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合成了新显色剂1 (6 羟基 2 嘌呤基) 3 [4 (苯基偶氮)苯基] 三氮烯(简称HPAPT),研究了它的性质及其与镉显色反应的条件。实验表明,试剂的分子式为C17H13N9,相对分子质量为359,熔点127～129℃,各级酸离解常数为pKa1=4.1,pKa2=7.2,pKa3=10 7。在pH9.0～11.0的Na2B4O7 NaOH缓冲介质中,试剂与镉形成2∶1的红色络合物,表观摩尔吸光系数为2 25×105L·mol-1·cm-1,镉质量浓度在0～0.6mg/L范围内符合比耳定律,在联合掩蔽剂的作用下,可不经分离直接测定环境水样和工业废水中微量镉。
A new reagent, 1 (6hydroxy 2 - purinyl) 3 [4 (phenylazo) phenyl] triazene (HPAPT) was synthesized and its properties and conditions of chromogenic reaction with cadmium were studied. The experimental results show that the formula of the reagent is C17H13N9, the relative molecular mass is 359, the melting point is 127 ~ 129 ℃, and the acid dissociation constants at all levels are pKa1 = 4.1, pKa2 = 7.2 and pKa3 = 107. In the Na2B4O7 NaOH buffer solution with pH 9.0-11.0, the reagent formed a 2: 1 red complex with cadmium, the apparent molar absorptivity was 2 25 × 105 L · mol-1 · cm-1, the mass concentration of cadmium was 0 ~ 0.6mg / L in line with Beer’s law, in the joint masking agent can be directly measured without separation of environmental water samples and industrial wastewater cadmium.