Determination of Indium by Graphite Furnace Atomic Absorption Spectrometry after Coprecipitation with Chitosan

A sensitive and simple method for the determination of trace amounts of indium in water samples by graphite furnace atomic absorption spectrometry (GFAAS) after coprecipitation with chitosan was investigated. Indium was quantitatively preconcentrated from water samples by coprecipitation with chitosan at pH 7.0 - 9.0. The coprecipitant was easily dissolved with acetic acid, and indium in the resulting solution was determined by GFAAS. The addition of lanthanum as a chemical modifier was more effective for the atomic absorbance of indium. The detection limit (S/N ≥ 3) for indium was 0.04 μg dm-3, and the relative standard deviations (n = 5) were 3.5 - 4.5% at 1.0 μg/100 cm3. The results obtained in this study indicate that the proposed method can be successfully applied to the determination of trace indium in water samples.