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在CPC等表面活性剂存在下,铜(Ⅱ)与新显色剂2-(5-溴-2-噻唑偶氮)-5-二乙氨基苯酚(5-Br-TADAP)在pH5—7时形成紫色电中性的胶束增溶络合物。络合物中Cu(Ⅱ)与5-Br TADAP的组成比为1:1,其表观稳定常数为2.7×10~5(20℃,μ=0.1)。该络合物的λmax为580nm,ε580为4.02×10~4L·mol~(-1)·cm~(-1)。与光度测定铜的一些同类噻唑偶氮试剂相比,其灵敏度较高。加入氟化铵等可以消除Fe~(3+)、Al~(3+)等离子的干扰,从而提高了本法的选择性。在25毫升体积中,铜量在0—40微克范围内遵从比耳定律。将本法用于低铜矿和水系沉积物中小量或痕量铜的测定,取得了令人满意的结果。
In the presence of CPC and other surfactants, copper (Ⅱ) and the new color reagent 2- (5-Bromo-2-thiazolylazo) -5-diethylaminophenol A purple, neutral, micellar solubilization complex is formed. The complex ratio of Cu (Ⅱ) to 5-Br TADAP was 1: 1, and its apparent stability constant was 2.7 × 10-5 (20 ℃, μ = 0.1). The λ max of the complex was 580 nm and the ε 580 was 4.02 × 10 -4 L · mol -1 cm -1. Its sensitivity is higher than some of the same thiazolylazo agents for photometric determination of copper. The addition of ammonium fluoride can eliminate the interference of Fe ~ (3 +) and Al ~ (3 +) ions and improve the selectivity of this method. Beer’s law is obeyed in the range of 0-40 micrograms of copper in a 25 ml volume. The method has been applied to the determination of small or trace amounts of copper in low copper and aqueous sediments and has yielded satisfactory results.