Molecularly imprinted polymers coated CdTe quantum dots with controllable particle size for fluorescent determination of p-coumaric acid.

A facile and sensitive fluorescent sensor based on coating molecularly imprinted polymers onto the surface of CdTe quantum dots (CdTe-QDs@MIPs) was successfully fabricated for selective determination of p-coumaric acid (pCA) for the first time by the strategy of charge transfer principle. MIPs layer was synthesized by one-pot sol-gel reaction using 3-(aminopropyl) triethoxysilane (APTES) as functional monomer and tetraethyl orthosilicate (TEOS) as crosslinker. Controllable particle size of CdTe-QDs@MIPs was formed by simply adjusting the polymerization time. Smaller particle size (about 56 nm) at polymerization time of 5 min reduced embedded sites, and then resulted in fast response (within only 4 min), and high sensitivity (limit of detection, LOD low to 6.74 μg L) for pCA. Different parameters during synthesis and determination procedures affecting the fluorescent probe were optimized. The fluorescent intensity of CdTe-QDs@MIPs was remarkably quenched by pCA compared to CdTe-QDs@NIPs with an imprinting factor of 27.0. Finally, the fluorescence quenching analysis showed excellent linear ranges from 20 to 1000 μg L (R, 0.9964) with distinguished selectivity, and batch-to-batch relative standard deviation (RSD) was 3.8%. The proposed method was applied successfully for the determination of pCA in pineapple juice and kiwi juice with satisfactory recoveries from 92.7% to 106.0%, and precisions below 8.1%. The proposed fluorescent sensor exhibited simple and rapid preparation and detection procedures, high sensitivity and excellent selectivity. It is envisioned that the resultant CdTe-QDs@MIPs offered a new way of rapid and sensitive analysis of pCA in real complex samples.