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本文研究了新显色剂２－（５－溴－２－吡啶偶氮）－５－二甲氨基苯胺与镍（Ⅱ）的反应条件。试验结果发现，在阴离子表面活性剂十二烷基硫酸钠存在下，在ｐＨ５．２～６．５范围内，试剂与镍（Ⅱ）形成稳定的２∶１配合物。其最大吸收波长在５７０ｎｍ处，表观摩尔吸光系数为１．２４×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。镍（Ⅱ）浓度在０～０．４μｇ·ｍＬ￣（－１）之间符合比尔定律。以硫脲和氟化按作掩蔽剂，可消除Ｃｕ￣（２＋）、Ｐｄ￣（２＋）、Ｆｅ￣（３＋）等离子的干扰。所拟方法用于铝合金中微量镍的测定，结果满意。
In this paper, the reaction conditions of 2- (5-bromo-2-pyridylazo) -5-dimethylaminoaniline with nickel (Ⅱ) were studied. The results showed that the reagent formed a stable 2: 1 complex with nickel (Ⅱ) in the presence of anionic surfactant sodium dodecyl sulfate in the range of pH5.2 ~ 6.5. The maximum absorption wavelength at 570nm, the apparent molar absorption coefficient of 1.24 × 10 ~ 5L · mol ~ (-1) · cm ~ (-1). Beer’s law is obeyed when the nickel (Ⅱ) concentration is between 0 and 0.4 μg · mL -1. Using thiourea and fluorination as masking agents can eliminate the interference of Cu ~ (2 +), Pd ~ (2 +), Fe ~ (3+) ions. The proposed method for the determination of trace nickel in aluminum alloy, the results are satisfactory.