Multicolor nitrogen-doped carbon quantum dots and its application in the detection of Fe³⁺ ion

In this paper, nitrogen-doped carbon quantum dots (N-CQDs) are synthesized by the hydrothermal method. N-CQDs exhibit strong fluorescence, and N-CQDs are well dispersed in water as well as in various organic solvents. N-CQDs emit multi-color fluorescence from blue to red, with wavelengths in the range of 450-650 nm without the need for purification. Furthermore, the fluorescence emission of N-CQDs was selectively quenched after adding Fe³⁺ ions. N-CQDs were used as a nanoprobe for the detection of Fe³⁺ ions, showing a good linear correlation between the fluorescence emission and the concentration of Fe³⁺ in the Fe³⁺ concentration range from 0 to 100 μM. The limit of detection (LOD) was 55.7 μM for Fe³⁺ in water and 40.2 μM in fetal bovine serum (FBS) samples. The study shows that the synthesized N-CQDs have low cost and great potential for application in biological analysis.