MOF-derived DGT for selective monitoring of quinolones and tetracyclines: Tracking antibiotics risks in urban wastewater treatment plant

Environmental challenges of antibiotics contamination have emerged to address severe impacts on ecological stability and human health. Active sampling methods are not well-fitted to study the emerging pollutants since complicated and unstable enrichment devices/chemicals are significantly required for measurements. Diffusive gradients in thin-films (DGT) are proved to be useful for organic compound detection, but limited by its non-specificity for quinolones (QNs) and tetracyclines (TCs) in waters. Consequently, a metal-organic framework derived carbon specific to QNs and TCs was used as binding agent to develop selective DGT (qt-DGT) in this study. qt-DGT had highly selective adsorption capacity for QNs at 85.45–112.59 μg and TCs at 79.19–85.92 μg in a pH range of 4–9 and ionic strength from 0.001 to 0.05 M. Masses of antibiotics accumulated by qt-DGT increased linearly with time in 24 h. After the deployment in a wastewater treatment plant (WWTP) of Beijing, the qt-DGT exhibited stable and selective uptake of QNs and TCs in comparison with traditional HLB-DGT and active sampling methods. With qt-DGT measurements, QNs and TCs up to 1202.3 ng/L from influent forced WWTP became the major sink of antibiotics, and 830.1–966.3 ng/L from effluent warned the inefficient treatment leading to elevated threats on natural waters.