Multi-channel colorimetric detection of thiram in food and water samples via activated dual enzyme-like activities of Cu2.

Thiram (Thr) residues pose potential risks to ecological environment and human health. Herein, a simple multi-channel colorimetric assay for Thr detection was proposed. Cu2+ served as the colorimetric probe, and coordinated with Thr, forming Cu2+-Thr complex with satisfactory oxidase (OXD)-like and laccase (LAC)-like activity. The catalytic kinetics of Cu2+-Thr complex well fitted Michaelis-Menten model. Leveraging Thr activated OXD and LAC-like activities of Cu2+, colorimetric assays for Thr detection were developed. The detection range and limit of detection of this method were comparable to those methods involving nanomaterials. By integrating smartphone with test papers and test swabs, two portable sensing platforms were developed to achieve on-site detection of Thr. The concentrations of Thr in food and water samples were successfully determined via multiple channels with satisfactory recoveries and relative standard deviation. The simple and low-cost multi-channel colorimetric sensing platforms showed potential for food safety analysis and environmental monitoring.