title: Large volume stacking using an EOF pump in NACE-MS.
abstract: Large volume stacking using an EOF pump (LVSEP) is realized for CE with ESI-MS. In LVSEP of anions, the adverse effects of a long sample matrix plug were overcome by pumping the plug out of the separation capillary to the inlet vial using the EOF under a potential of reverse polarity. Therefore, it was necessary to supply a backup run buffer from the outlet end of the capillary, which was not trivial in most ESI-MS configurations. We solved this difficulty simply by placing a vial supplying a backup run buffer during the matrix removal and sample stacking process. In addition, methanol was used as the run buffer solvent enabling a bare fused-silica capillary to meet the requirement of suppressed EOF. This LVSEP CE/ESI-MS has been successfully applied to six anionic analytes, achieving 400-fold enrichment in the detection sensitivity by using a conventional sheath liquid CE/ESI-MS interface without any physical modification.
authors.affiliation: Department of Chemistry, Seoul National University, Seoul, Korea.
authors.forename: Jihye
authors.initials: J
authors.lastname: Kim
authors.forename: Man-Seog
authors.initials: MS
authors.lastname: Chun
authors.forename: Kihwan
authors.initials: K
authors.lastname: Choi
authors.forename: Doo Soo
authors.initials: DS
authors.lastname: Chung
mesh_terms: D000838:Anions / Q000737:chemistry; D053841:Electroosmosis / Q000295:instrumentation*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D016014:Linear Models; D000432:Methanol / Q000737:chemistry; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods
chemical_list: D000838:Anions; D000432:Methanol