Determination of Doxorubicin by Luminescence Quenching of Alloyed Quantum Dots

A sensitive and a simple method is developed for determining doxorubicin (Dox) in biological fluids without complex sample preparation. The method is based on the luminescence quenching of CdZnSeS/ZnS quantum dots (QDs) stabilized with thioglycolic acid. The luminescence quenching was investigated in model solutions and human blood plasma to determine the optimal determination parameters. The best conditions for detecting doxorubicin included QDs of an optical density Aλ=360 = 0.05 and a 25-fold plasma dilution. The method was applied to the analysis of a human blood sample. The limit of detection for doxorubicin was 0.02 μg/mL, the limit of quantification was 0.18 μg/mL, and the linear range was 0.27–4.07 μg/mL (R2 > 0.96). The method demonstrated good reproducibility (RSD 1.08–1.19%). High-performance liquid chromatography with UV detection confirmed the accuracy of the method.