An optosensor based on a hybrid sensing probe of mesoporous carbon and quantum dots embedded in imprinted polymer for ultrasensitive detection of thiamphenicol in milk.

A hybrid fluorescent sensing probe was developed and used to quantitatively analyse thiamphenicol. The probe was constructed by entrapping mesoporous carbon and CdTe*CdS*ZnS quantum dots in molecularly imprinted polymer. The probe was characterized, and the construction and detection conditions were optimized. In the optimized conditions, the recognition sites of the nanoprobe were ultrasensitive and highly selective toward thiamphenicol. The quantitative analysis of thiamphenicol was based on the fluorescence quenching of the hybrid nanoprobe by thiamphenicol. Fluorescence emission was quenched linearly from 0.10 to 100 μg L-1 with a coefficient of determination (R2) of 0.9979. The limit of detection was 0.04 μg L-1. The accuracy of an optosensor based on the hybrid probe was evaluated by analyzing spiked milk samples. The results obtained were compared with the results of high-performance liquid chromatography (HPLC) analysis. The quantitative analysis of the spiked samples with the optosensor agreed well with HPLC analysis. Recoveries were in the range of 93.5 to 100.1 % with good precision (RSD < 5%). The accuracy, speed and convenience of the developed optosensor make it a powerful tool for the detection of thiamphenicol in milk.