State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
Phys Chem Chem Phys. 2011 Jan 28;13(4):1568-74. doi: 10.1039/c0cp00980f. Epub 2010 Nov 23.
A novel one-dimensional (1-D) caterpillar-like manganese dioxide-carbon (MnO(2)-C) nanocomposite has been synthesized by a direct redox reaction between carbon nanotubes (CNTs) and permanganate ions for the first time. The as-prepared nanostructured MnO(2)-C composite mainly consisting of ε-MnO(2) nanoflakes had a unique microstructure, high specific surface area (200 m(2) g(-1)) and favourable conductivity. The nanostructured MnO(2)-C composite, added as a modification to the glassy carbon (GC) electrode via a direct electrochemical co-deposition process with a chitosan hydrogel, was found to exhibit excellent catalytic activity toward L-cysteine electro-oxidation because the specific interaction between the -SH group of L-cysteine and solid MnO(2) occurred to form surface complexes. A determination of L-cysteine at the MnO(2)-C/chitosan/GC (MnO(2)-C/chit/GC) electrode was carried out by amperometric measurement. Under the optimum experimental conditions, the detection response for L-cysteine was fast (within 7 s). The logarithm of catalytic currents shows a good linear relationship with that of the L-cysteine concentration in the range of 0.5-680 μM (R = 0.9986), with a low detection limit of 22 nM. The MnO(2)-C/Chit/GC electrode exhibited excellent stability (without any decrease of the response signal after 1 month) and admirable resistance against interference like glutathione and other oxidizable amino acids (tryptophan, tyrosine, L-lysine and methionine).
一种新型一维（1-D）毛毛虫状的二氧化锰-碳（MnO2-C）纳米复合材料，通过碳纳米管（CNTs）和高锰酸盐离子之间的直接氧化还原反应首次被合成。所制备的纳米结构 MnO2-C 复合材料主要由ε-MnO2 纳米片组成，具有独特的微观结构、高比表面积（200 m2 g-1）和良好的导电性。通过与壳聚糖水凝胶的直接电化学共沉积过程，将纳米结构的 MnO2-C 复合材料添加到玻璃碳（GC）电极作为修饰物，被发现对 L-半胱氨酸的电氧化具有优异的催化活性，因为 L-半胱氨酸的-SH 基团与固体 MnO2 之间发生特定相互作用，形成表面配合物。在 MnO2-C/壳聚糖/GC（MnO2-C/Chit/GC）电极上通过安培测量进行 L-半胱氨酸的测定。在最佳实验条件下，L-半胱氨酸的检测响应速度很快（在 7 s 内）。催化电流的对数与 L-半胱氨酸浓度在 0.5-680 μM 范围内呈良好的线性关系（R = 0.9986），检测限低至 22 nM。MnO2-C/Chit/GC 电极表现出优异的稳定性（1 个月后响应信号没有任何下降），并且对谷胱甘肽和其他可氧化氨基酸（色氨酸、酪氨酸、L-赖氨酸和蛋氨酸）等干扰具有良好的抗干扰能力。
