ASTM D1768 - Sodium Alkylbenzene Sulfonate in Synthetic Detergents by Ultraviolet Absorption
1.1 This test method covers commercial synthetic detergents and built detergent formulations that do not contain organic additives such as amides. Optical dyes and materials normally found in formulated detergents do not interfere; however, materials other than sulfonates that possess strong ultraviolet absorptions must be absent. The indicated sample size and aliquoting scheme is based on samples containing 30 to 40% of active ingredient.
Extracted, with permission, from ASTM D1768-89 - Sodium Alkylbenzene Sulfonate in Synthetic Detergents by Ultraviolet Absorption, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be purchased from ASTM International, astm.org