Peroxidase Mimicking of Binary Polyacrylonitrile-CuO Nanoflowers and the Application in Colorimetric Detection of H2O2 and Ascorbic Acid

A simple and efficient strategy was developed to synthesize polyacrylonitrile-copper oxide (PAN-CuO) nanoflowers by growing copper oxide nanoneedles on the surface of polyacrylonitrile (PAN) nanoflowers under mild conditions. Fortunately, the obtained PAN-CuO nanoflowers exhibit excellent peroxidase-mimicking activity to catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to form a blue-colored solution with H2O2. The peroxidase-like mechanism originated from the generation of the •OH radical. The PAN-CuO-based colorimetric assay was used to detect H2O2 with a detection limit (LOD) of 0.12 μM in a linear range from 0.5 to 125 μM. The colorimetric method was simple, selective, and sensitive for ascorbic acid (AA) detection in the range of 1–180 μM with a detection limit (LOD) of 0.56 μM. Moreover, the proposed PAN-CuO-based colorimetric assay could be used in the real sample analysis. The peroxidase-like PAN-CuO nanoflowers could provide a versatile catalytic platform for the application of the colorimetric assay method and biomimetic enzyme catalytic systems, and open a new way for detection of AA in biological systems.