Capped cadmium telluride quantum dots fluorescence enhancement by Se(IV) and its application to dietary supplements analysis

Abstract

A thioglycolic capped CdTe probe for Se(IV) detection was optimised by nanocrystal size, pH, buffer composition and concentration, and the order of reagent addition. A large increase in fluorescence (>90%) was observed upon sequential addition of Se(IV), buffer, and CdTe probe, caused by surface passivation due to the presence of singly charged Se(IV) in ammoniacal buffer (0.01 mol L–1) at pH 8.4. This result indicated the possibility of inorganic Se speciation. The method presented a detection limit of 60.5 μg L–1 with RSD ≤ 3.5% (n = 8) and was successfully applied to dietary supplements analysis.