ZIF-67 Templated Synthesis of Nanoporous Carbon as an Efficient Adsorbent for Preconcentration of Flunitrazepam from Beverage Samples

In this work, a nanoporous carbon (denoted as Co-NC) with high surface area, large pore volumes, strong magnetic response, and good graphitization degree was prepared using zeolitic imidazole framework (ZIF-67) as both a precursor and a template without any additional carbon source. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, vibrating sample magnetometer, and N₂ adsorption were used to characterize the Co-NC. The Co-NC was explored as the magnetic adsorbent, and its adsorption performance was evaluated by extraction of flunitrazepam from beverage samples. Several experimental parameters affecting the extraction efficiencies were investigated and optimized. The results confirmed that the Co-NC showed an excellent adsorption capacity for flunitrazepam.