Synthesis of molecularly imprinted polymer on carbon quantum dots as an optical sensor for selective fluorescent determination of promethazine hydrochloride

An optical sensor based on carbon quantum dots (CQDs) coated with molecularly imprinted polymers (MIPs) was fabricated for selective and sensitive determination of promethazine hydrochloride (PrHy). Water-soluble and fluorescent CQDs were synthesized by a simple, low cost and green approach using orange juice as a carbon source. The special advantage of the synthesized CQDs with this method is low toxicity. The surface of the CQDs was covered with MIPs matrix (CQDs-MIPs) via sol-gel polymerization. For characterization of the CQDs and CQDs-MIPs, UV–vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering technique, X-ray diffraction technique, Fourier transform infrared spectroscopy, and transmission electron microscopy were used. The fluorescence intensity of CQDs-MIPs exhibited linear response with the concentration of PrHy in the range from 2.0 to 250 μmol L−1 with a detection limit of 0.5 μmol L−1. The reproducibility of the method was checked for 20 μmol L−1 of PrHy, and the results showed RSD% as 5.1. This sensor was used for determination of PrHy in real samples and showed satisfactory results.