ISO 20846

Description / Abstract: This International Standard specifies an ultraviolet (UV) fluorescence test method for the determination of the sulfur content of motor gasolines containing up to 3,7 % (m/m) oxygen [including those blended with ethanol up to about 10 % (V/V)], and of diesel fuels, including those containing up to about 10 % (V/V) fatty acid methylester (FAME), having sulfur contents in the range 3 mg/kg to 500 mg/kg. Other products can be analysed and other sulfur contents can be determined according to this test method, however, no precision data for products other than automotive fuels and for results outside the specified range have been established for this International Standard. Halogens interfere with this detection technique at concentrations above approximately 3 500 mg/kg.

NOTE 1 Some process catalysts used in petroleum and chemical refining can be poisoned when trace amounts of sulfur-bearing materials are contained in the feedstocks.

NOTE 2 This test method can be used to determine sulfur in process feeds and can also be used to control sulfur in effluents.

NOTE 3 For the purposes of this International Standard, the terms "% (m/m)" and "% (V/V)" are used to represent the mass fraction and the volume fraction of a material respectively.

NOTE 4 Sulfate species in ethanol do not have the same conversion factor of organic sulfur in ethanol. Nevertheless, sulfates have a conversion factor close to that of organic sulfur.

NOTE 5 It is preferable to check the nitrogen interference and to take it into account, especially when sulfur content is measured on diesel blended with cetane improver containing nitrogen. For example, alkyl nitrate, as 2-ethyl hexyl nitrate (EHN), added as cetane improver to diesel fuel shows an enhancing effect on sulfur content that can range from 0 to 1,7 mg/kg when 2 000 mg/kg EHN is added to diesel fuel containing 10 mg/kg sulfur.