Color reaction of 1-(4-nitrophenyl)-3-(3,5-dualbromopyridyl)-triazene with mercury

The synthesis of a new reagent 1-(4-nitrophenyl)-3-(3,5-dualbromopyridyl)triazene(NPDBPDT) and its colour reaction with mercury have been discussed in this paper.In the buffer solution of Na2B4O7-NaOH(pH 11.0) and in the presence of Triton X-100,mercury reagent with the chromogenic reacts to form a complex with molar ratio of 1∶2.This compound has a positive peak at 450 nm and a negative peak at 535 nm.The apparent molar absorptivity is 2.93×105 L·mol-1·cm-1 by using double-wavelength spectrophotometry,which the reference wavelength is at 535 nm and the detersnination at 450 nm.Beer′s law is obeyed in the range of 0～12 μg/25 mL for the concentration of mercury.