Abstract

In capillary electrophoresis, a common approach to prevent adsorption of an analyte onto a capillary's inner surface is to use surfactants as coating materials. These coating materials form a bilayer structure that resembles the arrangement of phospholipids (natural surfactants) in cell membranes. In this study, a bilayer coating was produced on the surface of a capillary using either a double-chained cationic surfactant, dimethyldioctadecylammonium bromide (2C(18)DAB), or a triple-chained cationic surfactant, tridodecylmethylammonium iodide (3C(12)MAI). The resulting bilayer coatings were investigated in the presence of various neutral cyclodextrins using hydrodynamic rinsing and performing successive runs. All types of cyclodextrins that were investigated had the effect of partially destabilizing the bilayer. However, cyclodextrin, as well as type of surfactant has a remarkable effect on the extent of a bilayer's stability. The most stable bilayer was obtained on capillaries coated with 2C18DAB using HP-bCD as the running buffer. Under such conditions, reversed EOF (electroosmotic flow) decreased only by 1.5 in over 100 min of electrophoretic separation.