title: Off-line coupling of high-resolution capillary electrophoresis to MALDI-TOF and TOF/TOF MS.
abstract: High-resolution capillary electrophoresis has been coupled to MALDI-TOF and TOF/TOF MS through off-line vacuum deposition onto standard stainless steel MALDI targets. This off-line approach allowed the decoupling of the separation from the MS analysis, thus allowing each to be independently optimized in terms of time. Using BSA tryptic digest as a model sample, the deposited streaks, roughly 100-microm wide, were first analyzed in the MS mode, consuming only a fraction of the sample. After data analysis, segments of the deposited trace, containing unidentified peptides, as well as several species chosen for sequence confirmation, were reanalyzed in the MS/MS mode using MALDI-TOF/TOF MS. Additionally, it is shown that the shot-to-shot reproducibility of the vacuum-deposited trace (5% RSD) is 1 order of magnitude lower than that found for the standard dried droplet method. Moreover, a linear dependence of signal intensities (relative to an internal standard) over 3 orders of magnitude was found for a peptide sample with concentrations ranging from 1 to 1000 nM. This paper demonstrates the potential of off-line coupling of high-resolution separations to MALDI-MS and MALDI-MS/MS using vacuum deposition for the analysis of complex peptide mixtures from protein digests.
authors.affiliation: Barnett Institute and Department of Chemistry, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Tomas
authors.initials: T
authors.lastname: Rejtar
authors.forename: Ping
authors.initials: P
authors.lastname: Hu
authors.forename: Peter
authors.initials: P
authors.lastname: Juhasz
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Campbell
authors.forename: Marvin L
authors.initials: ML
authors.lastname: Vestal
authors.forename: Jan
authors.initials: J
authors.lastname: Preisler
authors.forename: Barry L
authors.initials: BL
authors.lastname: Karger
mesh_terms: D019075:Electrophoresis, Capillary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization