Preparation and application of DES doped carbon quantum dots for fluorescent chromium ions determination

This paper uses orange peel and deep eutectic solvents as precursors to prepare DES-CQDs via one-step hydrothermal method. The average size of DES-CQDs is 5.5 nm, with abundant luminescent groups such as amino and hydroxyl groups on the surface. Under the excitation of ultraviolet light at 360 nm, blue fluorescence with a wavelength of 452 nm is emitted. In addition, to investigate the practical application effect of DES-CQDs, this study further used DES-CQDs as fluorescent sensor to detect Cr6+ ions in solutions. The results showed that Cr6+ exhibited a significant quenching effect on DES-CQDs, consistent with the quenching mechanism of static quenching and internal filtering effect, and the limit of detection was 3.2 nM. The recovery rates of Cr6+ spiked in four environmental samples are 94.27 ~ 100.51%, indicating that DES-CQDs can be used for the detection of Cr6+ in complex environmental samples.