Coprecipitation with disulfide for the determination of traces of cobalt in water by electrothermal atomic absorption spectrometry.
Nanogram quantities of cobalt (II) in 200 ml of water were quantitatively collected at pH 4 on a precipitate of disulfide, which is an oxidation product of dithiol (toluene-3,4-dithiol). The precipitate was separated by filtration and dispersed homogeneously in 2 ml of 0.05 mol l(-1) nitric acid with the aid of ultrasonic irradiation. The suspension was directly analyzed for cobalt by electrothermal atomic absorption spectrometry without serious background absorption. This simple preconcentration technique allows the detection of as little as 3 ng l(-1) (50 pmol l(-1)) of cobalt in water samples. The validity of the method was evaluated by using river and seawater certified reference materials.
Hiraide
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Chen
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Kawaguchi
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