A novel sandwich method to prepare robust SPME polymer coating on glass slide with controllable thickness for direct analysis through fluorescence and MS imaging

Abstract For a range of analytical applications, the microchips and slides used in sample preparation should be coated with functional (polymeric) materials. These coatings need to have controlled thickness, appropriate chemical/physical properties such as strong adhesion, and strength to resist external forces. Herein, we address these challenges using simple strategy to prepare polymer coatings by sandwiching a porous membrane soaked in vinyl monomer mixture between two glass slides, a bare slide and a slide immobilized with 3-(methacryloyloxy) propyltrimethoxysilane, and then thermal co-polymerization of monomers in the membrane and on the slide. The composite polymer coatings of different thickness (43∼227 μm) were formed on the slides by adjusting the thickness of support membrane (polytetrafluoroethylene). The composite polymer coated slides were successfully used for usual solid-phase microextraction, and for the visual detection of dyes and for fluorescent imaging and direct-to-MS detection without elution. The coatings have excellent stability, stiffness, and can be reused. They might be used in a variety of diagnostic and proteomics applications.