Synthesis of 1-(4-nitrophenyl)-3-(4-hydroxy-6-methylpyrimi-dine)-triazene and its color reaction with copper

This paper reports the synthesis of a new reagent 1-(4-p-nitrophenyl)-3-(4-hydroxyl-6-methyl-pyrimidine)-triazene(NPHMPDT) and the color reaction of NPHMPDT with copper.In the presence of the surface-active agent OP and in a Na2B4O7-NaOH buffer medium of pH 11.0,the reagent formed a complex with copper at a molar ratio of 1∶4.The molar absorptivity was 2.81×105 L·mol-1·cm-1 by dual-wavelength determination using a reference wavelength of 460 nm and determination wavelength of 540 nm.The Beer's law was obeyed in the range of 0～480 μg/L.The method has been applied to the direct determination of copper in human hair with satisfactory results.