ISO 3924 Petroleum products - Determination of boiling range distribution - Gas chromatography method
WARNING - The use of this International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1 Scope
This International Standard specifies a method for the determination of the boiling-range distribution of petroleum products. The method is applicable to petroleum products and fractions with a final boiling point of 538 °C or lower at atmospheric pressure as determined by this International Standard. This International Standard is not applicable to gasoline samples or gasoline components. The method is limited to products having a boiling range greater than 55 °C and having a vapour pressure sufficiently low to permit sampling at ambient temperature.

The method has successfully been applied to samples containing biodiesel up to 10 %.

NOTE For the purposes of this International Standard, the term "% (m/m)" is used to represent the mass fraction of a material.

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.
ISO 3170:2004, Petroleum liquids - Manual sampling
ISO 3171:1988, Petroleum liquids - Automatic pipeline sampling
ISO 3405:2000, Petroleum products - Determination of distillation characteristics at atmospheric pressure
ISO 4259:2006, Petroleum products - Determination and application of precision data in relation to methods of test

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 initial boiling point (IBP)
temperature corresponding to the retention time at which a net area count equal to 0.5 % of the total sample area under the chromatogram is obtained.

3.2 final boiling point (FBP)
temperature corresponding to the retention time at which a net area count equal to 99.5 % of the total sample area under the chromatogram is obtained.

3.3 slice rate
number of data slices acquired per unit of time used to integrate the continuous (analogue) chromatographic detector response during an analysis.

NOTE The slice rate is expressed in hertz (for example slices per second).

4 Principle
A sample is introduced into a gas chromatographic column, which separates hydrocarbons in the order of increasing boiling point. The column temperature is raised at a reproducible rate and the area under the chromatogram is recorded throughout the analysis. Boiling temperatures are assigned to the time axis from a calibration curve, obtained under the same conditions by running a known mixture of hydrocarbons covering the boiling range expected in the sample. From these data, the boiling range distribution is obtained.

Annex A presents a correlation model for the calculation of physical distillation (ISO 3405-, IP 123- or ASTM D86-equivalent data) from boiling-range distribution analysis by gas chromatography determined following this International Standard.

Annex B describes an alternative, accelerated analysis.