基于多壁碳纳米管-氧化钨纳米复合材料的多巴胺电化学传感器

Electrochemical Dopamine Sensor Based on Multi-Walled Carbon Nanotubes-Tungsten Oxide Nanocomposites

通过电化学沉积法制备多壁碳纳米管-氧化钨(MWCNTs-WOx)纳米复合材料,利用场发射扫描电子显微镜(SEM)和X射线光电子能谱分析仪(XPS)对其形貌和组成进行表征。制备了复合材料修饰的玻碳电极,采用电化学阻抗(EIS)技术对修饰电极进行表征。采用循环伏安(CV)法研究了多巴胺(DA)在修饰电极上的电化学行为,以差分脉冲伏安(DPV)法建立DA检测方法。结果表明,在p H=6.5磷酸盐缓冲液(PBS)中,MWCNTs-WOx纳米复合材料对多巴胺有明显的电催化作用。在优化的条件下,氧化峰电流与DA浓度在0.05~1.00 mmol/L范围内呈良好的线性关系,检出限为17μmol/L(S/N=3)。此电化学传感器具有良好的重现性、选择性及较强的抗干扰能力,尿酸(UA)不影响DA的定量检测。将此方法用于盐酸多巴胺注射液的含量检测,效果良好。

Multi-walled carbon nanotubes-tungsten oxide(MWCNTs-WOx)nanocomposites were fabricated on glassy carbon electrode(GCE)through a simple electrodeposition method,in which WOx were fabricated on MWCNTs.The morphology and constitution were characterized by field emission scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).Electrochemical characterization of modified electrode was done by electrochemical impedance spectroscopy(EIS).The cyclic voltammogram(CV)method was adopted to investigate the electrochemical behavior of dopamine(DA)on MWCNTs-WOx-modified glassy carbon electrode,and a new detection method for DA was developed by differential pulse voltammetry(DPV).The results showed that MWCNTs-WOx nanocomposites had obvious electrocatalytic effect on DA in phosphate buffer solution(pH=6.5).Under the optimized experimental conditions,the DA peak current demonstrated a good linear relationship with concentration in the range of 0.05-1.00 mmol/L,and the detection limit was 17μmol/L(S/N=3).Effects of different experimental parameters on the response current of the modified electrode were investigated,and it was found that the prepared electrochemical sensor displayed good reproducibility,high selectivity and strong anti-interference ability.UA did not interfere with the detection of DA.A new electrochemical method for the quantitative determination of DA was established and successfully applied to the determination of dopamine hydrochloride injection samples.