ISO 23923:2020

INTERNATIONAL ISO
STANDARD 23923
First edition
2020-09
Cigarettes — Determination of
selected volatile organic compounds
in the mainstream smoke of cigarettes
with an intense smoking regime —
Method using GC/MS
Cigarettes — Dosage de composés organiques volatils sélectionnés
dans le courant principal de la fumée de cigarette avec un régime de
fumage intense — Méthode par CG-SM
Reference number
ISO 23923:2020(E)
©
ISO 2020

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ISO 23923:2020(E)

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© ISO 2020
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Published in Switzerland
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ISO 23923:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Reagents . 2
7 Preparation . 2
7.1 Preparation of glassware. 2
7.2 Preparation of standards. 3
7.2.1 General. 3
7.2.2 Preparation of internal standard spiking solution . 3
7.2.3 Preparation of working standards for isoprene, acrylonitrile, benzene,
and toluene . 3
7.2.4 Preparation of working standards for 1,3-butadiene . 4
8 Sampling . 5
9 Tobacco product preparation . 5
10 Sample generation — Smoking of cigarettes . 5
10.1 General . 5
10.2 Smoking machine setup . 5
10.3 Smoking . 7
10.3.1 General. 7
10.3.2 Linear smoking . 7
10.3.3 Rotary smoking . 7
11 Sample analysis . 7
11.1 Preparation of sample. 7
11.2 Determination . 8
11.2.1 GC-MS operating conditions . 8
11.2.2 Calibration . 9
11.2.3 Calculation . 9
12 Repeatability and reproducibility . 9
12.1 General . 9
12.2 Results of the 2012 collaborative study .10
13 Test report .12
Annex A (informative) Examples of chromatograms .13
Bibliography .17
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ISO 23923:2020(E)

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 126, Tobacco and tobacco products.
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.
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ISO 23923:2020(E)

Introduction
The CORESTA (www .coresta .org) Special Analytes Sub-Group (since 2017 the Sub-Group changed
its name to Smoke Analytes Sub-Group) carried out a collaborative study in 2005 to compare smoke
analyte yields of selected volatile organic compounds (volatiles) obtained from different laboratories
using their own preferred methodologies. This study reported significant and unacceptable differences
in volatiles yields, especially for 1,3-butadiene and acrylonitrile and suggested that further work was
required to understand factors influencing the variability. Key parameters of existing methodologies
[1] [2]
were reviewed and further studies were conducted on selected volatiles between 2008 and 2009 .
These studies investigated critical method steps that required optimization before incorporation
into a CORESTA Recommended Method (CRM). The CRM was based on collecting the volatiles from
mainstream cigarette smoke in cryogenically cooled impinger traps containing methanol. The impinger
solutions were fortified with benzene-D and analysed by gas chromatography/mass spectrometry
6
(GC-MS).
This document was produced through a CORESTA collaborative study conducted in 2011, involving 17
[3]-[5]
laboratories from 11 countries and included 10 samples with different tar yields . Cigarettes were
smoked with the intense smoking regime specified in Health Canada Official Method T-115 (equivalent
to ISO 20778). Statistical evaluations carried out according to ISO 5725-1 and ISO 5725-2 are included.
No machine smoking regime can represent all human smoking behaviour.
— It is recommended that cigarettes also be tested under conditions of a different intensity of machine
smoking than those specified in this document.
— Machine smoking testing is useful to characterize cigarette emissions for design and regulatory
purposes, but communication of machine measurements to smokers can result in misunderstandings
about differences in exposure and risk across brands.
— Smoke emission data from machine measurements may be used as inputs for product hazard
assessment, but they are not intended to be nor are they valid as measures of human exposure or
risks. Communicating differences between products in machine measurements as differences in
exposure or risk is a misuse of testing using International Standards
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INTERNATIONAL STANDARD ISO 23923:2020(E)
Cigarettes — Determination of selected volatile organic
compounds in the mainstream smoke of cigarettes with an
intense smoking regime — Method using GC/MS
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not purport to address all the safety problems associated with
its use. It is the responsibility of the user of this document to establish appropriate safety and
health practices and determine the applicability of any other restrictions prior to use.
1 Scope
This document specifies a method for the quantification of selected volatile organic compounds (VOCs:
1,3-butadiene, isoprene, acrylonitrile, benzene and toluene) by gas chromatography/mass spectrometry
(GC-MS) in mainstream cigarette smoke using ISO 20778 smoking parameters.
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 3402, Tobacco and tobacco products — Atmosphere for conditioning and testing
ISO 8243, Cigarettes — Sampling
ISO 20778, Cigarettes — Routine analytical cigarette smoking machine — Definitions and standard
conditions with an intense smoking regime
ISO 20779, Cigarettes — Generation and collection of total particulate matter using a routine analytical
smoking machine with an intense smoking regime
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Principle
Selected volatiles are collected by passing the mainstream smoke of cigarettes through a glass fibre
filter pad as specified in ISO 20778 into cryogenic traps containing methanol.
The impinger solutions are fortified with internal standard and analysed by GC-MS.
5 Apparatus
In addition to the list provided below, usual laboratory apparatus and equipment are needed for
preparation of samples and standards.
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ISO 23923:2020(E)

