This part of ISO 6326 gives a brief description of standardized methods that can be used for the determination of sulfur compounds in natural gas. The principle of each method is described generally, the range of concentrations for which the method is suitable is indicated, and the analytical range and precision of each method is given. It should enable the user to select judiciously the proper method for the application being considered. Sulfur analysis is performed in order to determine a) total sulfur, b) sulfur contained in specific groups (e.g. thiol sulfur), c) individual sulfur compounds, and d) specific groups of sulfur compounds. The standardized methods available in the field of sulfur analysis are ? the Wickbold combustion method: for total sulfur determination (ISO 4260), ? the Lingener combustion method: for total sulfur determination (ISO 6326-5), ? gas chromatography: for determination of individual sulfur compounds (ISO 19739), and ? potentiometry: for determination of hydrogen sulfide, carbonyl sulfide and thiol compounds (ISO 6326-3). Other methods for the determination of sulfur compounds are available but are not considered here. Table 1 gives an overview of the standardized methods which can be used for the determination of total sulfur, hydrogen sulfide, carbonyl sulfide, tetrahydrothiophene, thiol sulfur, individual thiols, individual thiophenes, individual organic sulfides and disulfides.