Competition-resistant Au@Ag core-shell SERS substrates combined with a multilayer perceptron for simultaneous identification of mixed pesticides

This study developed a novel SERS detection platform based on seed-mediated synthesis of core-shell structured Au@Ag NPs. Benefiting from the atomic synergistic effects between the gold core and silver shell, the substrate demonstrated exceptional stability, enabling simultaneous dual-target detection of Thiram and Paraquat. Experimental results revealed linear response ranges of 1.0 × 10 −6 –1.0 × 10 −4  M (LOD: 6.89 × 10 −8  M) at 1380 cm −1 for Thiram, and 1.0 × 10 −5 –1.0 × 10 −3  M (LOD: 9.75 × 10 −6  M) at 840 cm −1 for Paraquat. Spiked recovery rates in apple samples reached 95.6%–102% for Thiram and 95%–98.4% for Paraquat. Quantitative analysis of mixed systems using an MLP model achieved 91% accuracy, 89% recall, 89% F1-score, and 90% precision. This method provides a highly sensitive and reliable technical solution for simultaneous detection of multiple pesticide residues in complex food matrices, demonstrating significant potential for rapid food safety monitoring applications.