ASTM D2425 : 21

1.1 This test method covers an analytical scheme using the mass spectrometer to determine the hydrocarbon types present in conventional and synthesized hydrocarbons that have a boiling range of 160 °C to 343 °C (320 °F to 650 °F), 5 % to 95 % by volume  as determined by Test Method D86. Samples with average carbon number value of paraffins between C₁₂ and C₁₆ and containing paraffins from C₁₀ and C₁₈ can be analyzed. Eleven hydrocarbon types are determined. These include: paraffins, noncondensed cycloparaffins, condensed dicycloparaffins, condensed tricycloparaffins, alkylbenzenes, indans or tetralins, or both, C_nH _2n-10 (indenes, etc.), naphthalenes, C_nH_2n-14  (acenaphthenes, etc.), C_nH _2n-16 (acenaphthylenes, etc.), and tricyclic aromatics.

1.2 This test method is intended for use with full boiling range products that contain no significant olefin content.

Biodiesel (FAME components) could interfere with the separation of the sample and the characteristic mass fragments of FAME compounds are not defined in the procedure.

Hydrocarbons containing tertiary carbon fragments, sometimes found in synthetic aviation fuels, will interfere with the characteristic mass fragments of paraffins and result in a false, elevated cycloparaffin content.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For a specific warning statement, see 11.1.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International StandardDetails, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.