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 x 105 L mol(-1) cm(-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 0-1.024 mu g/mL with the detection limit (3 sigma) of 7.03 x 10(-4) mu g/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. (c) 2007 Li Yuan. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.