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研究了 2 -[2 -(5 -甲基苯并噻唑 )偶氮 ]-5 -二乙氨基苯甲酸 (5 -Me-BTAEB)与钴 ( )的显色反应。结果表明 ,在十二烷基硫酸钠 (SDS)存在下 ,试剂与 Co( )在 p H4.1～ 7.3HAc-Na Ac的缓冲溶液中形成稳定的蓝紫色配合物 ,该配合物组成为 n(Co( ) )∶ n (5 -Me-BTAEB) =1∶ 2 ,最大吸收波长为 6 45 nm,表观摩尔吸光系数为 1 .30× 1 0 5L· mol- 1·cm- 1,Co( )浓度在 0～ 8μg/ 2 5 m L 范围内服从比尔定律。该方法可直接用于测定含钴分子筛及维生素 B12 中微量钴 ,结果满意。
The color reaction of 2 - [2 - (5 - methylbenzothiazole) azo] -5 - diethylaminobenzoic acid with cobalt (Ⅱ) was studied. The results show that the reagent and Co () in the presence of sodium dodecyl sulfate (SDS) form a stable blue-violet complex in a buffer solution of pH4.1 ~ 7.3HAc-Na Ac, the complex has a composition of n (Co ()): n (5-Me-BTAEB) = 1: 2, the maximum absorption wavelength was 6 45 nm, and the apparent molar absorptivity was 1.30 × 105 L · mol-1 · cm- () Concentration in the range of 0 ~ 8μg / 2 5 m L obeys Beer’s law. The method can be directly applied to the determination of trace cobalt in cobalt-containing molecular sieve and vitamin B12 with satisfactory results.