PHOTOMETRIC DETERMINATION OF MICRO-AMOUNTS OF ZINC WITH o-HYDROXYBENZENEDIAZOAMINOAZOBENZENE (HBDAAB) AS COLOR REAGENT

In a borate buffer of pH 10.3,and in the presence of OP,a dark reddish colored coordination complex was formed between Zn(Ⅱ) and the color reagent HBDAAB in the mole ratio of (Zn∶R) 1∶2.Absorption maxima of the complex was found at the wavelength of 530 nm,where the molar absorptivity was found to be 1.65×105L·mol-1·cm-1.Beer′s law was kept in the concentration range of 0-40 μg of Zn(Ⅱ) per 25 mL of solution.The proposed method has been applied to the analysis of several kinds of samples (eg.aluminum alloy,grain,human hair,water and etc.) for their zinc contents,giving RSD′s less than 3.2% and recoveries in the range of 97.5%-105.0%.