2-[2-(5-甲基苯并噻唑)偶氮]-5-二乙氨基苯甲酸与铜的显色反应研究

Color Reaction of Copper(II) with2- [2- (5-Methylbenzothiazolyl)azo]-5-diethylaminobenzoic Acid

研究了显色剂2－[2-(5－甲基苯并噻唑）偶氮]－5－二乙氨基苯甲酸（5－Me-BTAEB）与Cu^2+的显色反应，试剂与Cu^2+在PH为3．0－5．5的醇－水溶液中形成蓝色稳定的1：1配合物，其最大吸收波长为650nm，表观摩尔吸光系数为7．33×10^4L.mol^-1.cm^-1。Cu^2+的浓度在50－800μg/l时服从比尔定律。

Abstract: We have developed a sensitive spectrophotometric method for measuring microamount of copper with the chromogenic reagent 2-[2-(5-methylbenzothiazolyl) azo]-5-diethylamino benzoic acid (5-Me-BTAEB) developed by us. 5-Me-BTAEB reacts with copper( II ) in aqueous ethanol solution at pH=3. 0~ 5. 5 to form a stable, blue 1 : 1 complex with an absorption maximum at 650 nm. The apparent molar absorptivity is 7. 33×10~4 L.mol-1 .cm-1. Beer's law is obeyed for copper( I ) in the range of 50~800 ug/L. We compare the sensitivity of our reagent with those of other typical heterocyclic reagents in Table 3 for measuring microamount of copper. We have applied our method to measuring microamount of copper in aluminum alloy under certain specified condition with satisfactory results.