Smartphone-assisted ultrasensitive colorimetric strategy based on Cu-CN single-atom nanozyme for acrylamide detection in fried food.

Herein, a novel colorimetric strategy based on Cu-CN single-atom nanozymes (Cu-CN SANs) is constructed for acrylamide detection. Cu-CN SANs exhibit excellent oxidase mimetic activity, which can efficiently catalyze the oxidation of substrate TMB to produce a blue product. GSH inhibits the oxidation of TMB by Cu-CN SANs. However, the addition of acrylamide enables the efficient thiolene Michael addition reaction between GSH and acrylamide, thus restoring the oxidation of TMB by Cu-CN SANs. The developed method enables acrylamide detection within a linear range of 0.05-15 μM, with a low detection limit (LOD) of 15.4 nM and a relative standard deviation (RSD%) below 4.3 %. When applied to real samples, the biosensor achieved satisfactory recoveries of 95.3-103.6 % for acrylamide analysis in bread, cookies, and chips samples. Additionally, integrating the sensor with a smartphone enabled on-site detection, yielding an LOD of 146 nM.