The graphene–chitosan composite film modified glassy carbon electrode (GCE) was fabricated and used to determine 4-aminophenol (4-AP). In 0.1 M pH 6.3 phosphate buffer solution , the redox peak currents of 4-AP increased significantly and the peak-to-peak separation decreased greatly at graphene–chitosan composite film modified GCE compared with bare GCE and chitosan modified GCE, indicating that graphene possessed electrocatalytic activity towards 4-AP. The experimental conditions were optimized and the kinetic parameters were investigated. The oxidation mechanism was discussed. Under the optimal experimental conditions, the oxidation peak current was proportional to 4-AP concentration in the range from 0.2 to 550 μM with the correlation coefficient of 0.9930. The detection limit was 0.057 μM (S/N = 3). Using the proposed method, 4-AP was successfully determined in water samples and paracetamol tablets with standard addition method, suggesting that this method can be applied to determine 4-AP in environments and pharmaceuticals.
A biosensor for determination of 3-chloro-1, 2-propandiol (3-MCPD) was developed based on the electrochemically catalytic reduction by hemoglobin (Hb). Hb was concentrated and immobilized with magnetic molecularly imprinted nanoparticles (MMIPs NPs). The MMIP NPs had a core-shell structure, with magnetic Fe 3 O 4 NPs as the core and SiO 2 as the shell. MMIPs NPs were modified on the surface of a magnetic electrode to constitute the Hb enzyme-like sensor. The biosensor could catalyze the electrochemical reduction of 3-MCPD, and a direct electrochemical determination of 3-MCPD could be achieved for the first time. The biosensor, where Hb immobilized with MMIPs NPs had high electrochemical response for 3-MCPD, increased by 37.5% compared with Hb immobilized with magnetic non-imprinted nanoparticle (MNIPs NPs). The biosensor increased the response by 19.56% again under an external magnetic field . The reduction peak current had a linear relationship with 3-MCPD concentration ranging from 1.0 mg·L −1 to 160 mg·L −1 with a detection limit (S/N = 3) of 0.25 mg·L −1 . The biosensor was applied to the determination of 3-MCPD in soy sauce samples successfully with recoveries between 97.4% and 99.6%.
危险品化学品经营许可证（带存储）