Preparation of Eu3+-Doped Ca0.8Yb0.2F2.2 as a Fluorescent Probe and Its Application in Detecting Cr O 4 2− and C r 2 O 7 2− Ions

The accurate detection of hexavalent chromium (Cr(VI)) is crucial for environmental protection and public health. Rare earth fluorides have attracted considerable attention as fluorescent sensing materials due to their distinctive properties, including low lattice phonon energy, exceptional chemical stability and long fluorescence lifetime. This study reports the successful one-step hydrothermal synthesis of a Eu3+-doped Ca0.8Yb0.2F2.2 fluorescent probe with excellent aqueous dispersibility. The obtained probe showed high sensitivity towards CrO 4 2− and Cr 2 O 7 2− ions, achieving detection limits of 1.45 µM and 1.50 µM. The obtained probe exhibited remarkable stability across a wide pH range (3 - 11) and strong anti-interference capability, confirming its suitability for analyzing real water samples. Owing to its robust performance and straightforward operation, this fluorescent probe presents a promising approach for efficient monitoring of trace Cr(VI) contaminants in aqueous environments.