuric acid, 92 % to 95 % (mass fraction).
7.2.2 Phosphoric acid, p.a., 85 % (mass fraction).
7.2.3 Diatomaceous earth.
7.2.4 Silica gel, 63 mesh to 200 mesh.
7.2.5 Aluminium oxide (alumina) (Basic, Activity: Super 1).
7.2.6 Silver nitrate, p.a., ultrapure.
7.2.7 Cesium hydroxide, hemihydrate.
7.2.8 Sodium sulfate, p.a., granulated.
NOTE Sodium sulfate (anhydrous) is used to eliminate residual aqueous and alcoholic matter in the hexane
phase, as this can have detrimental effects on the GC column materials.
7.2.9 Porous styrene divinylbenzene beads for size exclusion chromatography.
7.2.10 n-Hexane.
7.2.11 Dichloromethane.
7.2.12 Toluene.
7.2.13 n-Nonane.
7.2.14 Ethanol.
7.2.15 Ethyl acetate.
7.2.16 Cyclohexane.
Original reference solutions shall be diluted by a factor 5 or 2 (MBP-MXP), using n-nonane, octane or
similar high-boiling, non-aromatic solvents. Dilution should be carried out filling up vial content to
2 or 5 times its mass by adding the solvent. The error due to slightly different densities of reference
concentrate and pure solvent is <0,5 %, hence negligible.
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7.3 Internal reference materials for PCBs, 13C12-labelled
1)
— PCB cong. ## 3, 15, 28, 52, 118, 153, 180, 194, 208, 209: LGC/Cambridge #CIL-EC-4189
1)
— PCB cong. ## 3, 8, 28, 52, 101, 118, 138, 153, 180, 194, 206, 209: Wellington-CAMPRO # MBP-MXP
1)
— PCB cong. ## 3, 8, 28, 52, 101, 114, 118, 138, 153, 180, 194, 206, 209: LGC/Cambridge #CIL-EC 5411
These internal reference materials or similar are recommended with respect to the requirement
of a “reporting threshold” value of 2 mg/kg for any resolvable PCB peak, covering in principle all
209 congeners.
Optional: To assess low-chlorinated biphenyls (Mono-CB-s, Di-CB-s) in detail, the user may counter-
check these by using a spiking series for the particular homologue groups.
7.4 Cleaning/disposal agents
All glassware shall be purged with a suitable solvent prior to use and then washed intensively with a
high-alkaline detergent or soap with readily soluble anionic and phosphate-containing surfactants in
order to exclude any source of cross contamination. Joint grease shall be excluded from the laboratory.
New glassware shall be purged by shaking in and decanting off dichloromethane (or a similarly suitable
solvent), followed by drying under suitable cover.
Decontamination soap, brushes for all glassware, discharge bins (separate waste streams); polyethylene
glycol pharmaceutical grade as first aid in case of skin contamination.
8 Apparatus
8.1 Glassware, equipped with B (NS) 29 ground joints only as standard and inverse joint geometry.
8.2 Column (for the clean-up procedure), 30 cm long, 14 mm internal diameter, B (NS) 29/32 shells,
250 ml top reservoir as integral part and PTFE stop cock at the bottom of the column.
8.3 Capillary column (for the gas chromatographic determination) of 60 meters length, internal
diameter 0,25 mm coated with 0,25 µm thick film of 5 % phenylmethylsiloxane equivalent to a phenyl
arylene polymer with the following characteristics:
— non-polar with very low bleed characteristics, ideal for GC-MS;
— excellent inertness for active compounds;
— improved signal-to-noise ratio for better sensitivity and mass spectral integrity;
— bonded and cross-linked;
— solvent rinsable to separate most of the 209 PCB congeners.
NOTE “Fast GC” permitted for particular congeners to be sought (i.e. a selection of the spectrum of 209
congeners for special purposes, to be mentioned in the final report).
8.4 Round-bottomed flasks, B (NS) 29, 1 000 ml, 500 ml and 250 ml.
8.5 Flat-bottomed flasks, 100 ml.
8.6 Cylinders, calibrated, 100 ml and 500 ml.
1)  Examples of suitable products 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.
