title: Suppression of electroosmotic flow and prevention of wall adsorption in capillary zone electrophoresis using zwitterionic surfactants.
abstract: Addition of zwitterionic surfactants such as dodecyldimethyl(3-sulfopropyl)ammonium hydroxide, hexadecyldimethyl(3-sulfopropyl)ammonium hydroxide, and coco (amidopropyl)hydroxyldimethylsulfobetaine (Rewoteric AM CAS U) to an electrophoretic buffer suppress the electroosmotic flow by 50-90%. Onset of suppression occurs at approximately the critical micelle concentration of the surfactant. CAS U effectively suppresses the electroosmotic flow over the pH range 3-12. Addition of 2 mM CAS U to the electrophoretic buffer prevents adsorption of cationic proteins lysozyme, α-chymotrypsinogen A, cytochrome c, and ribonuclease A. Migration time reproducibility for these proteins is ∼1% RSD within 1 day and 2-5% from day to day. Efficiencies in excess of 750 000 plates/m and recoveries of >80% were observed for protein injections from distilled water. Alternatively if 2 mM CAS U is added to samples, recoveries were quantitative, although efficiencies decreased to 325 000-600 000 plates/m. The natural electroosmotic flow of the capillaries is regenerated simply by rinsing with sodium hydroxide.
authors.affiliation: Department of Chemistry, The University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4.
authors.forename: K K
authors.initials: KK
authors.lastname: Yeung
authors.forename: C A
authors.initials: CA
authors.lastname: Lucy