Fe, Cu Co-Doped Carbon Nanosheets for Electrochemical-Colorimetric Detection of Acetaminophen

In this paper, iron–copper bimetallic nanosheet materials (FeCu/CNS) were prepared using hydrothermal and pyrolysis methods to develop a dual-mode electrochemical and colorimetric sensing platform for detecting acetaminophen (ACM). The glassy carbon electrode (GCE) was modified with FeCu/CNS to enhance its electrocatalytic activity and develop an electrochemical sensor for detecting ACM. The linear range of the sensor was 0.01–7 × 10–6 mol/L, and the detection limit (LOD) was 2.5 × 10–8 mol/L. In addition, FeCu/CNS possesses an efficient peroxidase-like activity that converts colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into a blue oxidized state product (oxTMB) in the presence of H2O2, which exhibits a characteristic absorption peak around 652 nm. However, ACM has reducing properties and can reduce oxTMB to TMB, thereby reducing the intensity of the characteristic absorption peak of oxTMB. Based on this principle, a colorimetric sensor was constructed for the detection of ACM, which had a linear range of 0.5–1625 × 10–6 mol/L and an LOD of 2.63 × 10–6 mol/L. Compared with other single methods, the method exhibited a wider linear range and lower detection limit, confirming the complementary and superior nature of the dual-mode sensor designed in this paper for ACM detection. Meanwhile, the detection of ACM in human serum was also carried out with satisfactory results.