Flash evaporation-driven surface-enhanced Raman scattering for trace molecular detection of food contaminants

This study presents a flash evaporation-driven surface-enhanced Raman scattering (FESERS) substrate for ultrasensitive food contaminant detection. A stable, reusable Ag nanoparticles (Ag NPs) substrate, fabricated via ascorbic acid-citrate dual-reduction coupled with interfacial self-assembly, yielded the actual enhancement factor (AEF) of 7.54 × 10⁵ while exhibiting a low SERS signal relative standard deviation (RSD) of 5.24 %. Signal amplification utilized 80 °C droplet flash evaporation cycles, while the coffee ring effect concentrated analytes at 0.6 mm from the droplet center. The method achieved detection limits of 0.01 nM for three food contaminants. Validation with real samples (mung bean sprouts, chili powder, lake water) showed high reliability, as evidenced by near-identical ratio curves between actual-sample pollutant peaks and aqueous-solution calibration curves using citrate anion as an internal standard. This approach provides a sensitive, reproducible, and convenient for food safety monitoring.