Amino-Functionalized Lanthanide Metal–Organic Frameworks for Ratiometric Detection of Perfluorooctanoic Acid

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant with a global presence in water, air, and soil resources. Herein, a water-stable amine-functionalized lanthanide metal-organic framework (<b>EuTPTC-NH</b>_<b>2</b>) is utilized for ratiometric luminescence detection of PFOA. In the presence of PFOA, there is an increase in the emission intensity of the organic ligand, while the characteristic luminescence intensity of Eu³⁺ ions decreases, accompanied by a distinct emission color change from red to blue. <b>EuTPTC-NH</b>_<b>2</b> exhibits a low limit of detection of 16.1 nM, a rapid response time of 37 s, and an excellent selectivity toward PFOA in distilled water. The experimental and theoretical studies demonstrate the existence of hydrogen bonding, electrostatic interaction, and weak C-F···H-Ar interaction between <b>EuTPTC-NH</b>_<b>2</b> and PFOA. This work offers a novel approach for the highly sensitive and visual detection of per- and polyfluoroalkyl substances in the aqueous phase.