ISO 6729:2024

International
Standard
ISO 6729
First edition
Petroleum products and other
2024-09
liquids — Standard test method for
ethanol determination in gasoline
blends by gas chromatography
Produits pétroliers et autres liquides - Éthanol — Détermination
de l'éthanol dans les mélanges d'essence par chromatographie en
phase gazeuse
Reference number
© ISO 2024
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Published in Switzerland
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Reagents . 2
7 Procedure . 2
7.1 Preparation of the apparatus .2
7.2 Preparation of the analytical curve .3
7.3 Sample analysis . .3
8 Expression of results . 3
9 Precision . 4
9.1 General .4
9.2 Repeatability (r) .4
9.3 Reproducibility (R) .4
9.4 Reporting limits.4
Annex A (informative) Example of preparation . 5
Annex B (informative) Reference chromatograms . 6
Bibliography . 9

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Foreword
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This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels and
lubricants from natural or synthetic sources, Subcommittee SC 7, Liquid Biofuels.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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International Standard ISO 6729:2024(en)
Petroleum products and other liquids — Standard test
method for ethanol determination in gasoline blends by gas
chromatography
1 Scope
This document establishes a method for determining the ethanol content in gasoline blends by gas
chromatography (GC). This method is applicable to gasoline samples with ethanol contents ranging from
1,02 % to 52,3 %, in volume fraction.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
gasoline
hydrocarbon fuel or blends thereof, which is liquid at atmospheric pressure and is used in spark ignition engines
4 Principle
A sample is analysed by gas chromatography, using a flame ionization detector, split/splitless injector, nonpolar
column, and external standardization technique for quantifying the ethanol content in gasoline blends.
5 Apparatus
5.1 Gas chromatograph equipped with a flame ionization detector, split/splitless inlet, automatic
sampler, and oven with programmable temperature.
5.2 Electronic instrument for data acquisition, integrated with software for data processing.
5.3 Fused-silica capillary column with nonpolar stationary phase, 100 % dimethylpolysiloxane, and
dimensions of 50 m x 0,20 mm x 0,50 µm.
5.4 Analytical balance, with minimum resolution of 0,1 mg.
5.5 GC autosampler vials (e.g 2 ml of volume capacity) with cap and septa [e.g septa of rubber-membrane/
self-sealing polytetrafluoroethylene (PTFE)].

ISO 6729:2
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