Competitive adsorption of thiabendazole and pymetrozine on silver surface and simultaneous detection of mixed pesticide residues by surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) for simultaneous detection of multiple pesticides in food samples remains a challenge due to the competitive absorption of multiple analytes on SERS substrate. Herein, a combined method of DFT calculation and SERS experiment was utilized to explore the competitive adsorption of thiabendazole and pymetrozine on silver surface. Subsequently, a SERS method was developed for simultaneous detection of thiabendazole and pymetrozine residues in apples. The simulated parameters of pesticide molecules adsorbed on silver cluster showed that competitive adsorption occurred between thiabendazole and pymetrozine on silver surface, which was further validated by the SERS intensities of single and mixed pesticide solutions. The SERS method was successfully established, featuring a satisfactory linearity range of 1.0–30 and 0.5–15 mg/L with the LOD of 0.9 and 0.4 mg/L for thiabendazole and pymetrozine in apple sample, respectively, and the average recovery was 80.02–120.73 %. The findings not only provide a valuable reference for the investigation of competitive adsorption but also offer a reliable method for the simultaneous detection of multiple pesticide residues in food samples.