聚中性红/纳米二氧化硅复合修饰电极直接测定抗坏血酸

Poly(Neutral Red) electrogenerated on a silica nanoparticle modified electrode for direct determination of ascorbic acid

用滴涂法和电化学聚合法制备了聚中性红/纳米二氧化硅修饰电极(PNR/nano-SiO2/GCE),并用循环伏安法和交流阻抗法研究了修饰电极表面的电化学行为。实验表明,该修饰电极对抗坏血酸(AA)表现出良好的电催化氧化性能,探讨了复合修饰电极协同增效作用的机理。用线性扫描伏安法研究了AA浓度与峰电流之间线性关系,在pH2.0的磷酸盐缓冲溶液中,AA氧化峰电流在1.8×10-6～5.0×10-3mol/L浓度范围内呈良好的线性关系,检出限为5.4×10-7mol/L(S/N=3)。该修饰电极制备简单,可用于药品及果蔬食品中抗坏血酸的直接测定。

A poly（neutral red） electrogenerated on silica nanoparticle modified glassy carbon electrode（PNR/nano-SiO2/GCE） was fabricated by drop-coating and electropolymerization.The electrochemical behaviors of PNR/nano-SiO2/GCE were investigated by cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS）.The modified electrode showed good electrocatalysis towards the oxidation of ascorbic acid（AA）,which indicated that a synergistic effect existed between the polymer and nanoparticles.The catalytic peak current obtained by linear sweep voltammetry（LSV） in phosphate buffer（pH 2） was linearly dependent on the concentration of AA in the range of 1.8×10-6 ~5×10-3 mol/L with a detection limit of 5.4×10-7 mol/L（S/N=3）.The proposed electrode could be applied to direct-detection of AA in medicine and food samples.