5—〔(3、5—二溴—2—吡啶)偶氮〕—2,4—二氨基甲苯(3,5—二溴—PADAT)可与钴(Ⅱ)发生灵敏的显色反应,但该试剂与铜(Ⅱ)的显色反应则未见报导。本文研究了3,5—二溴—PADAT与铜(Ⅱ)的显色反应条件,络合物组成及其萃取性质,提出了用3,5—二溴—PADAT作显色剂在水相中直接测定铜的新方法。实验结果表明,本法具有灵敏度高、操作简便快速、选择性 5 - [(3,5-Dibromo-2-pyridyl) azo] -2,4-diaminotoluene (3,5-dibromo-PADAT) can develop a sensitive color reaction with cobalt (II) The reagent and copper (Ⅱ) color reaction has not been reported. In this paper, the conditions for the color reaction of 3,5-dibromo-PADAT with copper (Ⅱ), the composition of the complex and its extraction properties were studied. It was proposed that 3,5-dibromo-PADAT A new method for direct determination of copper. The experimental results show that this method has the advantages of high sensitivity, easy operation, quickness and selectivity