title: 3D ToF-SIMS Analysis of Peptide Incorporation into MALDI Matrix Crystals with Sub-micrometer Resolution.
abstract: The analytical sensitivity in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is largely affected by the specific analyte-matrix interaction, in particular by the possible incorporation of the analytes into crystalline MALDI matrices. Here we used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to visualize the incorporation of three peptides with different hydrophobicities, bradykinin, Substance P, and vasopressin, into two classic MALDI matrices, 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (HCCA). For depth profiling, an Ar cluster ion beam was used to gradually sputter through the matrix crystals without causing significant degradation of matrix or biomolecules. A pulsed Bi3 ion cluster beam was used to image the lateral analyte distribution in the center of the sputter crater. Using this dual beam technique, the 3D distribution of the analytes and spatial segregation effects within the matrix crystals were imaged with sub-μm resolution. The technique could in the future enable matrix-enhanced (ME)-ToF-SIMS imaging of peptides in tissue slices at ultra-high resolution. Graphical Abstract ᅟ.
authors.affiliation: Physikalisches Institut, University of Münster, 48149, Münster, Germany. martin.koersgen@uni-muenster.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Körsgen
authors.affiliation: Physikalisches Institut, University of Münster, 48149, Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Pelster
authors.affiliation: Institute for Hygiene, University of Münster, 48149, Münster, Germany.|Interdisciplinary Center for Clinical Research (IZKF), University of Münster, 48149, Münster, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Dreisewerd
authors.affiliation: Physikalisches Institut, University of Münster, 48149, Münster, Germany.
authors.forename: Heinrich F
authors.initials: HF
authors.lastname: Arlinghaus
mesh_terms: D001920:Bradykinin / Q000032:analysis / Q000737:chemistry; D003373:Coumaric Acids / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization; D005841:Gentisates / Q000032:analysis / Q000737:chemistry*; D021621:Imaging, Three-Dimensional; D010455:Peptides / Q000032:analysis / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013373:Substance P / Q000032:analysis / Q000737:chemistry; D014667:Vasopressins / Q000032:analysis / Q000737:chemistry
chemical_list: D003373:Coumaric Acids; D005841:Gentisates; D010455:Peptides; D014667:Vasopressins; C007175:alpha-cyano-4-hydroxycinnamate; D013373:Substance P; D001920:Bradykinin
keywords: Analyte incorporation; Ar cluster ion source; MALDI matrix; ME-SIMS; ToF-SIMS