Analytical Sciences

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

Hiroaki MINAMISAWA,*  Kenji MURASHIMA,* Mayumi MINAMISAWA,** Nobumasa ARAI,* and Tadao OKUTANI***

*Department of Basic Science and High Technology Research Center, College of Industrial Technology, Nihon University, Shin-ei, Narashino, Chiba 275-8576, Japan
**Department of Bio Technology, Tokyo College of Medico-Phamaco Technology, Higashikasai, Edogawa, Tokyo 134-8530, Japan
***Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Kanda-Surugadai, Chiyoda, Tokyo 101-8308, Japan

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 ug dm^-3, and the relative standard deviations (n = 5) were 3.5 - 4.5% at 1.0 ug/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.

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