A colorimetric sensor array for rapid discrimination of edible oil species based on a halogen ion exchange reaction between CsPbBr3 and iodide

Abstract

Peroxides in edible oils, whose amounts are measured using the peroxide value, are closely related to human health. Long-term consumption of edible oils with high peroxide values can lead to a variety of human diseases, which highlights the significance of examining oil types and their corresponding peroxide values. For identifying a wide range of edible oils, we established a colorimetric sensor array based on the halogen ion exchange between CsPbBr₃ and two iodides (octadecylammonium iodide (ODAI) and ZnI₂). Different kinds of edible oils contain distinct peroxidic substances that have the distinct ability to oxidize iodides. After specific types of edible oils react with excess iodides (ODAI and ZnI₂), different amounts of residual iodides are left for further halogen exchange with CsPbBr₃, resulting in various colorimetric responses, measured in RGB (red/green/blue) values, under fluorescent light. Based on RGB pattern analysis as fingerprints using two anion exchangers (ODAI and ZnI₂), our proposed colorimetric sensor array was proved by linear discriminant analysis (LDA) to have an ability to accurately distinguish edible oils at a minimal volumetric concentration of 6.67% in seven real samples.