Water-soluble carbon nanodots (CND) were synthesized under microwave irradiation from glutamic acid or glutamic acid–boric acid mixture. The CNDs were collected in an aqueous solution through size fractionation by centrifugal filtration. The CNDs thus prepared were subjected to characterization by capillary electrophoresis (CE). A peak signal of anionic substance was detected in the electropherogram, and it was found to be a major component of the CNDs. The effective electrophoretic mobility of the major component was almost identical over the pH range between 6.7 and 11.6, suggesting that the functional group of amine or boric acid moiety was not included in the CNDs. The effective electrophoretic mobility decreased at an acidic pH of less than 5, and it was suggested that carboxylate moiety was included in the CNDs. A signal of less-charged CNDs was also detected in the electropherogram, and the CNDs were characterized by a CE format of micellar electrokinetic chromatography. Two or four peaks were detected just after the electroosmotic flow; the less-charged CNDs were thus hydrophilic. The affinity interaction was also examined between the major anionic CNDs and a hydrophobic pairing cation. The peak signal of the major anionic CNDs broadened, and its theoretical number of plates decreased in the presence of tetrabutylammonium ion in the separation buffer. A small portion of the anionic CNDs were a little hydrophobic at different degrees, and their effective electrophoretic mobility decreased by the hydrophobic interaction, resulting in peak broadening of the anionic CNDs.

在微波辐射下由谷氨酸或谷氨酸-硼酸混合物合成水溶性碳纳米点（CND）。通过离心过滤进行尺寸分级，将 CND 收集在水溶液中。由此制备的 CND 通过毛细管电泳 (CE) 进行表征。在电泳图中检测到阴离子物质的峰值信号，并且发现它是CND的主要成分。主要成分的有效电泳迁移率在 6.7 至 11.6 之间的 pH 范围内几乎相同，表明 CND 中不包含胺或硼酸部分的官能团。当酸性pH小于5时，有效电泳迁移率降低，表明CND中包含了羧酸根部分。在电泳图中还检测到了带较少电荷的 CND 信号，并且 CND 通过胶束电动色谱的 CE 格式进行了表征。电渗流后立即检测到两个或四个峰值；因此，带较少电荷的 CND 是亲水性的。还检查了主要阴离子 CND 和疏水性配对阳离子之间的亲和相互作用。当分离缓冲液中存在四丁基铵离子时，主要阴离子 CND 的峰信号变宽，其理论板数减少。一小部分阴离子CND具有不同程度的疏水性，其有效电泳迁移率因疏水相互作用而降低，导致阴离子CND的峰变宽。