1-(4-nitrophenyl)-3-(2-quinolyl) triazene as an extremely sensitive reagent for spectrophotometric determination of mercury

1-(4-Nitrophenyl)-3-(2-quinolyl)triazene has been synthesized, and used as an extremely sensitive reagent for the spectrophotometric determination of mercury by the decrease in the absorbance of the reagent at 490 nm and pH 9.0-10.8 in the presence of cetylpyridinium bromide. Beer's law is obeyed over the range 0-120 ng/ml Hg(II), the apparent molar absorptivity being 1.0 x 10(6) l.mole(-1).cm(-1). The effect of 69 ionic species or compounds has been examined. Trace mercury in waste water has been determined satisfactorily.