Sensitive and selective chemosensor for Fe3+detection using carbon dots synthesized by microwave method

The excessive accumulation of heavy metal ions can pose significant hazards to human health and the environment, hence the detection and removal of heavy metal ions from water bodies are essential. Generally, carbon dots (CDs) are used as a good fluorescence sensor to sense heavy metal ions. In this study, using one-step microwave method, CDs were synthesized with the traditional Chinese medicine Radix Vladimiriae as a carbon source for the first time. These CDs display excellent fluorescence properties with an average particle size of approximately 5.9 nm and a fluorescence quantum yield (QY) about 0.15. The fluorescence emission spectra were recorded at different excitation peaks with the highest intensity emission peak observed at 465 nm with an excitation wavelength of 360 nm. Interestingly, fluorescence intensities of CDs greatly decreased in the existence of Fe3+. Under optimum conditions, a good linear relationship was observed between (I0-I)/I and the Fe3+ concentration in the range of 0.2-200 mu M with the correlation coefficient (R2) of 0.9992 and the limit of detection (LOD) of 62 nM. Finally, after adding Fe3+ at concentrations of 5 mu M, 20 mu M, and 50 mu M to real water samples, the relative standard deviation and spiked recovery rates were 1.2 %-2.7 % and 99.2 %-101.6 %, respectively. Thus, a novel method for rapid detection of Fe3+ were successfully discovered.