Abstract The internal and external surface of smectite was successfully modified by triethoxyoctylsilane. The material was first submitted to a soft acid pre-treatment to provide abundant and available hydroxyl functions capable of reacting with the silane. Physicochemical characterizations (XRD, TGA, solid-state 13C NMR, FTIR and specific surface analysis) showed that HCl treatment led to the moderate modification of the clay structures. This resulted in a slight increase of d001 (from 10.1 A to 11.1 A) and the specific surface area (from 102.8 m2 g−1 to 113.9 m2 g−1). Silane grafting was more effective in ethylene glycol (EG) as solvent compared to toluene, as showed by the high amount of silane present in the functionalized clay and the significant increase of d001 following grafting (14.9 A). On the other hand, despite the high amount of grafted silane, the electrochemical characterization clearly showed that the clay still retains some cation exchange capacity, although negligible. The materials were then evaluated for their performance as modifiers of a carbon paste electrode applied to the electroanalysis of glyphosate, certainly the most used pesticide in the world. The material functionalized in EG was found to be the most efficient. After the optimization of some experimental parameters (5% of modifier and pH of the electrolytic solution set at 6.8), a calibration curve was plotted in the concentration range of 10 μM to 100 μM. A sensitivity of 0.15 μA μM−1 and a detection limit of 0.98 μM were obtained. This electrode presents the advantage of being able to perform direct detection of glyphosate and offers exceptional reproducibility (variation of about 1.1% for eight consecutive measurements). It was therefore successfully used for the determination of trace amount of glyphosate present in contaminated soil.

中文翻译：

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在酸处理的蒙脱石层间接枝亲有机硅烷：在草甘膦直接电化学检测中的应用

摘要 三乙氧基辛基硅烷成功地对蒙脱石内外表面进行了改性。该材料首先进行软酸预处理，以提供大量可用的羟基官能团，能够与硅烷反应。物理化学表征（XRD、TGA、固态 13C NMR、FTIR 和比表面分析）表明 HCl 处理导致粘土结构的适度改性。这导致 d001（从 10.1 A 到 11.1 A）和比表面积（从 102.8 m2 g-1 到 113.9 m2 g-1）略有增加。与甲苯相比，在作为溶剂的乙二醇 (EG) 中，硅烷接枝更有效，如官能化粘土中存在的大量硅烷和接枝后 d001 的显着增加 (14.9 A) 所示。另一方面，尽管有大量接枝硅烷，电化学表征清楚地表明粘土仍然保留了一些阳离子交换能力，尽管可以忽略不计。然后评估这些材料作为碳糊电极改性剂的性能，该电极应用于草甘膦的电解分析，草甘膦无疑是世界上最常用的农药。发现在 EG 中官能化的材料是最有效的。对一些实验参数（改性剂的5%，电解液的pH值设置为6.8）进行优化后，在10 μM至100 μM的浓度范围内绘制校准曲线。获得了 0.15 μA μM-1 的灵敏度和 0.98 μM 的检测限。该电极的优势在于能够直接检测草甘膦，并提供出色的重现性（连续八次测量的变化约为 1.1%）。因此，它成功地用于测定受污染土壤中存在的痕量草甘膦。