LAUSR

The peroxide number of edible oil relates to its quality. The classical determination methods for the peroxide number are still unsat-isfactory due to their complexity and poor reproducibility in the analytical process, and incapability of field rapid detection. In this study, a novel wavelength-shift based visual method has been developed for the peroxide number determination of edible oil using halide perovskite nanocrystals (CsPbBr3 NCs). In the analysis, the edible oil sample underwent redox reactions with a part of oleylammonium iodide (OLAM-I) in advanced. Then, the halogen exchange occurred between the added CsPbBr3 NCs and the iodide ions from the residual OLAM-I. The resulted wavelength-shift of the fluorescence emission reflects the peroxides number in the edible oil sample. Under the UV light excitation at 365 nm, the apparent color of the photoluminescence could directly be compared with a Color Chart to determine and qualify the peroxide number. Using the approach, the visual detection of the perox-ide number of edible oil samples on site could be realized and the detection process only takes about 15 minutes, which is conven-ient and accurate.