Chromogenic Reaction of Mercury With 2-Hydroxy-3-carboxy-5-sulfobenzenediazoaminoazobenzene and Its Application
Guo Zhongxian (Department of Chemical Engineering, Sichuan Institute of Light Industry and Chemical Technology, Zigong 643033)
A highly sensitive color reaction of mercury(Ⅱ) with 2-hydroxy-3-carboxy-5-sul fobenzenediazoaminoazobenzene(HCSDAA) in the presence of p-octylpolyethyleneglycol phenylether(OP) was studied. In borax buffer medium at pH 10.0~10. 5， the redcomplex formed has a maximum absorption at 522 nm， and its apparent molar absorptivity is 1.63× 105 L· mol-1· cm-1, and Sanded sensitivity is 1. 23×10-3μg／cm2. The molar ratio of mer ury(Ⅱ) to HCSDAA In the complex is found to be 1: 2. Beer's law is obeyed in the con centraction range of 0~0． 55mg/L for mercury. The proposed method has been applied to the spectrophotometric direct determination of trace mercury in human hair and waste water with satisfactory results.