Photometric Determination of Indium with 2-Hydroxy-5-Sulfo-Benzenediazoaminoazobenzene in the Presence of CTMAB

In a borate buffer solution of pH 10.0 and in the presence of CTMAB,a colored complex was formed between indium(Ⅲ) and 2-hydroxy-5-sulfo-benzenediazoaminoazobenzene,with its absorption maxima at 435 nm and apparent molar absorptivity (ε) 1.3×105L·mol-1·cm-1.Beer′s law was held in the range of 0-14 μg per 25 mL of solution.The proposed method has been applied to the determination of indium in samples of lead powder and tin foil,giving values of RSD′s (n=10) less than 2.5% and averange recovery (n=6) of 103.5%.