title: Metal cation control of electroosmotic flow magnitude in phospholipid-coated capillaries.
abstract: CZE has become widespread for the separation and analysis of biomolecules such as proteins and peptides, due to factors such as, the speed of the separations, low sample volume, and high resolution associated with the technique. However, the separation of biomolecules by CZE does present a significant challenge due to the electrostatic attraction and adsorption of cationic, or cation containing, biomolecules to the capillary surface. To that end numerous methods have been developed to passivate, or protect the surface, in order to prevent the adsorption of analytes. Yet, in the process of protecting the capillary surface, the potential for further modification of the EOF, a factor crucial to effective analyte resolution, is greatly diminished. In seeking to overcome this limitation we have explored the potential of incorporating a range of metal cations into a phospholipid bilayer capillary coating. It has previously been established that the inclusion of calcium into the separation buffer with a phospholipid coating will reverse the EOF in the capillary. Here, we present our investigation of a broader range of metal cations included in the separation buffer (Ca(2+) , Mg(2+) , Co(2+) , Ni(2+) , Sr(2+) , Ba(2+) , and Ce(3+) ) revealing that the choice of metal cation can drastically influence the EOF, with observed values between -3.80 × 10(-4) and -5.74 × 10(-5) cm(2) /V·s.
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA.
authors.forename: Shane S
authors.initials: SS
authors.lastname: Wells
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA.
authors.forename: Eduardo
authors.initials: E
authors.lastname: De La Toba
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Harrison
mesh_terms: D000327:Adsorption; D002412:Cations / Q000737:chemistry; D053841:Electroosmosis; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D008051:Lipid Bilayers; D008670:Metals / Q000737:chemistry; D009211:Myoglobin / Q000032:analysis; D010743:Phospholipids / Q000737:chemistry*; D012260:Ribonucleases / Q000032:analysis; D055672:Static Electricity
chemical_list: D002412:Cations; D008051:Lipid Bilayers; D008670:Metals; D009211:Myoglobin; D010743:Phospholipids; D012260:Ribonucleases
keywords: Electroosmotic flow; Electroosmotic flow control; Phospholipid bilayer; Protein