Facile one-step synthesis of highly luminescent N-doped carbon dots as an efficient fluorescent probe for chromium() detection based on the inner filter effect

Chromium is highly toxic and considered as a severe contaminate. Therefore, low cost, highly sensitive sensors for the determination of Cr( vi ) are highly required. In the present study, highly luminescent N-doped carbon dots (CG-CDs) obtained from citric acid and glycine with a quantum yield of 78% and label-free fluorescent assay system were designed for Cr( vi ) detection based on the inner filter effect (IFE). The CG-CDs were prepared by a one-step hydrothermal method using citric acid and glycine as carbon precursors. The fluorescent sensors showed rapid response, high selectivity, and sensitivity to Cr( vi ). A good linear relationship between the concentration of Cr( vi ) ions and fluorescence intensity was obtained in the range from 5 to 200 μmol L −1 ( R 2 = 0.98), and the limit of detection was calculated to be 4.16 μmol L −1 for Cr( vi ). Importantly, this method has been successfully applied to the detection of Cr( vi ) ions in simulated aquaculture water, which may be helpful to reduce the risk of Cr( vi ) intake from contaminated water. Label-free fluorescence assay system is designed for Cr( iv ) detection.