Controlled synthesis of fluorescent carbon materials with the assistance of capillary electrophoresis.

Carbon nanodots (CNDs) have been widely applied in variety of fields, while some evidences indicate their components may be complicated. In this work, capillary electrophoresis (CE) was used to evaluate the effect of synthetic conditions of fluorescent CNDs prepared through the hydrothermal method using citric acid (CA) and Triaminoguanidinium chloride (TG Cl) as the starting materials. The results indicated that the fluorescent components of the products were affected by the ratio of the starting materials, the reaction temperature and reaction time. Under selected conditions, a ratio of TG Cl to CA of 1:6, the reaction at 180 °C for 3 h, the product contains more than 4 fluorescent components with similar optical properties. CNDs were used for the determination of Cr(VI) in environmental samples with recoveries ranging in 95.3–107%, and the mechanism was also confirmed. [Display omitted] • Novel N-doped CNDs were synthesized with hydrothermal method. • The effect of synthetic conditions was evaluated with the capillary electrophoresis. • The reaction conditions affected both the composition and yield of CNDs. • The CNDs contained multiple fluorescent components with similar optical properties. • Sensitive detection of toxic Cr(VI) in environmental samples was achieved. [ABSTRACT FROM AUTHOR]