title: Factors affecting quantitative electrokinetic injections from submicroliter conductive vials in capillary electrophoresis.
abstract: The factors influencing quantitative electrokinetic injections in capillary electrophoresis for custom 340-nL, 10-microL, and 110-microL stainless steel sample vials have been investigated using a six-analyte mixture containing catecholamines and indolamines. Deleterious sample degradation is increased with smaller sampling vials, decreased capillary-electrode distances, and increased current passed during the injection. Zero-voltage injections from the smallest vials also demonstrate additional injection discrepancies when compared to larger-volume bulk solution injections. These effects are in addition to the electrokinetic bias and complicate the selection of appropriate internal standards. For nanoliter-volume conductive vials, the injection process creates new species and eliminates other electroactive species to such an extent that quantitation becomes problematic.
authors.affiliation: Department of Chemistry, University of Illinois, Urbana 61801, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Fuller
authors.forename: J V
authors.initials: JV
authors.lastname: Sweedler
mesh_terms: D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D007700:Kinetics; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods