ISO 20846:2019 specifies an ultraviolet (UV) fluorescence test method for the determination of the sulfur content of the following products:— having sulfur contents in the range 3 mg/kg to 500 mg/kg,— motor gasolines containing up to 3,7 % (m/m) oxygen [including those blended with ethanol up to about 10 % (V/V)],— diesel fuels, including those containing up to about 30 % (V/V) fatty acid methyl ester (FAME),— having sulfur contents in the range of 3 mg/kg to 45 mg/kg,— synthetic fuels, such as hydrotreated vegetable oil (HVO) and gas to liquid (GTL).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 document. 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 document, "% (m/m)" and "% (V/V)" are used to represent the mass fraction, w, and the volume fraction, φ, 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 Nitrogen interference can occur, see 6.5 for further guidance.