3-[苯并噻唑偶氮]-5-溴-2,6-二羟基苯甲酸与铜的显色反应及其应用

Color reaction and its analytical application of 3-(ben zothiazofeazo)-5-bromo-2,6-bihydroxy benzoic acid with copper

合成了新显色剂3-[苯并噻唑偶氮]-5-溴-2,6-二羟基苯甲酸,用其与Cu2+显色反应,在0.1%溴代十六烷基吡啶(CPB)水溶液存在下,Cu2+与显色剂在pH=6.98的缓冲溶液中形成稳定的1∶2的红色配合物.其最大的吸收波长为533.0nm,表观摩尔吸光系数为3.64×104L·mol-1·cm-1,灵敏度较高,选择性较好.Cu2+含量在0.0014～1.2μg/mL服从比耳定律.此显色反应应用于铝合金和铜锰铸铁中微量Cu2+的测定,结果令人满意.

In order to raise their sensitivity and increasing their solubility, about 40 thiazolylazo dye have been synthesized and used for many purposes, e.g., as the indicator for the titration of metal ions with EDTA and as chelating agent of metal ions. The article introduces the color reaction of the new formed developer with the copper(Ⅱ) under the existence of CPB, it was found that in a buffer solution of pH=(6.98.) (Cu^(2+)) reacts with the developer to form a stable red coordinated complex. Its max-absorption-wavelength is (533.0 nm,) apparent molar absorption coefficient is (3.64 ×(10~4)) (L·mol^(-1)·cm^(-1).) Beer's law is obeyed in the range of (0.001 4~)(1.2 μg/mL) for Cu(Ⅱ). The new reaction system remains to have a high sensitivity and a good selectivity. The method proves to be satisfactory for the direct determination of copper in practical samples.