Synthesis of 1-(4-nitrophenyl)-3-(5-chloropyridyl)-triazene and its color reaction with cadmium

This paper reported the synthesis of a new regent 1-(4-nitrophenyl)-3-(5-chloropyridyl)-triazene(NPCPDT) and the color reaction of NPCPDT with cadmium.In the presence of the surfactant Triton X-100 and in the medium of Na_2B_4O_7-NaOH pH 11.5,the reagent forms a yellow complex with cadmium in the molar ratio of 1∶3.The apparent molar absorptivity is 2.68×10~5 L·mol~(-1)·cm~(-1) by double wavelength spectrophotometry.The measuring wavelength is 440 nm and the reference wavelength is 535 nm.Beer′s law is obeyed in the range of 0～12 μg/25 mL.The method has been applied to the direct determination of cadmium in practical samples and waster water with satisfactory results.