title: Critical factors for high-performance physically adsorbed (dynamic) polymeric wall coatings for capillary electrophoresis of DNA.
abstract: Physically adsorbed (dynamic) polymeric wall coatings for microchannel electrophoresis have distinct advantages over covalently linked coatings. In order to determine the critical factors that control the formation of dynamic wall coatings, we have created a set of model polymers and copolymers based on N,N-dimethylacrylamide (DMA) and N,N-diethylacrylamide (DEA), and studied their adsorption behavior from aqueous solution as well as their performance for microchannel electrophoresis of DNA. This study is revealing in terms of the polymer properties that help create an "ideal" wall coating. Our measurements indicate that the chemical nature of the coating polymer strongly impacts its electroosmotic flow (EOF) suppression capabilities. Additionally, we find that a critical polymer chain length is required for polymers of this type to perform effectively as microchannel wall coatings. The effective mobilities of double-stranded (dsDNA) fragments within dynamically coated capillaries were determined in order to correlate polymer hydrophobicity with separation performance. Even for dsDNA, which is not expected to be a strongly adsorbing analyte, wall coating hydrophobicity has a deleterious influence on separation performance.
authors.affiliation: Department of Chemical Engineering, Northwestern University, 2145 Sheridan Road, Room E136, Evanston, IL 60208, USA.
authors.forename: Erin A S
authors.initials: EA
authors.lastname: Doherty
authors.forename: K Derek
authors.initials: KD
authors.lastname: Berglund
authors.forename: Brett A
authors.initials: BA
authors.lastname: Buchholz
authors.forename: Igor V
authors.initials: IV
authors.lastname: Kourkine
authors.forename: Todd M
authors.initials: TM
authors.lastname: Przybycien
authors.forename: Robert D
authors.initials: RD
authors.lastname: Tilton
authors.forename: Annelise E
authors.initials: AE
authors.lastname: Barron
mesh_terms: D000178:Acrylamides; D000327:Adsorption; D004247:DNA / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D011108:Polymers / Q000737:chemistry*; D012212:Rheology
chemical_list: D000178:Acrylamides; D011108:Polymers; C428028:poly(N,N-diethylacrylamide); D004247:DNA; C099046:N,N-dimethylacrylamide