Development of a syringe membrane-based microextraction method based on metal–organic framework mixed-matrix membranes for preconcentration/extraction of polycyclic aromatic hydrocarbons in tea infusion

Inevitably, the residues of polycyclic aromatic hydrocarbons (PAHs) in tea leaves will be transferred to hot tea infusion, constituting a certain drinking risk; consequently, it is imperative to develop rapid, sensitive, and robust approaches for their trace-level detection. Herein, we developed a syringe membrane-based microextraction (SMME) method for preconcentration/extraction of PAHs in tea infusions. This method utilized metal–organic framework-mixed matrix membranes (MOF-MMMs) as adsorbents, which anchored the nanoparticles of MOFs onto the surface of PVDF membrane. The UiO-66 (Zr)-based MMM possessed high Brunauer-Emmett-Teller (BET) surface area (320.5 m 2 g −1 ) and pore volume (0.18 cm 3 g −1 ), thus enhancing extraction/adsorption efficiency. Under optimized conditions, the limits of detection for PAHs reached as low as 0.02–0.08 μg L −1 with extraction recoveries of 85.5–102.1%, and the inter-day and intra-day precision was lower than 8.4% in tea infusions. Consequently, the SMME/HPLC-DAD method shows a great potential in conventional monitoring of PAHs in tea samples.