Wavelength-Shift-Based Colorimetric Sensing for Peroxide Number of Edible Oil Using CsPbBr3 Perovskite Nanocrystals

The peroxide number of edible oil relates to its quality. The classical determination methods for the peroxide number are still unsatisfactory due to their complexity and poor reproducibility in the analytical process and their 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 advance. Then, the halogen exchange occurred between the added CsPbBr3 NCs and the iodide ions from the residual OLAM-I. The resulting wavelength shift of the fluorescence emission reflects the peroxide number in the edible oil sample. Under the ultraviolet 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 peroxide number of edible oil samples on site could be realized. The detection process takes only ∼15 min and is convenient and accurate.