羧基化碳纳米管共价层层自组装膜的构建及对多巴胺的电化学检测

Covalent Layer by Layer Self-assembly Carboxylated MWNTs Films for the Detection of Dopamine

本文以乙二胺为连接剂共价层层自组装（LBL）羧基化的多壁碳纳米管（CM-WNTs），并用于多巴胺（DA）的电化学检测。层层自组装过程利用扫描电子显微镜（SEM）和傅里叶变换红外（FT—IR）光谱进行表征。与裸电极相比，修饰电极在较低的电势下对DA表现出优异的电催化特性。修饰层的厚度可通过组装层数进行有效控制，通过电化学实验优化选择组装5层羧基化多壁碳纳米管修饰电极。在0．1mol／LPH-7．0的磷酸盐缓冲液（PBS）中氧化峰电流与DA浓度在6～370μmol／L范围内呈线性关系，检测限（s／N-3）为0．532μmol／L。

This work presents an excellent strategy to assemble a new carboxylic multi-wall carbon nanotubes（CMWNTs） thin film via covalent bond layer by layer self-assembly by using ethylenediamine as an arm linker. Scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize the assembly process. The modified electrode possesses a remarkable electrocatalytic activity towards dopamine at a lower potentials compared with the bare glass carbon electrode. The thickness of the CMWNTs film is easily controlled by changing the numbers of the cycles in the LBL assembly process, which can effectively tune the electrocatalytic activity of the film towards dopamine. The experiments showed that the five layers film has the best electrocatalytic activity. The constructed electrode with five layers showed a good sensitivity of 1. 515 μA/（mol/L）.cm2 to dopamine in the linear range of 6-370μmol/L in p H = 7.0 PBS, with a detection limit of 0. 532 μmol/L（S/N = 3）. Furthermore, the CMWNTs film also showed good selectivity and excellent stability for the determination of dopamine.