title: Off-line coupling of capillary electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
abstract: An automated fraction collection interface is used in conjunction with matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry to analyze material isolated by capillary electrophoresis (CE). CE fractions are deposited directly on the MALDI probes so that individual peaks from the electropherogram are associated with a single sample spot on the probe. MALDI matrices with high acid concentrations afford enhanced tolerance of electrophoresis buffers. The utility of this hybrid instrument is demonstrated by separation and mass analysis of a tryptic digest of cytochrome c and synthetic mixtures of four proteins. Mass assignments corresponding to the protonated molecular ions are in good agreement with those predicted from molecular structure. Miniaturization of the interface affords enhanced sensitivity, with good-quality spectra from separations of as little as 25 fmol of protein.
authors.affiliation: Department of Chemistry, University of California, Riverside 92521-0403, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Walker
authors.forename: R W
authors.initials: RW
authors.lastname: Chiu
authors.forename: C A
authors.initials: CA
authors.lastname: Monnig
authors.forename: C L
authors.initials: CL
authors.lastname: Wilkins
mesh_terms: D000595:Amino Acid Sequence; D019075:Electrophoresis, Capillary / Q000379:methods*; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis* / Q000302:isolation & purification; D011506:Proteins / Q000032:analysis* / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides; D011506:Proteins