title: On-column sample preconcentration using sample matrix switching and field amplification for increased sensitivity of capillary electrophoretic analysis of physiological samples.
abstract: An on-line sample concentration method using sample matrix switching and field amplification peak stacking has been developed. A microbore LC guard column is used to slightly retain the analytes in order to switch from a high ionic strength sample matrix (the physiological fluid) to a low ionic strength matrix (the LC mobile phase). The eluted LC peak is then trapped in a CE system and preconcentrated by field amplification peak stacking. The concentrated sample peak is then analyzed by CE. Compared to normal hydrodynamic injection, the sensitivity was increased by more than 500-fold without loss in resolution. A limit of detection of less than 10 nM for a physiological sample was achieved using UV adsorption detection. This method can be used for negatively or positively charged analytes.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence 66045, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: K
authors.initials: K
authors.lastname: McLaughlin
authors.forename: C E
authors.initials: CE
authors.lastname: Lunte
mesh_terms: D002045:Bupivacaine / Q000032:analysis*; D004574:Electromagnetic Fields; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D017551:Microdialysis; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002045:Bupivacaine