Micelle-mediated extraction and spectrophotometric determination of ammonia in water samples utilizing indophenol dye formation

Abstract

A rapid, selective and sensitive cloud point extraction process using the mixture of nonionic surfactant, Triton X-114, and cationic surfactant, cetyltrimethylammonium bromide (CTAB), to extract indophenol formed in the Berthelot reaction with ammonia from aqueous solutions was investigated. The method was based on the color reaction of ammonia with phenol under suitable oxidizing conditions in alkaline medium and cloud point extraction of produced indophenol dye. Effects of reaction and extraction parameters were studied and optimum parameters were established. Linearity was obeyed in the range of 2.00-125.00 ng mL-1 of ammonia. The detection limit of the method was 1.00 ng mL-1 of ammonia. The interference effect of some common ions was also tested. The method was applied to the determination of ammonium in natural water samples. ©2008 Sociedade Brasileira de Química.