Fluorescence enhancement of glutathione capped CdTe/ZnS quantum dots by embedding into cationic starch for sensitive detection of rifampicin.

In this study, we describe the synthesis of a new quantum dots (QDs) by embedding glutathione capped CdTe/ZnS QDs into cationic starch biopolymer (CS-GSH-CdTe/ZnS QDs). The fluorescence intensity of prepared QDs was significantly enhanced. When QDs interacted with rifampicin, the fluorescence intensity of the CS-GSH-CdTe/ZnS QDs was highly quenched compared with GSH-CdTe/ZnS QDs. Based on the above, a new fluorescent nanosensor for simple, sensitive and selective detection of rifampicin was developed. The fluorescence quenching was well described by the typical Stern-Volmer equation. After optimization, the linear range of the as-prepared QDs fluorescence intensity versus the concentration of rifampicin was F0 /F=0.0422Q+1.109 (R2 =0.99). The detection limit was 0.06×10-6 mol/L. The proposed method with satisfactory results was used to detect rifampicin in commercial capsules and tablets.