LAUSR

Abstract Covalently linked capillary coating of sodium polystyrene sulfonate (PSS) is prepared using the layer by layer self-assembly technique combined with photochemistry reactions. PSS coating based on ionic bonding was first assembled on the inner wall of capillary by using photosensitive diazoresin (DR) as the coupling agent, and then the ionic bonding was converted into covalent bonding after treatment with UV light through a unique photochemistry reaction of DR. DR/PSS covalent coating resisted protein adsorption on the inner surface of the capillary, and thus a baseline separation of various proteins (Lys, Cyt-c, BSA and RNase A) was achieved in a short time by capillary electrophoresis (CE). Compared with bare capillary and uncrosslinked DR/PSS coating, the covalent coating has good stability and reproducibility. Because of the replacement of highly toxic and moisture-sensitive silane coupling agent by DR in the covalent coating preparation, this method may provide a green and easy way to make the covalently coated capillaries for CE.