In situ conversion of waste PET into a Cu-MOF-derived coating on a copper wire surface for solid-phase...

This study developed a green and low-cost fabrication strategy for solid-phase microextraction (SPME) fibers. Using waste polyethylene terephthalate (PET) as the sole organic ligand source, a Cu-based metal-organic framework (Cu-MOF) coating was in situ grown on a copper wire substrate via a one-step hydrothermal method. Subsequently, the coating was in situ transformed into a Cu-MOF-derived carbon-based coating (Cu-MOFs-C) through pyrolysis under a nitrogen atmosphere. Characterization results indicated that the resultant coating featured a loose three-dimensional network structure. The fiber was applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples via solid-phase microextraction-high-performance liquid chromatography (SPME-HPLC). Under optimized conditions, the method exhibited excellent linearity within the range of 0.05-200 µg L^-1 (R > 0.998) and low limits of detection (LODs) ranging from 0.010 to 0.061 µg L^-1. Spiked recoveries in real water samples (river and lake water) ranged from 84.7% to 110.8%. Furthermore, the fiber demonstrated outstanding reusability, retaining recoveries of 87.7-91.48% even after 100 extraction cycles. Compared with previously reported methods, this approach offers superior LODs, recovery rates, and environmental friendliness. This work provides a novel strategy for the high-value utilization of waste PET and the sensitive monitoring of PAHs in aquatic environments.