Selective Separation and Quantification of Tetracycline Antibiotics Using Ionic Liquid-Functionalized MOF-Derived Diffusive Gradients in Thin Films

A selective phase for tetracycline antibiotics (TAs) uptake was designed by incorporating [BMIM][PF 6 ]-functionalized ZIF-67-derived carbonaceous material into the diffusive gradients in a thin-films (DGT) device. This material, integrated in the binding gel of DGT (ta-DGT), exhibited specifically strong affinity toward tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), with adsorption capacities of 12.22, 11.81, and 13.78 µg/disc, respectively. The ta-DGT showed preferential uptake of TAs over coexisting antibiotics and organic contaminants, with adsorption ratios above 80% and stable performance over pH 4–9 and ionic strength of 0.001–0.1 M. Mechanistic analysis indicated that π–π electron donor–acceptor interactions and cation–π bonding facilitated the specific targeting of TAs onto ta-DGT. During 7 days of field deployment in a domestic wastewater treatment plant in Beijing, ta-DGT showed 5–40 times higher detectable concentrations than conventional HLB/XAD DGT devices. These results validated its sensitivity, reliability, and feasibility for the selective separation and quantification of TAs in complex aqueous matrices.