A specific fluorescence probe for chromium (VI) anions and its application

A facile fluorescent receptor for Cr(VI) anions was designed and prepared by 9-ethyl-9H-carbazole-3,6-dicarbaldehyde and 2-aminobenzenethiol. The interactions of the receptor with various anions were investigated through UV-vis absorption and fluorescence emission spectra, respectively. Experimental results revealed that the receptor could recognize Cr(VI) anions with high selectivity and sensitivity in H2O/DMSO mixed medium. A fluorescence “on-off” signal of the receptor to Cr(VI) anions was observed and verified by 1H NMR and density functional theory (DFT). The detection limit of the receptor for Cr(VI) may be up to 10−7 mol/L. Additionally, the receptor as a fluorescent probe can be used to detect the content of Cr(VI) anions in milks, and displayed good accuracy and sensitivity. The work provides a new strategy for detecting Cr(VI) and developing the application in practical samples and systems.