Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 , F-35000 Rennes , France.
Anal Chem. 2019 Feb 19;91(4):2797-2804. doi: 10.1021/acs.analchem.8b04671. Epub 2019 Feb 5.
An electrode modified by a Ti complex in Nafion was used in the electrochemical detection of nitroaromatic compounds (NACs). The catalyst reduced nitroaromatic groups by a six-electron process with a high apparent rate constant, k, which was estimated to be at least 19 000 mol L s by simulation of the first step of the cathodic reduction of 4-nitrophenylacetic acid, which was used as model molecule. The modified electrode was prepared and optimized in terms of Nafion and catalyst concentrations. In the chosen analytical medium, the Ti-catalyst-containing electrode showed good stability in the presence of nitro species. A standard deviation around 15% was calculated on the analysis performed with 28 different modified electrodes, which could be expected for a drop-coating process. We show that the modified electrode detects several nitroaromatic compounds such as nitrophenols, mononitroaniline, and dinitrotoluene with detection limits ranging from 1 × 10 to 9 × 10 g L (0.2 × 10 to 5.1 × 10 mol L). As an interesting feature, the sensor exhibits good selectivity toward NAC detection because titanocene does not catalyze the reduction of nitroaliphatic compounds.
一种在 Nafion 中用钛配合物修饰的电极被用于电化学检测硝基芳香族化合物（NACs）。该催化剂通过六电子过程将硝基芳香族基团还原，表观速率常数 k 很高，通过模拟 4-硝基苯乙酸的阴极还原的第一步来估计 k 值至少为 19000molLs，4-硝基苯乙酸被用作模型分子。该修饰电极在 Nafion 和催化剂浓度方面进行了制备和优化。在所选的分析介质中，含有钛催化剂的电极在硝基物质存在下表现出良好的稳定性。用 28 个不同修饰电极进行的分析得出了约 15%的标准偏差，这对于滴涂过程来说是可以预期的。我们表明，修饰电极可以检测几种硝基芳香族化合物，如硝基酚、单硝基苯胺和二硝基甲苯，检测限范围为 1×10 至 9×10 g L（0.2×10 至 5.1×10 mol L）。作为一个有趣的特点，该传感器对 NAC 的检测具有良好的选择性，因为钛茂不会催化硝基脂肪族化合物的还原。
