A dual-emissive ratio fluorescence sensor based on CsPbBr₃ NCs for evaluation of acid value in edible oils

Metal halide perovskites are the research hotspot in evaluating oil quality, but single-emission fluorescence mode often induces errors. Herein, dual-emission CsPbBr₃@Yb-MOFs were prepared to improve the visual resolution and detection robustness, and evaluate acid value of oils. The results presented that CsPbBr₃ NCs were locally grown in micropores and mesopores of Yb-MOFs with 517 and 663 nm fluorescence peaks. Given the reduced I₅₁₇ and constant I₆₆₃, an excellent-positive linear relationship (R² = 0.9901) was found between acid value and I₆₆₃/I₅₁₇ of CsPbBr₃@Yb-MOFs in 0.05-7.08 mg KOH/g. The detection limitation was 0.04 mg KOH/g, and the detection time was about 10 min, and the reaction system could be classified naked-eye. Practical performances with 95 %-103 % recovery rates and 1.7 % RSD were verified in various edible oils. Free fatty acids damaged crystal structure and induced the aggregation of CsPbBr₃ NCs. Thus, a rapid, sensitive and reliable CsPbBr₃@Yb-MOFs-based ratio sensor was developed for evaluating acid value.