“…Recently, composite materials such as TiO 2 -ceramics nanobers, 11 polymeric ionic liquids-graphene, 5 polypyrrolegraphene, 12 MOF hybridized with other compounds, [13][14][15][16] have been applied as the ber coatings, which simultaneously combine the inherent and special characteristics of different materials. To achieve the stable immobilization of coating materials on the substrate, versatile methods have been introduced, including chemical vapor deposition, 17 electrospun, 11 sol-gel technique, 18,19 in situ polymerization, 20 in situ oxidation of metal wires, 21 electroless plating, 22 layer-to-layer assemble. 23 Nowadays, the application of SPME has been mainly focused on the extraction of nonpolar compounds, leaving much room for exploration of novel polar coating materials and immobilization methods.…”