A knowledge of the hydrocarbon composition of process streams and petroleum products boiling within the range of 205 to 540°C (400 to 1000°F) is useful in following the effect of changes in process variables, diagnosing the source of plant upsets and in evaluating the effect of changes in composition on product performance properties.

This test method, when used together with Test Method D3239, provides a detailed analysis of the hydrocarbon composition of such materials.

1.1 This test method covers the determination by high ionizing voltage mass spectrometry of seven saturated hydrocarbon types and one aromatic type in saturate petroleum fractions having average carbon numbers 16 through 32. The saturate types include alkanes (0-rings), single-ring naphthenes, and five fused naphthene types with 2, 3, 4, 5, and 6 rings. The nonsaturate type is monoaromatic. Noncondensed naphthenes are analyzed as single rings. Samples must be nonolefinic and must contain less than 5 volume % monoaromatic. Composition data are in volume percent.

1.2 The values stated in acceptable SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.

1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.