Plasmonic COF aerogel for SERS detection of aqueous and gaseous nicotine: The utilization of both electromagnetic enhancement and chemical enhancement

The trace detection of both aqueous and gaseous nicotine is significant for health monitoring and environmental analysis. In this study, a novel covalent organic framework (COF)-based composite was designed to enrich and detect nicotine using surface-enhanced Raman scattering. The negatively charged TpPa-SO 3 H exhibited exceptional enrichment capabilities for nicotine, demonstrating an adsorption capacity of 148.0 mg·g −1 . Chemical interactions, including π-π stacking and acid-base interactions, were observed between the COFs and nicotine molecules. Furthermore, chemical enhancement induced by electron transfer between TpPa-SO 3 H and nicotine was corroborated through energy level analysis. By leveraging the bimetallic synergism between core-shell Au and Ag to achieve electromagnetic enhancement, the TpPa-SO 3 H-Au@Ag composite achieved a detection limit of 6.0 × 10 −10 mol·L −1 for aqueous nicotine. The detection of nicotine in e-cigarette oil and Cambridge filter demonstrates its application capability for different kinds of real samples. By the crosslinking with chitosan, the synthesized aerogel was successfully applied for the on-site gaseous nicotine detection in cigarette smoke. Additionally, the plasmonic aerogel enabled the identification of different kinds of cigarettes using artificial intelligence-assisted gaseous fingerprint spectra recognition and classification.