ASTM D7621-16

1.1 This test method covers procedures (A and B) for the determination of the hydrogen sulfide (H₂S) content of fuel oils such as marine residual fuels and blend stocks, with viscosity up to 3000 mm²s^-1 at 50 °C, and marine distillate fuels, as measured in the liquid phase.

1.2 Procedure A has been shown to eliminate interferences such as thiols (mercaptans) and alkyl sulfides. Procedure B can give elevated results if such interferences are present (see Annex A2).

1.3 Valid ranges for the precision are given in Table 2 and Table 3. Measurements can be made outside these ranges however precision has not been determined.

1.4 Samples containing FAME do not affect the measurement of hydrogen sulfide by this test method.

1.5 The values stated in SI units are to be regarded as standard. Non-SI units given in parentheses are for information only.

1.6 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.