Rapid Detection of Carcinogenic Benzo[ a ]pyrene in Edible Oils Using Dual-Stage Liquid–Liquid Extraction-Assisted SERS

The presence of excessive carcinogenic benzo[a]pyrene (BaP) residues in edible oils poses a significant threat to human health, garnering substantial concern within the international marketplace. Herein, we develop a novel strategy that integrates dual-stage liquid–liquid extraction-assisted surface-enhanced Raman spectroscopy (DSLLE-SERS), to achieve the rapid and quantitative detection of BaP in oils. BaP’s pronounced lipophilic characteristics allows it to exist stably in edible oil for a long period of time, so its extraction from edible oils presents a formidable challenge. To solve this problem, based on the SERS technique, we synthesized a silver sol substrate with high enhancement effect for BaP, which enables trace detection without trivial labeling. Meanwhile, we devised a dual-stage liquid–liquid extraction strategy to avoid matrix interference caused by BaP’s lipid-solubility and ensure the efficient and precise isolation of BaP. Eventually, we achieved a detection threshold as low as 0.5 μg/L for BaP in aqueous solutions, correlating with an R2 value of 0.987, which is indicative of a highly reliable assay. Furthermore, to emulate real-world detection conditions, we introduced BaP into edible oil, successfully achieving a detection limit down to 10 μg/L, and the spiked recovery rate ranged from 80.7 to 112.3%, which demonstrated the feasibility of this method. However, the conventional saponification-solid phase extraction pretreatment method requires at least 30 min. In contrast, the method we developed is simple to operate, fast in detection, and low in cost. It requires only a simple dual-stage extraction process, and the entire process (including pretreatment and detection) can be completed within 10 min. So it offers significant value for both practical application and reference in the advancement of rapid detection technologies for BaP in edible oils. In addition, this method can be further applied to the analysis of other fat-soluble molecules in oil matrices, which has a good prospect of application.