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    Abstract The separation of trace impurities in cimetidine drug substance by high pressure liquid chromatography (HPLC) showed a series of minor components. These were analysed using an on‐line electrospray source connected to a Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometer. Working typically with a resolution of 10 000–20 000 accurate mass measurement of the components confirmed their empirical formulae to generally better than 5 ppm accuracy. This work shows that the combination of conventional analytical HPLC using 4.6 mm columns with a low flow rate electrospray source interfaced to an FT‐ICR mass spectrometer enables structural information to be obtained on low levels of low mass components.
    Ion cyclotron resonance
    Extractive electrospray ionization
    Selected ion monitoring
    Citations (18)
    The potential of electrospray ionization (ESI) Fourier transform ion cyclotron mass spectrometry (FTICR-MS) to assist in the structural characterization of monomeric and dimeric derivatives of the macrophage colony stimulating factor beta (rhM-CSF beta) was assessed. Mass spectrometric analysis of the 49 kDa protein required the use of sustained off-resonance irradiation (SORI) in-trap cleanup to reduce adduction. High resolution mass spectra were acquired for a fully reduced and a fully S-cyanylated monomeric derivative (approximately 25 kDa). Mass accuracy for monomeric derivatives was better than 5 ppm, after applying a new calibration method (i.e., DeCAL) which eliminates space charge effects upon high accuracy mass measurements. This high mass accuracy allowed the direct determination of the exact number of incorporated cyanyl groups. Collisionally induced dissociation using SORI yielded b- and y-fragment ions within the N- and C-terminal regions for the monomeric derivatives, but obtaining information on other regions required proteolytic digestion, or potentially the use of alternative dissociation methods.
    Ion cyclotron resonance
    Top-down proteomics
    The coupling of Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with electrospray ionization has advanced the analysis of large biopolymers and provided the basis for high-throughput protein characterization (e.g., for rapid "proteome" analyses). In this work, the combination of high-performance capillary liquid chromatography with FTICR mass spectrometry and external ion accumulation has been shown to increase both sensitivity and analysis duty cycle. Instrument versatility is further improved by ion preselection followed by ion accumulation in an external linear quadrupole ion trap. The interface was tested with a 3.5-T FTICR mass spectrometer and evaluated with a number of peptides and proteins whose molecular weights ranged from 500 to 66 000. A significant increase in the sensitivity, duty cycle, and dynamic range over that of the previously used accumulated trapping was achieved, exhibiting a detection limit of ∼10 zmol (∼6000 molecules) for smaller proteins such as cytochrome c. Capillary LC external accumulation interface with FTICR was successfully applied for the study of whole-proteome mouse tryptic digests.
    Top-down proteomics
    Ion cyclotron resonance
    Selected ion monitoring
    Quadrupole ion trap
    Hybrid mass spectrometer
    Citations (76)
    Electrospray ionization (ESI) can transfer large biopolymers and many noncovalently bound complexes into the gas phase and to preserve specific noncovalent biomolecular associations for subsequent mass spectrometric analysis. Although a number of details of the ESI process remain a subject of debate, it is now incontestable that many weak associations can survive transfer to the gas phase and are stable for periods of at least seconds. In this presentation, the application of ESI-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry methods for the study of large biopolymers and their noncovalent complexes will be described. It will also be shown that competitive binding studies can be used to quickly establish relative binding affinities in solution, allowing combinatorial libraries to be rapidly screened. After measurements of the intact complex, dissociation studies can be conducted to probe the structure of the individual constituents of complexes. Studies comparing the relative stabilities of protein-ligand complexes in solution and desolvated in the gas phase will also be presented, and discussed from both fundamental and analytical perspectives.
    Electron-capture dissociation
    Biopolymer
    Infrared multiphoton dissociation
    Ion cyclotron resonance
    Non-covalent interactions
    Electron-transfer dissociation
    Citations (0)
    Methods are being developed for ultrasensitive protein characterization based upon electrospray ionization (ESI) with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The sensitivity of a FTICR mass spectrometer equipped with an ESI source depends on the overall ion transmission, which combines the probability of ionization, transmission efficiency, and ion trapping in the FTICR cell. Our developments implemented in a 3.5 tesla FTICR mass spectrometer include introduction and optimization of a newly designed electrodynamic ion funnel in the ESI interface, improving the ion beam characteristics in a quadrupole-electrostatic ion guide interface, and modification of the electrostatic ion guide. These developments provide a detection limit of approximately 30 zmol (∼18 000 molecules) for proteins with molecular weights ranging from 8 to 20 kDa.
