[Determination of trace amounts of mercury by spectrophotometric method with 2-hydroxy-5-sulfobenzenediazoaminoazobenzene].

The chromogenic reaction of 2-hydroxy-5-sulfobenzenediazoaminoazobenzene (HSDAA) with mercury was studied. In the presence of Triton X-100 and in a borax-buffer solution of pH 10.30, mercury(II) reacted with HSDAA to form a stable orange-red complex with molar radio of 1:2. The apparent molar absorptivity was 1.67 x 10(5) x L mol(-1) x cm(-1) with the maximum absorption wavelength of 519 nm. Beer's law was obeyed in the concentration range of 0-600 microg x L(-1) for Hg(II). The method was applied to the determination of trace amounts of mercury in water with satisfactory results.