3,5-二(4-苯偶氮苯氨基重氮基)苯甲酸的合成及其与镍(Ⅱ)的显色反应

Synthesis of 3,5-bis(4-phenylazophenylaminodiazo) benzoic acid and its colour reaction with nickel

合成了一种新型的双三氮烯类显色剂3，5-二（4-苯偶氮苯氨基重氮基）苯甲酸（BPAAD），并对该试剂与Ni（Ⅱ）的显色反应进行了研究。实验表明，在Triton X-100存在下，pH10．0的硼砂-氢氧化钠缓冲溶液中，该试剂与Ni（Ⅱ）形成了2：1的红色络合物，其最大吸收波长位于500nm处，表观摩尔吸光系数ε为1．46×10^5L·mol^-1·cm^-1，25mL溶液中，镍的浓度在0～0．8μg范围内遵守比尔定律。研究了测定铝合金中镍的各种条件和共存离子的影响，加入混合掩蔽剂后，可提高Al^3＋，Fe^3＋，Cu^3＋，Hg^2＋，Cd^2＋的允许量。方法用于测定铝合金中镍，结果与认定值和原子吸收光谱法测定值相符，相对标准偏差（n=5）为2．5％～3．8％。

A new chromogenic reagent 3,5-bis（4-phenylazophenylaminodiazo） benzoic acid （BPAAD） is synthesized and its color reaction conditions with Ni（Ⅱ） are studied. In the buffer solution of Na2B4O2-NaOH at pH 10.0 and in the presence of TritonX-100, the chromogenic reagent reacts with nickel（Ⅱ） to form a red complex（2 ： 1）. The maximum absorption wavelength of the complex is at 500 nm, and the apparent molar absorptivity is 1.46 × 10^5 L · mol^-1 · cm^-1. Beer＇s law is obeyed in the range of 0-0. 8μg for nickel（Ⅱ） in 25 mL. The conditions for determining nickel and the effects of coexistent ions on the determination are examined. Adding masking reagent, the allowable amounts of Al^3＋, Fe^3＋, Cu^2＋, Hg^2＋, Cd^2＋ are increased. This method has been used for the determination of nickel in aluminum alloy samples with RSD of 2.5%-3.8%（n=5） and the results are agreement with those obtained by atomic absorption spectrometry.