title: Advancing matrix-assisted laser desorption/ionization-mass spectrometric imaging for capillary electrophoresis analysis of peptides.
abstract: In this work, the utilization of matrix-assisted laser desorption/ionization-mass spectrometric imaging (MALDI-MSI) for capillary electrophoresis (CE) analysis of peptides based on a simple and robust off-line interface has been investigated. The interface involves sliding the CE capillary distal end within a machined groove on a MALDI sample plate, which is precoated with a thin layer of matrix for continuous sample deposition. MALDI-MSI by time of flight (TOF)/TOF along the CE track enables high-resolution and high-sensitivity detection of peptides, allowing the reconstruction of a CE electropherogram while providing accurate mass measurements and structural identification of molecules. Neuropeptide standards and their H/D isotopic formaldehyde-labeled derivatives were analyzed using this new platform. Normalized intensity ratios of individual ions extracted from the CE trace were compared to MALDI-MS direct analysis and the theoretical ratios. The CE-MALDI-MSI results show potential for sensitive and quantitative analysis of peptide mixtures spanning a wide dynamic range.
authors.affiliation: School of Pharmacy, University of Wisconsin-Madison, 53705, United States.
authors.forename: Junhua
authors.initials: J
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Ye
authors.forename: Zichuan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Xiang
authors.forename: Gary
authors.initials: G
authors.lastname: Girdaukas
authors.forename: Lingjun
authors.initials: L
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D019075:Electrophoresis, Capillary / Q000379:methods*; D005557:Formaldehyde / Q000737:chemistry; D007553:Isotope Labeling; D057054:Molecular Imaging / Q000379:methods*; D010455:Peptides / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides; D005557:Formaldehyde