Sensitive SERS sensor for convenient and rapid determination of vanillin in foods.

Sensitive food additive detection is vital for food safety. We developed a flexible nitrocellulose membrane-based SERS substrate modified with silver nanoparticles, enabling additive detection through analyte separation/enrichment and SERS signal enhancement. Integrated with the novel probe 4-(methylthio)benzohydrazide (4-MTBH), the sensor selectively captured vanillin (VA) and ethyl vanillin (EVA) via specific aldehyde-hydrazide interactions, enabling highly sensitive detection. The substrate demonstrated exceptional performance with an enhancement factor of 2.62 × 106, RSD of 3.98 %, and stability maintaining SERS activity for over 30 days with nitrogen protection. It achieved a detection limit of 10-7 mol L-1 for both vanillin flavors, meeting practical requirements, and reliably quantified total vanillin flavorants in diverse real food samples. This work establishes a portable, rapid-response SERS platform for ultrasensitive vanillin detection and introduces a new probe system to the SERS methodology, demonstrating significant potential for analyzing diverse analytes in complex matrices.