title: High-efficiency nano- and micro-HPLC--high-resolution Orbitrap-MS platform for top-down proteomics.
abstract: In terms of resolution, mass accuracy, and sensitivity, the Orbitrap represents one of the most potent mass analyzers available today. We here elucidate the potential of interfacing Orbitrap-MS to ion-pair RP HPLC for intact protein analysis. Using gradients of ACN and monolithic columns of 1.0 and 0.10 mm id, peak capacities between 120 and 130 were achievable within 20-25 min separation time. Compared with silica-based stationary phases, protein recovery and carryover from monolithic columns were found clearly superior. Intact proteins were detectable in a mass range covering 5.7-150 kDa with LODs in the low femtomol range. Compared with UV detection, MS detection with a scanning speed of 1.6 s per spectrum on average led to a 26% increase in chromatographic peak widths, whereas chromatographic patterns were mostly preserved in extracted ion chromatograms at an acquisition rate of 0.5 s per spectrum. Isotopic resolution of multiply charged ions was demonstrated for proteins up to 42 kDa. A micro-HPLC-Orbitrap-MS setup employing a 1.0 mm id column was utilized to characterize a 150 kDa recombinant monoclonal antibody. The applicability of nano-HPLC-Orbitrap-MS to the analysis of highly complex protein mixtures is demonstrated for the 70% ethanol extractable subproteome of wheat grains.
authors.affiliation: Department of Molecular Biology, Division of Chemistry and Bioanalytics, University of Salzburg, Salzburg, Austria.
authors.forename: Jens
authors.initials: J
authors.lastname: Mohr
authors.forename: Remco
authors.initials: R
authors.lastname: Swart
authors.forename: Martin
authors.initials: M
authors.lastname: Samonig
authors.forename: Günter
authors.initials: G
authors.lastname: Böhm
authors.forename: Christian G
authors.initials: CG
authors.lastname: Huber
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods; D006801:Humans; D057230:Limit of Detection; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis*; D040901:Proteomics / Q000295:instrumentation / Q000379:methods; D011786:Quality Control; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods
chemical_list: D011506:Proteins