The determination of chloride by atomic-absorption spectrophotometry

Abstract

A method for the determination of trace amounts of chloride ion in aqueous solution is described. The chloride is converted into phenylmercury(II) chloride which is extracted into chloroform and subsequently determined in ethyl acetate solution by means of atomic-absorption spectrophotometry. Alternatively, but less conveniently, the phenylmercury(II) chloride can be extracted into isopropyl acetate and this solution, after concentration, is sprayed into the spectrophotometer. As little as 0·015 p.p.m. of chloride can be detected in a 250-ml sample of water, and 0·1 p.p.m. of chloride can be determined with a relative mean error of 4·6 per cent. Interferences are minimal but bromide, iodide, thiocyanate and cyanide must be absent from the solution. The present method compares favourably with a previously described gas-liquid chromatographic method, and is only slightly less sensitive.