Capillary flow-driven, ZIF-8-enhanced paper-based SERS for ultrasensitive and on-site quantification of acetamiprid residues

The residue of acetamiprid (AAP) in agricultural products poses a threat to food safety. Traditional Surface-enhanced Raman scattering (SERS) detection faces issues such as complex and expensive substrate preparation, and the difficulty of effectively utilizing SERS hotspots due to random molecular diffusion at low concentrations, resulting in low detection sensitivity. Here, we introduced the highly adsorptive 2-Methylimidazole zinc salt (ZIF-8) and developed a portable, ultra-sensitive silver nanoparticle filter paper (FP) loaded with 2-Methylimidazole zinc salt (Ag@FP@ZIF-8) substrate. It was found that the enhancement factor (EF) value for Rhodamine 6G (R6G) when measured using a handheld Raman spectrometer was 1.401 × 10 13 . More importantly, after being kept in a sealed and dark environment at room temperature for 45 days, the signal retention rate remained at 92%. Additionally, it exhibits good uniformity, as evidenced by a relative standard deviation of less than 8.5%. Combining a handheld Raman spectrometer with the previously proposed capillary-assisted sampling method has enabled AAP to be extracted from apple, pear and Bok choy leaves in a shoNeed file 22165rt period of time. The detection limit for Bok choy is 0.01 mg/kg, meeting the requirements of the EU Commission's regulation (EU) 2025/158. This method is expected to be developed into a rapid, deployable solution for on-site pesticide screening.