Multifunctional surface-enhanced Raman scattering imaging for detection and visualization of pesticide residues in crops.

Investigating pesticide residues holds paramount significance for ensuring food safety and promoting sustainable agricultural practices. Nevertheless, high-sensitivity analytical techniques are urgent needed due to intricate pesticide combinations, low concentration levels, and complexities in sample preparation. Here, silver nanoparticles synthesized by sodium borohydride reduction created a sprayable multifunctional uniformly dispersed surface-enhanced Raman scattering (SERS) substrate that demonstrated exceptional sensitivity, enabling high-quality signal acquisition of various pesticide residues on different backgrounds for the first-time using SERS imaging strategy. The substrate exhibited an enhancement factor of 108 and a detection limit lower than 10-10 M (0.1 ppb) for pesticides dispersed in colloids. Moreover, the study showcased distinctive detection and quantitative analysis of mixed pesticides, exhibiting excellent linearity (r2 = 0.9983). In addition, SERS imaging technology combined with vertex component analysis and Euclidean distance methods can directly observe the distribution of pesticides outside and inside crops. Overall, this study highlights the potential of SERS and its intuitive imaging approach in pesticide residue detection and distribution visualization, expanding its application in the field of green chemistry.