title: Fraction collection in capillary electrophoresis for various stand-alone mass spectrometers.
abstract: A procedure for collecting fractions during capillary electrophoresis for their analysis using various stand-alone instruments is described. The results of a systematic study of the optimization and application of capillary electrophoresis (CE) in conjunction with a reverse-phase high-performance liquid chromatography electrospray ionization quadrupole time of flight-tandem mass spectrometry (RP-HPLC-ESI-Q-TOF-MS/MS) and inductively-coupled mass spectrometry (ICP-MS) to the analysis of the seed extract of the Japanese Pagoda Tree (Sophora japonica) are presented. The off-line coupling of CE to the matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the proteins mixture was applied. The cathode end of the capillary was placed inside a stainless steel needle using a coaxial liquid-sheath-flow configuration. The optimization of experimental parameters resulted in an efficient methodology for MS analysis of fractions. Several components contained in the extract of S. japonica were identified, some not previously known. It was demonstrated that low sensitivity, which is a real problem in off-line CE-MS analysis, could be tolerated because of a more flexible optimization of the CE separation conditions and the choice of independent stand-alone instruments for analysis of separated fractions. The estimated limit of detection for CE-RP-HPLC-ESI-Q-TOF-MS was 50 microM of polyphenols and for CE-ICP-MS, 1-100 microg/l.
authors.affiliation: Department of Chemistry, Faculty of Science, Tallinn University of Technology, Tallinn, Estonia.
authors.forename: Kati
authors.initials: K
authors.lastname: Helmja
authors.forename: Maria
authors.initials: M
authors.lastname: Borissova
authors.forename: Tatjana
authors.initials: T
authors.lastname: Knjazeva
authors.forename: Martin
authors.initials: M
authors.lastname: Jaanus
authors.forename: Urmas
authors.initials: U
authors.lastname: Muinasmaa
authors.forename: Mihkel
authors.initials: M
authors.lastname: Kaljurand
authors.forename: Merike
authors.initials: M
authors.lastname: Vaher
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation; D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D013058:Mass Spectrometry / Q000295:instrumentation*; D010936:Plant Extracts / Q000032:analysis*; D011506:Proteins / Q000032:analysis; D012015:Reference Standards; D012639:Seeds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D029909:Sophora / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation
chemical_list: D010936:Plant Extracts; D011506:Proteins