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][PF6]-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.