Highly sensitive fluorescent probe for Cr~(3+) detection using carbon quantum dots

摘要

Carbon quantum dots (CQDs) had been widely applied in the metal ions detection area due to their excellent optical properties and low toxicity. Herein, a series of CQDs with different sizes were prepared by a facile but effective hydrogen peroxide (H_2O_2) oxidative method using activated carbon as carbon source. Experimental results showed that the concentration of H_2O_2 aqueous solution had critical effect on the sizes and surface structure of CQDs. When H_2O_2 aqueous solution was 20 wt.%, the diameter of CQDs was 3.6 nm, and the fluorescent probe exhibited a good linear response to Cr~(3+) in the concentration range from 0.2 to 55 μM with a detection limit of 0.2 μM. Through systematically analyzing FTIR, XPS and the optical properties of CQDs, the high sensitivity of CQDs for detecting Cr~(3+) was attributed to the synergistic effect of the surface oxygen-containing functional groups and size of CQDs.