Croconium colorimetric probe and preparation method and application

The invention relates to a croconium colorimetric probe. The colorimetric probe is 2,5-bis[3-(4-carboxyl phenyl)-2-methyl benzothiazole] croconium. A preparation method of the colorimetric probe comprises the steps of preparation of 3-(4-carboxyl phenyl)-2-methyl benzothiazole-3 bromine salt and preparation and chromatographic purification of the 2,5-bis[3-(4-carboxyl phenyl)-2-methyl benzothiazole] croconium. The croconium colorimetric probe has the advantages that the synthesis process is simple, the control reaction conditions are easy to control, a pure product can be obtained through simple post-treatment, and the dye has excellent optical performance and optical stability. By adding EDTA, a switching Zn identification sensor is invented. By adding other metal ions, the interference of the 2,5-bis[3-(4-carboxyl phenyl)-2-methyl benzothiazole] croconium in the Zn identification process is not affected by other metal ions. 本发明涉及种克酮酸菁比色探针，比色探针为2,5-双[3-(4-羧基苯基)-2-甲基苯并噻唑]克酮酸菁；比色探针制备方法为3-(4-羧基苯基)-2-甲基苯