Spectrophotometric determination of mercury(II) with 5,6-diphenyl-2,3-dihydro-asym-triazine-3-thione

A highly selective spectrophotometric method is described for the determination of 0.05–0.55 mg mercury using 5,6-diphenyl-2,3-dihydro-asym-triazine-3-thione (DDTT). The yellow 1:2 complex is extractable into chloroform at pH 10, having a maximum absorbance at 430 nm, ? = 8.1 × 10³M^?1 cm^?1. The only interfering ions are CN^?, Tl(I), and Pd(II). The method was applied to the determination of mercury in organomercury compounds and to the estimation of the solubility product of mercurous sulfate.