壳聚糖/多壁碳纳米管复合膜电化学手性识别色氨酸对映异构体

摘要

The dispersed multiwalled carbon nanotubes with carboxyl (f-MWCNTs) were firstly dropped on the glass carbon electrode to allow a f-MWCNTs menbrance formed on the electrode surface,then chitosan(CS) was electrodeposited on the surface of the eletrode via potentiostatic method to develop a CS/f-MWCNTs/GCE which was used for the chiral recognition of tryptophan enantiomers.The surface morphology of the eletrode was characterized via scanning electron microscopy (SEM).Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behavior difference of the modified electrode.Differential pulse voltammetery (DPV) was employed to investigate the stereospecific recognition of tryptophan (Trp) enantiomers with a separation coefficient of 2.38.The results showed that the CS/f-MWCNTs/GCE displayed a more strong DPV response for L-Trp than that for D-Trp in the linear range of 8.0 × 10-6-4.0 × 10-3 mol/L with a detection limit of 5.0 × 10-6 mol/L(S/N =3).Meanwhile,it provided a beneficial reference for the discrimination of other chiral enantiomers.%采用滴涂方式将羧酸化多壁碳纳米管(f-MWCNTs)修饰于玻碳电极(GCE)表面成膜,然后恒电位法在上述修饰电极表面电沉积壳聚糖(CS)膜,形成CS和f-MWCNTs复合膜修饰电极(CS/f-MWCNTs/GCE),并用于色氨酸(Trp)对映异构体的手性识别.采用扫描电子显微镜(SEM)表征了修饰电极表面形貌的差异,电化学阻抗(EIS)和循环伏安法(CV)研究修饰电极的电化学行为差异.差分脉冲伏安法(DPV)用于区别色氨酸(Trp)对映异构体,分离系数可达2.38.研究发现该修饰电极对L-Trp的DPV响应信号强于D-Trp,检测的线性范围为8.0×10-6～4.0×10-3 mol/L,检出限(S/N=3)为5.0×10-6 mol/L.该方法简单、经济、快速,对发展其它手性化合物的检测方法提供了参考.