Solvent-tuned perovskite heterostructures enable visual linoleic acid assay and edible oil species discrimination via wavelength shift.

Linoleic acid (LA) detection and edible oils discrimination are essential for food safety. Recently, CsPbBr 3 @SiO 2 heterostructures have been widely applied in edible oil assays, while deep insights into solvent effects on their structure and performance are often overlooked. Based on the suitable polarity and viscosity of cyclohexane, we prepared CsPbBr 3 @SiO 2 Janus nanoparticles (JNPs) with high stability in edible oil and fast halogen-exchange (FHE) efficiency with oleylammonium iodide (OLAI). LA is selectively oxidized by lipoxidase to yield hydroxylated derivative (oxLA) capable of reacting with OLAI, thereby bridging LA content to naked-eye fluorescence color changes through the anti-FHE reaction. The established method for LA in edible oils exhibited consistent results with GC–MS analysis (p > 0.05). Since the LA content difference between edible oils, we further utilized chemometrics to accurately distinguish (100%) the species of edible oils. Overall, such elaborated CsPbBr 3 @SiO 2 JNPs enable a refreshing strategy for edible oil discrimination. CsPbBr 3 @SiO 2 Janus nanoparticles (JNPs) with high oil stability and fast halide exchange (FHE) activity are finely prepared under solvent regulation. Through catalysis and redox reactions, linoleic acid (LA) is expressed as stable iodine molecules, exhibiting anti-FHE characteristics against JNPs. Accordingly, LA assay and edible oil species discrimination have been realized visually, showcasing the potential of perovskite in food analysis. [Display omitted] • Uniform CsPbBr 3 @SiO 2 Janus nanoparticles (JNPs) are tuned and prepared in cyclohexane. • JNPs exhibit high stability and fast halogen exchange (FHE) activity in edible oil. • Enzymatic anti-FHE enable linoleic acid assay and edible oil species discrimination. [ABSTRACT FROM AUTHOR]