合成了新试剂2-[2’-(4’-甲基-苯并噻唑)偶氮]-5-二甲氨基苯甲酸,并研究了其与钯(Ⅱ)的显色反应.实验表明,在50%乙醇介质中,该试剂与钻(Ⅱ)反应生成1:l络合物,其最大吸收彼长为698nm,表观摩尔吸光系数为5.83×10~4L·mol~(-1)·cm~(-1).钯量在0~1.3μg/ml范围内符合比尔定律.本法可不经预分离而直接测定催化剂中微量钯,平均回收率为100.4%,结果满意. A new reagent 2- [2 ’- (4’-methyl-benzothiazolyl) azo] -5-dimethylaminobenzoic acid was synthesized and its color reaction with palladium (Ⅱ) was studied. In 50% ethanol medium, the reagent reacts with cobalt (Ⅱ) to form a 1: 1 complex with a maximum absorption of 698 nm and an apparent molar absorptivity of 5.83 × 10 -4 L · mol -1 cm ~ (-1) .The Beer’s law is obeyed in the range of 0 ~ 1.3μg / ml.The method can directly measure the trace palladium in the catalyst without pre-separation, the average recovery is 100.4%, the result is satisfactory.