Construction of ratio fluorescence sensor based on CdTe quantum dots and benzocoumarin-3-carboxylic acid for Hg2+ detection

A new ratio fluorescence sensor based on mercaptamine capped cadmium telluride quantum dots (Mea-CdTe) and benzocoumarin-3-carboxylic acid (BTA) were constructed. The ratio fluorescence sensor (BTA@Mea-CdTe) was synthesized by amidation reaction between the amino groups on the surface of Mea-CdTe quantum dots and the carboxyl groups of BTA. It is found that Hg2+ ions react with the amino groups on the surface of the quantum dots in the BTA@Mea-CdTe sensor to quench the fluorescence, but it has no effect on the fluorescence of grafted BTA. The sensor has good selectivity and high sensitivity for Hg2+ ions detection. The detection linear range is 0.4–1.2 µM, and the detection limit is 0.03 µM. This ratio fluorescence sensor can be used for Hg2+ visual recognition in water sample detection with obvious color change.