Metal organic framework/covalent organic framework composite for solid-phase microextraction of polycyclic aromatic hydrocarbons in milk samples

•A novel MOF/COF composite was synthesized by covalently growth of COF on the UiO-66-NH2 surface and physically coated on stainless steel for microextraction.•The MOF/COF composite showed better extraction performance for PAHs compared with its individual material.•It was the first time to use this MOF/COF composite coated stainless steel fiber for HS-SPME.