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-1) 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-1 (R2, 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.