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International
Standard
ISO 20122
First edition
Vegetable oils — Determination of
2024-04
mineral oil saturated hydrocarbons
(MOSH) and mineral oil aromatic
hydrocarbons (MOAH) with
online-coupled high performance
liquid chromatography-gas
chromatography-flame ionization
detection (HPLC-GC-FID) analysis
— Method for low limit of
quantification
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 3
6 Apparatus . 6
7 Sample . 7
7.1 Sampling .7
7.2 Preparation of the final sample for liquid and solid fats .7
8 Procedures . 8
8.1 General .8
8.2 Hexane/ethanol distribution for removal of interfering substances .8
8.3 Saponification . .8
8.4 Removal of biogenic n-alkanes with aluminium oxide for determination of the MOSH
fraction .9
8.5 Clean-up before epoxidation to separate polar substances .9
8.6 Ethanolic epoxidation of the MOAH fraction to oxidize unsaturated non-aromatic
compounds .9
8.7 HPLC-GC separation .10
8.7.1 HPLC conditions .10
8.7.2 GC configuration .10
8.7.3 Solvent vapour exit configuration .11
8.7.4 Peak identification .11
8.7.5 System suitability test . 12
8.8 Blank run . 13
8.9 Quality control . 13
9 Result of the determination .13
9.1 Testing the chromatograms for sufficient epoxidation and other relevant parameters. 13
9.2 Calculation .14
10 Precision of the method .15
10.1 Repeatability limit . 15
10.2 Reproducibility limit . 15
11 Test report .15
Annex A (informative) Graphics and chromatograms. 17
Annex B (informative) Precision data .28
Annex C (informative) Alternative method for the epoxidation of the MOAH fraction (performic
acid epoxidation) . 41
Bibliography .42
iii
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
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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 document 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).
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This document was prepared by Technical Committee ISO/TC 34 Food products, Subcommittee SC 11,
Animal and vegetable fats and oils, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 307, Oilseeds, vegetable and animal fats and oils and their by-products —
Methods of sampling and analysis, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
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.
iv
Introduction
In order to achieve a low limit of quantification (LOQ), the method contains additional and partially modified
processing steps, specifications for the uniform processing of defined product groups and additional
requirements for system suitability compared to EN 16995:2017.
The method has been tested in an interlaboratory study via the analysis of both naturally contaminated and
spiked vegetable oil samples, ranging from 1 mg/kg to 75 mg/kg for MOSH, and from 1 mg/kg to 7 mg/kg
for MOAH.
v
International Standard ISO 20122:2024(en)
Vegetable oils — Determination of mineral oil saturated
hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons
(MOAH) with online-coupled high performance liquid
chromatography-gas chromatography-flame ionization
detection (HPLC-GC-FID) analysis — Method for low limit of
quantification
1 Scope
This document specifies a procedure for the determination of saturated and aromatic hydrocarbons (from
C10 to C50) in vegetable fats and oils using the online-coupled high performance liquid chromatography-gas
[4][5][6]
chromatography-flame ionization detection (HPLC-GC-FID). This document does not apply to other
matrices.
The method is applicable for the analysis of mineral oil saturated hydrocarbons (MOSH) and/or mineral oil
aromatic hydrocarbons (MOAH).
According to the results of the interlaboratory studies, the method has been proven suitable for MOSH mass
concentrations above 3 mg/kg and MOAH mass concentrations above 2 mg/kg.
In case of suspected interferences, the fossil origin of the MOSH and MOAH fraction can be verified by
examination by GC⨯GC-MS.
An alternative method for the epoxidation of the MOAH fraction (performic acid epoxidation) is proposed
in Annex C. This alternative method provides comparable results to the ethanolic epoxidation of the MOAH
fraction described in 8.6. This alternative method for epoxidation has proven to be efficient for samples with
[14]
a high amount of interferences in the MOAH fraction (e.g. tropical oils).
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 661, Animal and vegetable fats and oils — Preparation of test sample
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases f
...