2D CoOOH nanosheets as oxidase mimic for the colorimetric assay of sulfite in food†
Abstract
Here, we report a rapid, sensitive and selective colorimetric assay for sulfite (SO32−) based on the intrinsic oxidase-like activity of 2D cobalt oxyhydroxide nanosheets (CoOOH NSs). The 2D CoOOH nanozyme could directly oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into blue products (TMBox) in an aerobic solution without H2O2. Interestingly, the presence of SO32− could effectively inhibit the CoOOH NS–O2–TMB reaction system and thus caused changes in color and absorbance, which facilitated a colorimetric sensor for sulfite. After optimizing detection conditions, a facile and robust approach was developed for SO32− detection in food.