Sensitive detection of Pyrraline using a ZnCdSe/ZnS quantum dot molecularly imprinted polyethersulfone fluorescent membrane

This study used the phase inversion method to prepare a novel ZnCdSe/ZnS quantum dot molecularly imprinted (ZnCdSe/ZnS@MIPs) polyethersulfone (PES) fluorescent composite (ZnCdSe/ZnS@MIPs@PES) membrane for the rapid detection of pyrraline (PRL). This membrane addressed the challenges presented by quantum dots molecularly imprinted polymers (QDs@MIPs) particles in liquids and required no pre-treatments during the analysis for accurate content determination at a low LOD. When the samples passed through the membrane via an automatic circulating filtration device, the PRL was specifically adsorbed due to the imprinted recognition sites on the ZnCdSe/ZnS@MIPs particles, causing membrane fluorescence quenching. Matrix-interfering components were removed for the porous structure of the membrane. Compared with the ZnCdSe/ZnS@MIPs solution method, the detection limit and accuracy of the ZnCdSe/ZnS@MIPs@PES membrane technique was significantly more successful in enhancing enrichment and purification functionality, reducing the analysis duration from 3 to 4 d to 45 min, while the operational procedure was decreased from 16 steps to two. When applied for PRL analysis in milk with 15% PES content and 6 mg ZnCdSe/ZnS@MIPs addition, the PRL was quantitatively detected in a broad concentration range (30–1000 μg/L) with R2=0.99. The LOD of ZnCdSe/ZnS@MIPs@PES membrane decreased at a higher sample injection volume, reaching a minimum of 18.1476 μg/L at 14 mL injection.