Capillary electrophoretic study of amine/carboxylic acid-functionalized carbon nanodots
Capillary electrophoretic study of amine/carboxylic acid-functionalized carbon nanodots
复制标题
胺/羧酸功能化碳纳米点的毛细管电泳研究
DOI：
10.1016/j.chroma.2013.07.035
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发表时间：
2013-08-23
影响因子：
4.1
通讯作者：
Choi, Martin M. F.
中科院分区：
文献类型：
--
作者：
Hu, Qin;Paau, Man Chin;Choi, Martin M. F.
毛细管区带电泳 (CZE) 与紫外吸收和激光诱导荧光检测相结合，已用于研究微波辅助热解柠檬酸 (CA) 和 1,2-乙二胺 (EDA) 合成的碳纳米点 (C-dots) 产品的复杂性。详细研究了运行缓冲液的 pH 值和浓度对碳点 CZE 分离的影响。随后采用最佳的乙酸盐运行缓冲液（30 mM，pH 3.6）来研究反应时间和前体的胺（NH2）与羧酸（COOH）部分的摩尔比对碳点产物中存在的碳点物质的影响。我们的结果证实，通过延长微波辐射时间和优化前驱体中 NH2/COOH 的初始摩尔比可以改善碳点的合成。只有当CA的量超过EDA的量，即NH2/COOH的摩尔比为0.25-0.80时，才能获得带负电的碳点。相比之下，当 EDA 中 NH2 的量（摩尔）等于或大于 CA 中 COOH 的量时，仅形成带正电和中性的碳点物质，推断碳点物质主要被表面附着的铵和酰胺部分覆盖。这项工作突出了 CZE 的优点，可以识别所制备的碳点产品的成分，该成分很大程度上取决于 NH2/COOH 的摩尔比。预计我们的 CZE 方法将为优化合成条件以生产所需组成的特定碳点开辟一条新途径。 (C) 2013 Elsevier B.V. 保留所有权利。
Capillary zone electrophoresis (CZE) coupled with UV absorption and laser-induced fluorescence detections has been applied to study the complexity of carbon nanodots (C-dots) products synthesized with microwave-assisted pyrolysis of citric acid (CA) and 1,2-ethylenediamine (EDA). The effects of pH and concentration of run buffer on the CZE separation of C-dots are studied in detail. The optimal acetate run buffer (30 mM, pH 3.6) is subsequently employed to investigate the effect of reaction time and mole ratio of amine (NH2) to carboxylic acid (COOH) moieties of the precursors on the C-dots species present in C-dots products. Our results confirm that the synthesis of C-dots could be improved by lengthening the microwave irradiation time and optimizing the initial mole ratio of NH2/COOH in the precursors. Negatively charged C-dots are obtained only when the amount of CA exceeds that of EDA, i.e., the mole ratio of NH2/COOH is 0.25-0.80. By contrast, when the quantity (mole) of NH2 in EDA is equal to or larger than that of COOH in CA, only positively charged and neutral C-dots species are formed, inferring that the C-dots species are predominantly covered by the surface-attached ammonium and amido moieties. This work highlights the merit of CZE to identify the composition of an as-prepared C-dots product which is pretty much dependent on the mole ratio of NH2/COOH. It is anticipated that our CZE methodology will open a new avenue in optimizing the synthetic conditions for producing specific C-dots of desired composition. (C) 2013 Elsevier B.V. All rights reserved.