Size-control synthesis of graphene quantum dots in SBA-15 micro-reactor and fabrication of imprinted polymer-based fluorescence sensor for bisphenol A recognition

This study develops a fluorescent analytical strategy for the determination of bisphenol A (BPA). The fluorescence sensor utilizes SBA-15 as a micro-reactor to fabricate size-controlled graphene quantum dots (GQDs), followed by the synthesis of a GQD-supported polymer (BPA-MIP) via precipitation polymerization using BPA as the template. The fluorescence method demonstrated a direct correlation in the concentration range of 0.5 to 20.00 μmol L⁻¹ for BPA, with a limit of detection (LOD) of 0.180 μmol L⁻¹ and a limit of quantification (LOQ) of 0.564 μmol L⁻¹. Fluorescence decay analysis revealed a lifetime (τ) of 31.87 ns for GQDs and 31.64 ns for BPA-MIP (0.8 μmol L⁻¹ BPA), with the reduced lifetime indicating dynamic quenching behavior, thereby confirming the sensor's capability for BPA detection. The method demonstrated excellent repeatability, with intra- and inter-day relative standard deviations of 1.18 % and 2.01 %, respectively, confirming the reliability of the developed fluorescence sensor. The analysis of selectivity revealed that the proposed fluorescence sensor is highly effective for BPA determination. The proposed fluorescence sensor probe was effectively utilized to three spiked beverage samples, resulting in satisfied recoveries between 100.40 % and 104.80 %.