High-entropy metal-organic framework as an efficient fiber coating for headspace solid-phase microextraction of...

Inspired by their abundant coordination-unsaturated metal sites and hierarchical pore structure, high-entropy metal-organic frameworks (HE-MOFs) were fabricated and firstly applied in solid-phase microextraction (SPME), and exhibited outstanding extraction performance for polychlorinated biphenyls (PCBs) pollutants. The morphology and structure of prepared multi-metal-doped HE-UiO-66 was systematically characterized. The HE-UiO-66 was coated on stainless steel wire as SPME fiber for headspace extraction of PCBs followed by gas chromatography-flame ionization detection (GC-FID). Compared to conventional MOFs-coated fiber, HE-UiO-66-coated fiber demonstrated superior stability and extraction efficiency. The discussed adsorption mechanism involves the multiple interaction through Lewis acid-base coordination, π-π stacking interactions, and rich pore architecture. The optimized method achieved a broad linear range, low detection limits, and outstanding enrichment factors (8411-15,377), surpassing previously reported values. Satisfactory recovery rates (77.8-111.9%) were obtained in environmental samples and food samples. This study pioneers the application of HE-MOFs in sample preparation, providing a highly efficient and sensitive method for PCBs detection in complex matrices.