盐酸伪麻黄碱在多壁碳纳米管修饰玻碳电极上的电催化氧化及其电化学动力学性质  

Electrocatalytic Oxidation of Pseudoephedrine Hydrochloride at Multi-wall Carbon Nanotube Modified Glassy Carbon Electrode and Its Electrochemical Kinetics

作　　者：孙玉琴[1] 犹卫[1] 高作宁[1] 

机构地区：[1]宁夏大学能源化工重点实验室,化学化工学院,银川750021

出　　处：《应用化学》2008年第1期58-62,共5页Chinese Journal of Applied Chemistry

基　　金：宁夏高等学校科学研究基金(200623);宁夏大学自然科学基金(ZR0641)项目资助

摘　　要：研究了盐酸伪麻黄碱（Pseudoephedrine hydrochloride，PSE）在多壁碳纳米管修饰玻碳电极（MWCNT／GCE）上的电化学行为。结果表明，PSE在GCE上的直接电化学氧化十分迟缓，无氧化峰出现，表明PSE在GCE上过电位较高，不易直接发生氧化反应。在MWCNT／GCE上PSE氧化电流随电位正移逐渐增大．在0．902 V处出现1个不可逆氧化峰，表明MWCNT／GCE对PSE直接电化学氧化具有良好的催化作用。研究了实验条件对PSE电化学行为影响。表明PSE在酸性条件下无氧化峰出现，在中性及碱性条件下出现不可逆氧化峰；在10～1000mV／s扫描速率范围内氧化峰电流Ipa与扫描速度平方根（v^1/2）成正比，表明PSE在MWC—NT／GCE上的电化学氧化反应是一个受扩散控制的电极过程。同时测定了PSE电催化氧化电极过程动力学参数：扩散系数D=3．10×10^-6cm^2／s，电子转移系数α=0．94，电极反应速率常数kf=1．48×10^-3／s。利用稳态电流-时间曲线测定了电流响应时间和浓度关系。结果表明，PSE稳态电流响应信号随其浓度成比例增长，响应时间〈5s，最低响应浓度为1×10^-5mol／L。方法检出限低，灵敏度高，可用于PSE电化学定量测定方法。Electrochemical behavior of pseudoephedrine hydrochloride （PSE） on multi-wall carbon nanotube modified glassy carbon electrode（MWCNT/GCE） was investigated by cyclic voltammetry（CV）. The experimental results showed that the direct electrochemical oxidation of PSE was sluggish on GCE, with no oxidation peaks appearing, indicating that PSE has a high overpotential and can not be directly oxidized. However, on MWCNT/GCE, its oxidation current increased with the potential shifting positive, and an irreversible oxidation peak appeared at 0. 902 V, which indicated that MWCNT/GCE can catalyze the electrochemical oxidation of PSE very well. The influence of experimental conditions on the electrochemical behavior of PSE was also studied. No oxidation peaks appeared for PSE at pH 〈 7.0 ; whereas at pH 〉 7.0, an anodic oxidation peak appeared, which was a diffusion-limited electrode reaction process; at the same time the diffusion coefficient D, electron transfer coefficient a, and the electrode reaction rate constant kf were determined to be 3.10 × 10^-6 cm^2/s, 0.94, and 1. 48 × 10^-3/s, respectively. The experimental results of the amperometric response to time showed that current signal of the MWCNT/GCE was proportional to the PSE concentration, and the response time was less than 5 seconds, and the response concentration limit was 1 × 10^-5 mol/L. The method can be used in PSE electrochemical quantitative determination with low detection limit and high sensitivity.

关 键 词：盐酸伪麻黄碱 碳纳米管修饰电极 电催化氧化 电化学动力学 

分 类 号：O647[理学—物理化学]