title: Comparison of surfactants for dynamic surface modification of poly(dimethylsiloxane) microchips.
abstract: In the present report, the use of negatively charged surfactants as modifiers of the background electrolyte is reported using poly(dimethylsiloxane) (PDMS) microchips. In particular, the use of anionic surfactants, such as sodium dodecyl sulfate, phosphatidic acid, and deoxycholate, was studied. When surfactants were present in the run buffer, an increase in the electroosmotic flow (EOF) was observed. Two additional effects were also observed: (i) stabilization of the run-to-run EOF, (ii) an improvement in the electrochemical response for several biomolecules. In order to characterize the analysis conditions, the effects of different surfactant, electrolyte, and pH were studied. EOF measurements were performed using either the current monitoring method or by detection of a neutral molecule. The first adsorption/desorption kinetics studies are also reported for different surfactants onto PDMS. The separation of biologically important analytes (glucose, penicillin, phenol, and homovanillic acid) was improved decreasing the analysis time from 200 to 125 s. However, no significant changes in the number of theoretical plates were observed.
authors.affiliation: Chemistry Department, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Carlos D
authors.initials: CD
authors.lastname: García
authors.forename: Brian M
authors.initials: BM
authors.lastname: Dressen
authors.forename: Amber
authors.initials: A
authors.lastname: Henderson
authors.forename: Charles S
authors.initials: CS
authors.lastname: Henry
mesh_terms: D000327:Adsorption; D003840:Deoxycholic Acid / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000379:methods; D007700:Kinetics; D046208:Microchip Analytical Procedures / Q000379:methods*; D008904:Miniaturization; D009995:Osmosis; D010712:Phosphatidic Acids / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013499:Surface Properties / Q000187:drug effects; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D004129:Dimethylpolysiloxanes; D010712:Phosphatidic Acids; D012828:Silicones; D013501:Surface-Active Agents; D003840:Deoxycholic Acid; D012967:Sodium Dodecyl Sulfate; C013830:baysilon