Cadmium telluride quantum dots as pH-sensitive probes for tiopronin determination

The pH-sensitive cadmium telluride (CdTe) quantum dots (QDs) were used as proton probes for tiopronin determination. Based on the fluorescence quenching of CdTe QDs caused by tiopronin, a simple, rapid and specific quantitative method was proposed. Under the optimal conditions, the calibration plot of ln(F0/F) with concentration of tiopronin was linear in the range of 0.15–20 μg mL−1(0.92–122.5 μmol L−1) with correlation coefficient of 0.998. The limit of detection (LOD) (3σ/k) was 0.15 μg mL−1(0.92 μmol mL−1). The content of tiopronin in pharmaceutical tablet was determined by the proposed method and the result agreed with that obtained from the oxidation–reduction titration method and the claimed value.