This standard specifies a method for the estimation of the average relative molecular weight of the anionic active material present in the sulfation products of ethoxylated alcohols or alkylphenols, neutralized and currently marketed, which do not contain more than 20 ethylene oxide groups per molecule. These products are also called alkyloxyethylene sulfates (ethoxylated alkylphenol sulfates) and alkylphenoloxyethylene sulfates (ethoxylated alkylphenol sulfates). A general outline of the analysis is presented in Annex A.