Synthesis of NPHMPDT and its color reaction with cadmium

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 cadmium. In the presence of the surfactant OP and in the Na2B4O7-NaOH medium of pH 11.0, the reagent form a complex with cadmium in the molar ratio of 1∶3. The apparent molar absorptivity is 4.88×105 L·mol-1·cm-1 by double wavelength spectrophotometry. The measuring wavelength is 450 nm and the reference wavelength is 540 nm. Beer′s law is obeyed in the range of 0～480 μg/L. The method has been applied to the direct determination of cadmium in waster water with satisfactory results.