Sensitive and selective electrochemical sensing of L-cysteine based on a caterpillar-like manganese dioxide-carbon nanocomposite.
Sensitive and selective electrochemical sensing of L-cysteine based on a caterpillar-like manganese dioxide-carbon nanocomposite.
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DOI：
10.1039/c0cp00980f
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发表时间：
2011-01
期刊：
影响因子：
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通讯作者：
Chunhui Xiao;Jinhua Chen;Bo Liu;X. Chu;Liang Wu;S. Yao
中科院分区：
文献类型：
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作者：
Chunhui Xiao;Jinhua Chen;Bo Liu;X. Chu;Liang Wu;S. Yao
通过碳纳米管（CNTs）与高锰酸盐离子的直接氧化还原反应，首次合成了一种新型的一维毛毛虫状二氧化锰-碳（MnO（2）-C）纳米复合材料。所制备的纳米MnO（2）-C复合材料主要由ε-MnO（2）纳米片组成，具有独特的微观结构、高的比表面积（200 m2 g-1）和良好的导电性。通过直接电化学共沉积法将纳米MnO（2）-C复合物添加到玻碳电极上，发现该复合物对L-半胱氨酸的电氧化表现出优异的催化活性，这是因为L-半胱氨酸的-SH基团与固体MnO（2）之间发生了特异性的相互作用，形成了表面复合物。用电流法在MnO（2）-C/chitosan/GC（MnO（2）-C/chit/GC）电极上测定了L-半胱氨酸。在最佳实验条件下，L-半胱氨酸的检测响应快（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），检测限为22 nM。MnO（2）-C/Chit/GC电极具有良好的稳定性（1个月后响应信号没有任何下降）和良好的抗干扰性，如谷胱甘肽和其他可氧化的氨基酸（色氨酸、酪氨酸、L-赖氨酸和蛋氨酸）。
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).