Preparation of biomass water‐soluble carbon quantum dots and their application in Cr (VI) ions detection

Abstract

To quickly and quantitatively detect the concentration of harmful Cr 6+ in food and packaging, biomass nitrogen-doped blue fluorescent carbon quantum dots (CQDs) were synthesized by a one-step hydrothermal method using longan peel. The synthesized biomass CQDs are spherical, and the particle size is distributed between 1 and 6 nm. There are functional groups such as carboxyl, hydroxyl and amino groups on the surface of the CQDs, which promotes the excellent water dispersibility of the CQDs. CQDs have good fluorescence stability in salt solutions, different pH environments and long-term storage. A fluorescence sensor for detecting Cr 6+ was constructed, based on the specific quenching effect of Cr 6+ on the fluorescence of CQDs. There is a good linear relationship between the fluorescence quenching rate of the fluorescence sensor and the Cr 6+ concentration of the detected sample. The sensor has a linear range of 20-200 μM and a detection limit of 1.4 μM. In addition, the CQDs fluorescence sensor has an ideal recovery rate in the actual water sample spiked with Cr 6+ . This research innovatively combined longan and hydrothermal method to prepare a quantitative, fast and wide detection limit Cr 6+ sensor.

In situ synthesis of S‐doped coal‐based carbon quantum dots and its application to Cr6+ detection

“…He et al developed a CQDs fluorescence sensor with a linear range of 20–200 μmol. The detection limit of Cr 6+ was 1.4 μmol 45 . By doping atoms, CQDS can effectively improve its performance in analytical sensing, be more sensitive in ion detection, and effectively reduce the detection limit 46 .…”

“…The detection limit of Cr 6+ was 1.4 μmol. 45 By doping atoms, CQDS can effectively improve its performance in analytical sensing, be more sensitive in ion detection, and effectively reduce the detection limit. 46 The detection limit in this study is lower than that in some reports.…”