L-au@ZIF-67@S-au NPs hybrid substrate: A high-performance SERS platform for ultra-trace Fenpropathrin residue detection in Citrus peels

This work reveals a novel SERS enhancement mechanism of “satellite” structure. • Stable and uniform L-Au@ZIF-67@S-Au NPs were synthesized by self-assembly method. • L-Au@ZIF-67@S-Au NPs substrates was prepared with an enhancement factor of 3.4 × 10 6 . • Determination of fenpropathrin in citrus peel, and its LOD reached 0.995 μg/L. A new hybrid substrate of core-satellite plasma MOF, namely L-au @ ZIF-67 @ S au NPs, was developed in this study. The substrate aims to improve SERS performance by combining the molecular trapping layer of ZIF-67 with double electromagnetic hot spots distributed on the inner surface and the outer surface. The interface self-assembly strategy was adopted to combine MOF with plasma nanostructures, thus combining excellent molecular adsorption ability with strong local field enhancement effect. The results showed that the substrate had a low detection limit of 1.43 × 10 −10  M for rhodamine 6G, achieved rapid adsorption equilibrium within 10 min, and showed high signal reproducibility (relative standard deviation, RSD = 1.66%, n  = 20). The substrate was applied to the detection of fenpropathrin residues in citrus peels, showing good sensitivity, and the detection limit was 0.995 μg·L −1 , with an enhancement factor of 3.4 × 10 6 and excellent reproducibility. This work builds a multifunctional and environment-friendly SERS platform, which effectively combines advanced nano-material design with practical applications of food safety monitoring Download: Download high-res image (146KB) Download: Download full-size image