Synthesis of 1-(4-nitrophenyl)-3-(5-methypyridyl)-Triazene and Its Color Reaction with Copper

The synthesis of 1-(4-nitrophenyl)-3-(3-methypyridyl-triazene(NPMPDT) and the color reaction of NPMPDT with copper was reported. In the presence of the surface active agent OP and in the Na_2B_4O_7_NaOH medium of pH 10.5,the reagent form a yellow complex with copper in the molar ratio of 1∶2. The molar absorptivity is 2.18×10~ 5 L·mol~ -1 ·cm~ -1 by dual_wavelengh of 460 nm and determination wavelengh of 535 nm. Beer's law is obeyed in the range of 0～0.48 μg/mL.The method has been applied to the direct determination of copper in rice and flour samples with satisfactory results.