Determination of Alkyl Benzene Sulfonate in Water

Abstract

This article discusses the development of a procedure for the determination of alkyl benzene sulfonates (ABS), which is based on methylene blue but is perhaps more dependable than the Standard Method. The study found that a mixture of strong chromic acid and sulfuric acid would not measurably attack ABS if the operating temperature was kept below about 45°C and the time of treatment was not extended beyond about 30 min. It appeared reasonable that other organic materials would be oxidized by the chrome sulfuric acid, perhaps after hydrolysis of organic sulfates, phosphates, and the like in the strongly acid medium, and that volatile interfering inorganic anions such as chloride and nitrate could be eliminated by boiling. Other investigations indicated that chloride also might be vaporized in the process as chromyl chloride. Excess chromic acid was reduced to trivalent chromium salt and the resultant mixture subjected to the methylene blue method.