CuO nanorod-decorated hemin-graphene with enhanced peroxidase-mimicking performance for the colorimetric and electrochemical determination of 4-aminophenol with a smartphone

, an enhanced electrochemical signal of TMB was generated. Upon the addition of 4-AP, the catalytic performance of CuO/H-Gr in the oxidation of TMB was significantly reduced, leading to a decrease in colorimetric and electrochemical signals. Based on this, a dual-mode sensor for the detection of 4-AP was developed. The linear response ranges for colorimetric and electrochemical sensors are 1.00-200 μM and 0.0100-300 μM, with detection limits of 0.687 μM and 0.00756 μM, respectively. Real water samples were tested to estimate the feasibility of the dual-mode sensor, and the recoveries were found to be consistent with those obtained by high-performance liquid chromatography. In addition, a smartphone-based assay was used to evaluate the levels of 4-AP, which opened a new path for on-site detection.