Abstract The quantification of surface groups is a key characterization for different carbon materials as their behavior in colloidal dispersion, their interaction with proteins, drugs or polymers as well as their aggregation behavior strongly depend on the type and number of surface groups. Some of the most challenging groups are those containing oxygen as the typical characterization methods do not allow for a highly sensitive and reproducible quantification of carboxylic, lactonic and alcoholic groups. The only known wet-chemical method that is able to yield quantitative results is the Boehm titration. However, this method is also known to be extremely demanding regarding procedure compliance, requires large amounts of sample, and leads to rather large standard deviations. Here we report on a significantly improved titration method for the quantification of oxygen containing surface groups. All methodical aspects like sample preparation, reaction time, filtration medium, volumetric and gravimetric methods have been optimized, leading to the detection of carboxylic, lactonic and alcoholic groups with a standard deviation of ±1 μmol/g while using only small amounts of sample material. The method has been successfully applied on a broad variety of hydrophilic and hydrophobic carbon materials including nanodiamond, partially graphitized nanodiamond, multiwall carbon nanotubes and acetylene black.

中文翻译：

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碳纳米材料上氧化表面基团的高灵敏度和可重复定量

摘要 表面基团的量化是不同碳材料的关键表征，因为它们在胶体分散中的行为、它们与蛋白质、药物或聚合物的相互作用以及它们的聚集行为在很大程度上取决于表面基团的类型和数量。一些最具挑战性的基团是含氧基团，因为典型的表征方法不允许对羧基、内酯基和醇基进行高度灵敏和可重复的量化。唯一已知的能够产生定量结果的湿化学方法是 Boehm 滴定。然而，众所周知，这种方法对程序合规性要求极高，需要大量样本，并导致相当大的标准偏差。在这里，我们报告了一种显着改进的滴定方法，用于量化含氧表面基团。样品制备、反应时间、过滤介质、体积和重量方法等所有有条理的方面都得到了优化，从而在仅使用少量样品材料的情况下以 ±1 μmol/g 的标准偏差检测羧基、内酯和醇基团. 该方法已成功应用于多种亲水性和疏水性碳材料，包括纳米金刚石、部分石墨化纳米金刚石、多壁碳纳米管和乙炔黑。内酯基和醇基的标准偏差为 ±1 μmol/g，同时仅使用少量样品材料。该方法已成功应用于多种亲水性和疏水性碳材料，包括纳米金刚石、部分石墨化纳米金刚石、多壁碳纳米管和乙炔黑。内酯基和醇基的标准偏差为 ±1 μmol/g，同时仅使用少量样品材料。该方法已成功应用于多种亲水性和疏水性碳材料，包括纳米金刚石、部分石墨化纳米金刚石、多壁碳纳米管和乙炔黑。