SYNTHESIS OF 1-(4-AZOBENZENE)-3-(6-METHOXY-2-BENZOTHIAZOLYL)-TRIAZENE AND ITS APPLICATION TO THE PHOTOMETRIC DETERMINATION OF MERCURY

A new chromogenic reagent,1-(4-azobenzene)-3-(6-methoxy-2-benzothiazolyl)-triazene (abbreviated as ABMOBTT),was synthesized and its molecular structure proved by elementay analysis and ultra-red spectrometry.It was found that an orange-red colored complex with mole ratio of (R∶Hg) 2 to 1 by the reaction of ABMOBTT with Hg(Ⅱ) in a borate buffer medium of pH around 10 ( pH 9.5-11.0) and in the presence of Triton X-100.The absorption maxima was found at 520 nm,where the apparent molar absorptivity was found to be 1.50×105L·mol-1·cm-1.Beer′s law was kept in concentration range of 0 to 20 μg of Hg(Ⅱ) per 25 mL of solution.By the addition of sodium pyrophosphate as masking agent,no interference from most of commonly co-existing ions was observed.The proposed method has been used in the determination of mercury in industrial waste water,giving RSD′s less than 3.5%.The analytical results obtained by this method checked very well with the results obtained by the conventional dithizone photometric method.