Synthesis of 1-(4-nitrophenyl)-3-(5,6-dimethyl-1,2,4-triazol)-triazene and its color reaction with mercury

The synthesis of a new reagent 1-(4-nitrophenyl) -3-(5,6-dimethyl-1,2,4-triazol)-triazene(NPDMTT),structural characterization and its color reaction with mercury are reported.In the presence of the surface active agent Trition X100 and in the Na2B4O7-NaOH medium of pH 11.0,the reagent with mercury forms a yellow complex with a NPKMTT∶Hg molar ratio of 3:1.The negative absorption maximum of the complex lies at 530nm.The apparent molar absorptivity is 1.34×105 L·mol-1·cm-1.Beer's law is obeyed in the range 0-360μg of mercury.The correlation coefficient is 0.999 8. This method has been applied to determine mercury in industrial waste water with RSD≤ 1.2% and recovery of 98.8%-101.5%.