Oxidase Mimetic Activity of a Metalloporphyrin-Containing Porous Organic Polymer and Its Applications for Colorimetric Detection of Both Ascorbic Acid and Glutathione

The selective detection of ascorbic acid (AA) and glutathione (GSH) is very significant for dietary guidance and health monitoring. Herein, we prepared a metalloporphyrin-containing porous organic framework (Co-POP) via a facile Friedel–Crafts reaction. Co-POP was able to catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue substrate (ox-TMB) in the role of dissolved oxygen. The best catalytic performance of Co-POP was realized at 25 °C and pH 4 according to the optimized experiments. Because of the high oxidase-like activity of Co-POP, a simple and sensitive colorimetric assay was established for the determination of AA and GSH in a wide range. The detection limit (LOD) of AA and GSH was calculated to be 1.60 and 0.71 μM, respectively. Finally, the application of the colorimetric sensor for AA and GSH detection in real samples (fruits and diluted serum) was also evaluated, suggesting its great potential for biocatalysis and biosensing.