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8.7 Conical flasks, with ground joint B (NS) 29 and suitable glass stoppers, 500 ml.
8.8 Brown glass bottles, B-(NS) — 1 l, equipped with stoppers.
8.9 Magnetic stirrers.
8.10 Rotary evaporator, with automatic vacuum control; foam-and-flash evaporation stopper flask
recommended.
8.11 Ultrasonic bath, ≥ 250 W.
8.12 Top-load balance, wind-shielded; accuracy to the nearest 0,001 g or better.
8.13 Pneumatic dispensers, 20 µl to 200 µl, 100 µl to 1 000 µl, and suitable tips.
8.14 Separation funnels, 500 ml.
8.15 GC-MS system, complying with the following requirements: GC-MS interfaces constructed of all
glass or glass-lined materials are necessary. Glass can be deactivated by silanizing with dichloro dimethyl
silane. Inserting a fused silica column (8.3) directly into the MS source is recommended. Care must be
taken not to expose the end of the column to the electron beam, see Reference [9].
8.16 Reference material, matching 1 ml GC vials.
8.17 Air conditioning, continuously operating to avoid humidity errors with alumina or sulphuric acid
during benchwork.
8.18 Mass spectrometric detector (MSD).
Unless indicated otherwise, this method merely refers to the electron-impact ionizing (EI) quadrupole-
MS, low resolution MS (QPMS; LRMS), used as a detection and quantitation instrument following
separation of analytes on the GC column
Selective Ion Monitoring (SIM) mode of MSD to be used, with 3 qualifier mass traces to securely identify
a peak as a “positive” by their area ratios.
NOTE In addition, ion trap or CI methods can be applied to yield equal or better results.
8.19 Column (optional), 50 cm long, 20 mm internal diameter, B (NS) 29/32 shells, 250 ml top
reservoir and PTFE stop cock at the bottom of the column.
8.20 Column (optional), 30 cm long, 10 mm internal diameter, B (NS) 29/32 shells, 250 ml top
reservoir and PTFE stop cock at the bottom of the column.
8.21 “Ludwig” extractors (optional), 500 ml, with suitable heating and cooler accessories.
9 Procedure
9.1 Preparation of test sample
Weigh to two decimal places 0,7 g to 1,5 g pigment sample into a 500 ml conical flask and add 0,5 g to
1,0 g ethanol to wet the pigment dropwise until it is completely wetted to form a stiff homogeneously
creeping paste (avoid exceeding 1,5 g ethanol).
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13
Add 100 µl C -labelled reference solution in n-nonane (50 ng to 200 ng/congener preferred) into
12
the flask.
Add anhydrous sodium sulfate using approximately the same mass as the sample; Optional: Add 1 g to
2 g of phosphoric acid to buffer further against over-protonation, and/or to confine interference by
aluminium or iron–III species.
Shake laterally and sonicate for 10 min.
Carefully add 80 g of 92 % to 95 % sulphuric acid stepwise under repeated shaking. The temperature of
the mixture shall be kept at <50 °C to avoid chemical reactions on analytes and standards.
Sonicate the mixture until fully dissolved and a homogenous dark solution is obtained in the sulfuric
acid phase. The temperature shall be kept at <50 °C at all times.
NOTE Inadvertent destruction, cleavage or rearrangement of mono- or di-chlorinated analytes can
be minimized by first contacting the weighed sample, without reference materials, with small amounts of
n-hexane + dichloromethane (1 + 1), drying the sample after centrifugation with decantation of supernatant
organic extract, to be kept separately, then proceeding to spike with internal reference materials and to dissolve
the residual pigment sample in conc. sulphuric acid, uniting organic phases after the liquid-liquid extraction
of the sulphuric acid phase prior to clean-up. In this case, it seems equally appropriate to add mass-labelled
reference materials for mono-and DiCB-s, monitoring isomerization of individual reference compounds and loss/
recovery carefully during the GC-MS phase.
9.2 Liquid-liquid extraction
9.2.1 Separation funnel
Extract the sulphuric acid solution twice with 200 ml
...