不同尺寸球形纳米金粒子修饰电极在高浓度抗坏血酸共存下选择性测定多巴胺

Different Sizes of Spherical Gold Nanoparticles Modified Electrodes for Selective Determination of Dopamine in the Presence of High Concentration of Ascorbic Acid

本文制备了直径分别为5nm、20nm和50nm的球形纳米金颗粒(AuNPs),通过一步恒电位沉积法将AuNPs修饰到碳纤维微电极的表面上以获得AuNPs改性的碳纤维微电极(AuNPs/CFME),并研究了电极修饰前后对多巴胺(DA)、去甲肾上腺素(NE)、抗坏血酸(AA)、K_3[Fe(CN)_6]的电化学响应。结果表明,AuNPs/CFME对带正电荷的儿茶酚胺类神经递质具有明显的电催化作用,对带负电荷的物质具有明显的屏蔽作用。球形AuNPs的尺寸越小,其催化屏蔽效果越好。在高浓度AA共存下,差分脉冲伏安法(DPV)峰值电流与DA浓度在0.1~10.0μmol/L的范围呈线性相关,检出限(S/N=3)为0.013μmol/L。本文开发了一种简便高效的方法,用于选择性检测带正电的DA并屏蔽荷负电物质,已将其应成功应用于小鼠血清样品中高浓度AA共存下DA的选择性测定。

In this paper,the spherical gold nanoparticles with diameters of 5 nm,20 nm,and 50 nm were prepared.The gold nanoparticles were deposited on the surface of carbon fiber microelectrodes by one-step potentiostatic deposition to obtain nanogold-modified carbon fiber microelectrodes(AuNPs/CFME),and electrochemically characterized the electrodes before and after modification.The electrochemical behaviors of dopamine,norepinephrine,ascorbic acid,potassium ferricyanide were studied on the microelectrodes before and after modification.The results show that AuNPs/CFME has obvious electrocatalytic effect on catecholamines with positive charge,and has obvious shielding effect on negatively charged substances.The smaller the size of spherical gold nanoparticles,the better the catalytic shielding effect.Under optimum conditions,the differential pulse voltammetry(DPV)peak current and the concentration of dopamine with high concentration of ascorbic acid display a linear range of 0.1μmol/L to 10μmol/L with the detection limit of 0.013μmol/L(S/N=3).This work provides a simple and easy approach to selectively detect positively charged substance and shielding the negatively charged substance.In particular,they have been applied to the selective determination of dopamine in the presence of higher concentrations of ascorbic acid in real mouse serum sample,showing excellent analytical performance.