离子液体/多壁碳纳米管/壳聚糖修饰电极同时检测多巴胺、抗坏血酸及尿酸的研究

Simultaneous Voltammetric Determination of Dopamine,Ascorbic Acid and Uric Acid by Ionic Liquid/Multi-walled Carbon Nanotubes/Chitosan Composite Electrode

将水溶性离子液体([BMIM]N(CN)2)、多壁碳纳米管(MWCNTs)和壳聚糖(CS)三者结合,修饰在玻碳电极上制备MWCNTs-IL-CS修饰玻碳电极,并研究了多巴胺(DA)、抗坏血酸(AA)、尿酸(UA)在该修饰电极上的电化学行为。扫描电子显微镜图显示,MWCNTs在IL-CS中能良好分散,并形成均一多孔的结构。MWCNTs-IL-CS/GCE对DA、AA、UA均有良好的电催化作用,可有效降低其过电位,提高检测灵敏度。AA-DA、DA-UA的氧化峰电位差分别为208 mV和114 mV。该修饰电极实现了DA、AA和UA的同时测定,DA、AA和UA的线性范围分别为5.00～425μmol/L、0.020～2.25 mmol/L和0.05～10.0 mmol/L,检出限(S/N=3)分别为1.01、10.7、42.9μmol/L。该方法有望用于实际样品中DA、AA和UA的同时快速测定。

An electrochemical sensing platform was developed based on the composite of ionic liquid （ 1-butyl-3-methylimidazolium dicyanamide, [ BMIM ] N （ CN ） 2, IL ）, multi-walled carbon nanotubes（MWCNTs） and polymeric matrix （chitosan, CS）. Scanning electron microscope images showed that MWCNTs had a good dispersibility in the MWCNTs - IL - CS composite and formed a relative smooth film withunique structure. Electrochemical studies indicated that the MWCNTs -IL- CS composite provided a synergistic improvement on the electrochemical oxidation of dopamine（DA） , uric acid（UA） and ascorbic acid （AA） by the decrease of their anodie over-potentials and the enhancement of their amperometric responses. The peak separations between UA and DA, DA and AA were 114 mV and 208 mY, respectively. Additionally, the MWCNTs - IL - CS composite modified i glassy carbon electrode（ MWCNTs- IL- CS/GCE） showed＇ a good analytical performance in the simultaneous determination of DA, AA and UA. The calibration curves of 5.00 - 425 μmol/L, 0. 020 - 2.25 mmol/L and 0. 050 - 10.0 mmol/L, and the detection limits （S/N = 3 ） of 1.01, 10. 7 and 42. 9 μmol/L were obtained for DA, AA and UA, respectively. With good selectivity and sensitivi- ty, the present method is promising in the simultaneous determination of DA, AA anUA in real samples.