A novel Eu-MOF ratiometric fluorescent probe for visual detection of Hg2+, Cd2+ and formaldehyde

The accumulation of heavy metal ions in nature will not only lead to the further deterioration of the environment, but also directly do harm to human health. And as a gas pollutant, excessive inhalation of formaldehyde is also harmful to human health. Herein, a novel Eu-MOF was synthesized by solvothermal method using Eu3+, 2-pyridine-4-yl-3H-benzimidazole-5-carboxylic acid (HL) and 1,10-phenanthroline (phen), which can be used as a ratio fluorescent probe to detect Hg2+, Cd2+ and formaldehyde, and the limits of detection(LOD) can reach 34, 9.91 and 194 nM respectively. Among them, the LOD of Eu-MOF for Cd2+ has reached the lowest level at present. Noticeable, Eu-MOF can detect formaldehyde in both liquid and gas phases, and the response time is extremely short. In addition, Eu-MOF has been applied to trace detection of Hg2+ and Cd2+ in tap water, lake water and sea water with satisfactory recoveries (ranging from 98.10 % to 103.0 %). A program has been developed for quickly calculating the concentration of the substances to be detected by capturing the fluorescent color of the solvents under the ultraviolet light.