HIGH-EFFICIENCY CROSS-LINKED POLYACRYLAMIDE COATING FOR CAPILLARY ELECTROPHORESIS OF PROTEINS

A highly efficient cross-linked polyacrylamide capillary coating has been developed for capillary electrophoresis of proteins. The fused silica capillary tubing was pretreated with 7-oct-1-enyltrimethoxysilane and then statically coated with the polymerization reagents. The copolymerization re-action was performed at 120-degrees-C when using a free-radical initiator. Coated columns were evaluated for the separation of both basic and acidic proteins. Methylene bisacrylamide was added in the preparation of the cross-linked polyacrylamide coating, and the cross-linking effects on column performance were evaluated. Both linear and cross-linked columns gave high separation efficiencies and good reproducibilities for proteins, and electroosmotic flow was eliminated. It was found that the cross-linked polyacrylamide coatings produced nearly double the efficiencies and only one third the relative standard deviations in migration times for proteins when compared to linear polyacrylamide coatings. Highly efficient and reproducible separations of proteins in human serum samples were achieved using the cross-linked column.