本文报道了新显色剂3—氯—4(2-硝基—4—甲基苯基重氮氨基)偶氮苯的合成及其与镉的显色反应。在非离子表面活性剂Triton X—100存在下,于pH9.5的Na_2B_4O_7—NaOH缓冲溶液中,试剂与镉生成2:1的红色配合物,其配合物的最大吸收波长位于524nm处,表观摩尔吸光系数ε=1.34×10~5L·mol~(-1)~cm~(-1),镉量在0 12μg/25ml范围内符合比尔定律,方法曾用于标准水样及电镀废水中微量镉的测定,结果满意。 This paper reports the synthesis of a new chromogenic reagent 3-chloro-4 (2-nitro-4-methylphenyldiazoamino) azobenzene and its color reaction with cadmium. In the presence of non-ionic surfactant Triton X-100, a 2: 1 red complex was formed between the reagent and cadmium in Na2B4O7-NaOH buffer solution at pH 9.5. The maximum absorption wavelength of the complex was 524 nm. Beer ’s law, Beer’ s law, Beer ’s law, Beer’ s law, Beer ’s law, Beer’ s law, the extinction coefficient ε = 1.34 × 10-5L · mol -1 -1 cm -1. Determination of cadmium, the results are satisfactory.