Keggin型磷钨酸/2-氨基吡啶聚合膜修饰电极的电化学性质及对维生素B2的电催化

制备了Keggin型磷钨酸/2-氨基吡啶电聚合复合膜修饰电极，研究了该复合膜修饰电极的电化学性质。结果表明，在BR缓冲溶液中，该复合膜修饰电极显示出3对氧化还原峰，对应于表面电沉积的磷钨酸的电化学作用，其电化学行为受表面吸附控制。该电极对维生素B2（VB2）具有良好的电催化作用，根据VB2的电化学行为，推断出了可能的电极反应机理，计算出VB2在该电极上的电荷转移系数为0.357，电荷转移速率常数为0.042 s-1，推断其在该电极上的行为为准可逆过程。在2.4×10-6~1.0×10-4 mol/L和1.0×10-4~5.5×10-4 mol/L 范围内峰电流与VB2浓度呈良好的线性关系，其检出限为1.4×10-6 mol/L。该电极显示出良好的稳定性和重现性，用于复合维生素药片中VB2含量的测定，结果满意。

Investigation of Electrochemical Properties of Keggin-type Phosphotungstic Acid/2-Amino Pyridine Electropolymerized Modified Electrode and Its Electrocatalysis Towards Vitamin B2

A novel Keggin-type phosphotungstic acid H7P(W2O7)6]/2-amino pyridine electropolymerization(PW/PAP) modified glassy carbon electrode was fabricated by electrodepositing H7P(W2O7)6] onto 2-amino pyridine electro-polymerized glassy carbon electrode.The electrochemical behaviors of PW/PAP modified electrode were investigated by cyclic voltammetry.It is found that there are three redox peaks appeared in the potential range from-0.8 V to 0.2 V in BR buffer solution.The modified electrode showed a good electrocatalysis towards the electro-oxidation of vitamin B2(VB2).The electrochemical behavior of VB2 was surface-controlled.The electron transfer coefficient and rate constant were calculated to be 0.357 and 0.042 s-1,respectively,indicating that the electrochemical reaction of VB2 was a quasi-reversible process.Under the optimal conditions,there was a good linear relationship between the peak currents and VB2 concentrations in the concentration range of 2.4×10-6-1.0×10-4mol/L and 1.0×10-4-5.5×10-4 mol/L,with a detection limit of 1.4×10-6 mol/L.The composite electrode had good stability and reproducibility,and was used in the determination of VB2 in composite vitamin tablets with satisfactory results.