Efficient enrichment and sensitive detection of polychlorinated biphenyls using nanoflower MIL-on-UiO as solid-phase microextraction fiber coating

The sensitive detection of polychlorinated biphenyls (PCBs) is crucial for protecting the environment and human health. Herein, we constructed a Materials Institute Lavoisier 88B (MIL-88B)-on-University of Oslo 66 (UiO-66) composite (MIL-on-UiO) with a unique nanoflower morphology, in which highly stable UiO-66 is the precursor, with MIL-88B grown on its surface. MIL-on-UiO was used as a fiber coating for headspace solid-phase microextraction to enrich PCBs. Experimental results demonstrated that MIL-on-UiO provided better enrichment performance for PCBs than single components due to multiple interactions, including π–π stacking, halogen bonding, pore-filling, and steric hindrance effects. The method established using the MIL-on-UiO-based SPME fiber coating provided a good linear relationship in the range of 0.001–50 ng·mL−1, with limits of detection ranging from 0.0002 to 0.002 ng·mL−1 and enrichment factors between 3530 and 7420. In addition, the method was used to detect trace PCBs in water and orange juice achieving satisfactory recoveries (81%–111%). •A MOF-on-MOF composite (MIL-on-UiO) with nano-flower morphology was constructed•The MIL-on-UiO was utilized as fiber coating of solid-phase microextraction to PCBs•High enrichment factor (3533–7421) to PCBs were achieved with MIL-on-UiO as coating•A HS-SPME coupling with GC-FID strategy for detecting PCBs has been developed