Thioglycolic acid-capped CuInS2/ZnS quantum dots as fluorescent probe for cobalt ion detection

A novel sensing fluorescent probe based on the fluorescence quenching of the thioglycolic acid-capped CuInS 2 /ZnS quantum dots (CuInS 2 /ZnS/TGA QDs) was established for cobalt ions detection. The fluorescence quenching of CuInS 2 /ZnS/TGA QDs was due to the increasing surface deficiency and the inner-filter effect, which were attributed to the reaction between Co 2+ and sulfur bonds on the surface of QDs. The quenching curve could be fitted by a typical Stern–Volmer-type equation, with a linear relationship between the quenching efficiency and the concentration of cobalt ions in the range of 0.3012–90.36   μmol   L −1 . And the detection limit (S/N=3) for Co 2+ was 0.16   μmol   L −1 . Therefore, the established probe provided a simple, rapid, cheap and sensitive method for Co 2+ detection. In a word, this method can be used to detect Co 2+ in the environment.