Facile high-quantum-yield sulfur-quantum-dot-based photoluminescent probe for nifedipine detection

Monitoring of dihydropyridine drugs, such as nifedipine (NIF), has attracted considerable attention owing to the side effects arising from the consumption of such drugs. Herein, a highly sensitive and facile fluorescence-sensing platform based on a high-quantum-yield sulfur quantum dot (SQDs) probe for NIF detection is proposed. Based on the principle of the inner filter effect, the rapid detection of NIF with high sensitivity is successfully realized on the basis of the change in the fluorescence signal due to the quenching effect of NIF on SQDs. The results show a good linear relationship between the NIF concentration and fluorescence intensity within the range of 5-150 μmol/L, with a low detection limit of 1.63 μmol/L (S/N = 3). Moreover, because no surface modification or establishment of any coupling between the receptor and the fluorophore is necessary, this approach provides considerable flexibility and simplicity for the construction of a fluorescence sensor and substantially reduces the detection time. A systematic investigation was conducted to verify the applicability of this method for the analysis of pharmaceutical components in NIF tablets. This study not only promotes the design and development of a fluorescence analysis platform for NIF detection, but also facilitates the fabrication of novel SQD-based fluorescence-sensing systems for the molecular detection of drugs. Proposal for a facile nifedipine assay method based on the inner filter effect of nifedipine to high-quantum-yield sulfur quantum dots, and realizing nifedipine detection in tablets and human urine samples.