Facile synthesis of 2-MCE capped silver shell optimized core-shell nanosensor for simultaneous detection of insecticide residues in fruit samples

Surface-enhanced Raman scattering (SERS) is an emerging swift and nondestructive detecting method, offering a unique structural signature of analytes down to ultrasensitive levels. Herein, we present a novel SERS-based core-shell nanostructure with optimized silver shell thicknesses, capped with 2-mercaptoethylamine (2-MCE), to simultaneously detect multiple agrochemical residues in fruit samples. Compared to unmodified Au@AgNPs, the modified Au@Ag@2-MCENPs integrated with SERS exhibited improved sensitivity and stability, exhibiting a strong relationship between the SERS intensities and pesticide concentrations in the fruit samples, with LODs of 0.006 and 0.008 ppm for thiacloprid and 0.007 and 0.009 ppm for oxamyl in pear and apple fruit samples, respectively. Moreover, the method showed satisfactory recoveries ranging from 80 % to 106.5 % for thiacloprid and 81.8 % to 110.2 % for oxamyl in both fruit samples. Furthermore, this method presented rapid and simultaneous detection capabilities, significantly reducing analysis time compared to traditional methods, making it suitable for detecting other toxic chemical residues in agricultural products.