Determination of ppt Level of Cobalt in Water by Graphite Furnace Atomic Absorption Spectrometry after Preconcentration with 2-Nitroso-1-naphthol Chelate Extraction

摘要

A new and simple method for the determination of ppt (ng/l) levels of cobalt in aqueous samples is described. The method involves the extraction of cobalt into m-xylene as its 2-nitroso-1-naphthol Chelate, followed by elimination of the other metals and the excess reagent extracted in the m-xylene by the successive washing with hydrochloric acid and sodium hydroxide solution. Finally the cobalt in the m-xylene is determined by graphite furnace atomic absorption spectrometry. Since the formation and extraction properties of cobalt 2-nitroso-naphthol chelate are specific and selective, the resulting m-xylene contains only the cobalt chelate. More than 2ng of cobalt in 1l of aqueous sample (2ppt) can be accurately determined without the effects of many other substances.