Spectrophotometric determination of sulphide in water by re-extraction and ligand exchange using chloroform solutions of copper quinolin-8-olate

Abstract

A method based on the decoloration produced in organic solutions of coloured complexes when they are shaken with aqueous solutions of anions is proposed for the spectrophotometric determination of sulphide using dilute chloroform solutions of copper quinolin-8-olate. The effects of several variables on the decoloration (pH, shaking time, volume ratio, etc.) were established. The method is very sensitive (the apparent molar absorptivity at 410 nm is 2.35 × 10⁴ l mol^–1 cm^–1) and can be used for determining sulphide in the presence of other sulphur anions. Trace amounts of sulphide in water were determined spectrophotometrically and the results obtained were compared with those obtained using the methylene blue method.