title: Separation of peptides and proteins by capillary electrophoresis using acidic buffers containing tetraalkylammonium cations and cyclodextrins.
abstract: A method for improving separations of peptides and other positively charged species in capillary zone electrophoresis with untreated capillaries using acidic buffers containing tetraalkylammonium cations is described. Tetramethylammonium and tetrabutylammonium cations dynamically modify the capillary surface, leading to a reversal in the direction of the electroosmotic flow. As a result, the adsorption of positively charged peptides and proteins is minimized, and resolution and peak capacity are improved as the migration of cationic analytes is counterbalanced by the electroosmotic flow. The combining effect of reversing electroosmotic flow and cyclodextrin inclusion complexation on separations of closely related peptides and a protein mixture, as well as tryptic digest of hemoglobin is demonstrated.
authors.affiliation: Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Changyu
authors.initials: C
authors.lastname: Quang
authors.forename: Amir
authors.initials: A
authors.lastname: Malek
authors.forename: Morteza G
authors.initials: MG
authors.lastname: Khaledi
mesh_terms: D002021:Buffers; D002412:Cations; D003505:Cyclodextrins / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010455:Peptides / Q000032:analysis* / Q000737:chemistry; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013501:Surface-Active Agents; D013997:Time Factors; D014357:Trypsin
chemical_list: D002021:Buffers; D002412:Cations; D003505:Cyclodextrins; D006454:Hemoglobins; D010455:Peptides; D011506:Proteins; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C009405:tetrabutylammonium; D014357:Trypsin; C027917:tetramethylammonium