5.1 Impinger trapping system, capable of being connected in series, a cryogenically cooled liquid
impinger to efficiently trap volatiles present in the vapour phase of mainstream smoke.
5.2 GC-MS system, to obtain chromatographic data.
The GC shall be configured to perform split injections on a capillary column and operated in Selected
Ion Monitoring mode (SIM or equivalent).
5.3 Gas tight syringes, of appropriate volumes.
5.4 Fused silica capillary column, for example DB-624, length 60 m with internal diameter of
0,25 mm and 1,4 µm film thickness, or equivalent.
5.5 Spectrophotometer, to estimate 1,3-butadiene concentration in secondary stock solution.
6 Reagents
6.1 Dry ice.
6.2 Isopropanol, for Dewar flasks.
6.3 Methanol, HPLC grade or better.
The methanol should be checked to ensure the background levels of the analytes will not negatively
affect the analysis.
6.4 Ethanol, reagent grade or equivalent.
6.5 Benzene-D , min. 99 atom % D; checked for the absence of not-labelled analogue.
6
6.6 Toluene-D , min. 99 atom % D; checked for the absence of not-labelled analogue.
8
6.7 1,3-Butadiene, min. 99 %.
6.8 Isoprene, min. 99 %.
6.9 Acrylonitrile, min. 99 %.
6.10 Benzene, min. 99 %.
6.11 Toluene, min. 99 %.
7 Preparation
7.1 Preparation of glassware
Glassware shall be cleaned and dried in such a manner which ensures that contamination from
glassware does not occur.
It is important that all possible sources of contamination are removed from the work area.
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ISO 23923:2020(E)

7.2 Preparation of standards
7.2.1 General
Where available, certified reference solutions of the selected volatile organic compounds and internal
standards can be used.
7.2.2 Preparation of internal standard spiking solution
7.2.2.1 Internal standard stock solution
Transfer the contents of a 1 g ampoule of benzene-D into a 10 ml amber volumetric flask. Dilute to
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volume with methanol.
The inclusion of other internal standards, such as toluene-D , may also be suitable. Laboratories shall
8
demonstrate the suitability of the inclusion of additional internal standards.
7.2.2.2 Internal standard spiking solution
Using a volumetric pipette, transfer 4 ml of the stock solution (7.2.2.1) into a 100 ml volumetric flask
and dilute to volume with methanol. This solution has a concentration of 4 000 µg/ml.
7.2.2.3 Storage
Store the diluted solutions in 25 ml vials with PTFE-lined caps in freezer at approximately –20 °C
7.2.3 Preparation of working standards for isoprene, acrylonitrile, benzene, and toluene
7.2.3.1 Primary isoprene, acrylonitrile, benzene and toluene stock solutions
Using gas tight syringes, weigh accurately 100 mg of isoprene, acrylonitrile, benzene, and toluene into
separate 10 ml amber volumetric flasks that are half filled with methanol. Dilute each compound to
volume with methanol. Each solution has a nominal concentration of 10 mg/ml.
NOTE Approximate volumes corresponding to 100 mg are: isoprene = 150 µl, acrylonitrile = 140 μl,
benzene = 130 μl, toluene = 120 µl.
7.2.3.2 Secondary stock solution (mixture of isoprene, acrylonitrile, benzene and toluene
primary stock solutions)
A combined secondary stock solution is prepared by transferring appropriate amounts (Table 1) of
isoprene, acrylonitrile, benzene, and toluene primary stock solutions (7.2.3.1) into a 50 ml volumetric
flask that is a third full with methanol. Dilute to volume with methanol.
Table 1 — Preparation of secondary stock solution
Approximate
Volume of primary stock
Analyte concentration
(ml)
(μg/ml)
Isoprene 3,0 600
Acrylonitrile 1,0 200
Benzene 1,0 200
Toluene 1,0 200
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ISO 23923:2020(E)

7.2.3.3 Calibration standard solutions (for isoprene, acrylonitrile, benzene and toluen
...