A novel spectrophotometric determination of copper（Ⅱ） with bromosulphonazo Ⅲ

A novel chromogenic reaction involving copper（Ⅱ） and bromosulphonazo Ⅲ （Br-SAZⅢ） in hexamethylenetetramine- hydrochloric buffer solution was investigated. The results showed that a blue complex of copper（Ⅱ） and bromosulphonazo Ⅲ was formed with a molar ratio of 1：1. The apparent molar absorptivity was 3.3×10^5Lmol-1cm-1 and the maximum absorption peak was at 616.8 nm. The proposed procedure was used for quantitative estimation of Cu（II） in the concentration range of 0-1.024μg/mL with the detection limit （3σ） of 7.03 × 10^-4 μg/mL （n = 20）. The relative standard deviations （RSDs） were 0.56-4.68%. Under the optimized conditions, total copper in the vegetables and tea was successfully determined. 2007 Li Yuan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.