title: Liquid ultraviolet matrix-assisted laser desorption/ionization -- mass spectrometry for automated proteomic analysis.
abstract: We have combined several key sample preparation steps for the use of a liquid matrix system to provide high analytical sensitivity in automated ultraviolet -- matrix-assisted laser desorption/ionisation -- mass spectrometry (UV-MALDI-MS). This new sample preparation protocol employs a matrix-mixture which is based on the glycerol matrix-mixture described by Sze et al. The low-femtomole sensitivity that is achievable with this new preparation protocol enables proteomic analysis of protein digests comparable to solid-state matrix systems. For automated data acquisition and analysis, the MALDI performance of this liquid matrix surpasses the conventional solid-state MALDI matrices. Besides the inherent general advantages of liquid samples for automated sample preparation and data acquisition the use of the presented liquid matrix significantly reduces the extent of unspecific ion signals in peptide mass fingerprints compared to typically used solid matrices, such as 2,5-dihydroxybenzoic acid (DHB) or alpha-cyano-hydroxycinnamic acid (CHCA). In particular, matrix and low-mass ion signals and ion signals resulting from cation adduct formation are dramatically reduced. Consequently, the confidence level of protein identification by peptide mass mapping of in-solution and in-gel digests is generally higher.
authors.affiliation: Ludwig Institute for Cancer Research, London, UK. r.k.cramer@reading.ac.uk
authors.forename: Rainer
authors.initials: R
authors.lastname: Cramer
authors.forename: Steve
authors.initials: S
authors.lastname: Corless
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry; D010449:Peptide Mapping; D010455:Peptides / Q000032:analysis; D040901:Proteomics; D015203:Reproducibility of Results; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity; D012996:Solutions / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014466:Ultraviolet Rays
chemical_list: D007477:Ions; D010455:Peptides; D029702:Schizosaccharomyces pombe Proteins; D012996:Solutions