    Ion cyclotron resonance
    Top-down proteomics
    Selected ion monitoring
    Hybrid mass spectrometer
    Quadrupole mass analyzer
    Citations (161)
    We report the coupling of a hybrid ionization source, matrix-assisted laser desorption electrospray ionization (MALDESI), to a Fourier transform-ion cyclotron resonance mass spectrometer (FT-ICR MS). The details of the source design and initial data are presented. Analysis of peptides and proteins ranging from 1 to 8.6 kDa resulted in high resolving power single-acquisition FT-ICR mass spectra with average charge-states highly correlated to those obtained by nanoESI, thus, providing strong evidence that the ESI process dictates the observed charge-state distribution. Importantly, unlike the recently introduced electrospray assisted laser desorption ionization (ELDI) source reported by Shiea and coworkers [1, 2], the data we have obtained to date rely on the use of an organic acid matrix. The results presented herein provide insight into the charging mechanism of this emerging ionization approach, while also expanding the utility of FT-ICR MS for top-down protein and complex mixture analysis.
    Ion cyclotron resonance
    Ambient ionization
    Top-down proteomics
    Desorption electrospray ionization
    MALDI imaging
    Atmospheric-pressure laser ionization
    Citations (357)
    ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCapillary Electrophoresis-Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Direct Analysis of Cellular ProteinsSteven A. Hofstadler, Franklin D. Swanek, David C. Gale, Andrew G. Ewing, and Richard D. SmithCite this: Anal. Chem. 1995, 67, 8, 1477–1480Publication Date (Print):April 15, 1995Publication History Published online1 May 2002Published inissue 15 April 1995https://pubs.acs.org/doi/10.1021/ac00104a028https://doi.org/10.1021/ac00104a028research-articleACS PublicationsRequest reuse permissionsArticle Views314Altmetric-Citations105LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
    Ion cyclotron resonance
    Top-down proteomics
    Capillary electrophoresis–mass spectrometry
    Selected ion monitoring
    Citations (125)
    Nano-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (nano-ESI-FTICRMS) was employed for the analysis of the phytosiderophore 2'-deoxymugineic acid (DMA) and the candidate ligand for the intracellular iron transport in plants nicotianamine (NA). Due to the zwitterionic nature of NA and DMA, complementary mass spectra were obtained in positive and negative ionization modes. The technique was also used for speciation of their complexes with Fe(II) and Fe(III), respectively. The species observed at pH 7.3 are the 1:1 Fe-ligand complexes and no evidence for the existence of dimeric complexes was observed. NA and DMA differ only by one mass unit. Consequently, in the system NA + DMA + Fe(II)/Fe(III), there are pairs of iron species (i.e. NA-Fe(II) and DMA-Fe(III)) with the same nominal mass, which differ only by approximately 0.02 mass units. It is shown that high-resolution MS accompanied by accurate mass data analysis allows the unequivocal identification of all four iron species (NA-Fe(II), NA-Fe(III), DMA-Fe(II), DMA-Fe(III)) in one solution without separation. We also addressed the possible alteration of the oxidation state of chelated iron under nano-ESI conditions, but no redox reactions were observed under optimized conditions.
    Ion cyclotron resonance
    Citations (32)
    Mass spectrometry has become an important tool for analysis of protein complexes. This study utilizes electrospray ionization (ESI) coupled to a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) to analyze noncovalent complexes in the gas phase. Binding of cucurbit[7]uril (CB7) to intact bovine insulin and the B-chain of insulin was investigated. Competition experiments involving the B-chain and a mutant B-chain were performed to probe the solution-phase binding site. Electron capture dissociation (ECD) of CB7 complexed to intact insulin and to the B-chain, produced a series of peptidic fragments of insulin in complex with CB7. Analysis of these fragments allowed the determination of the apparent gas-phase binding site, which appears different than the proposed solution-phase binding-site. These studies thus suggest that CB7 migrates when the complex is transferred from solution to gas phase. The results of this study caution against using ECD-MS as a stand-alone structural probe of solutionphase binding.%%%%MAST
    Ion cyclotron resonance
    Electron-capture dissociation
    Top-down proteomics
    Non-covalent interactions
    Citations (0)
    Abstract Fourier transform ion cyclotron resonance mass spectrometry equipped with electrospray ionization (ESI FT ICR MS) was successfully applied to determine molecular formulas of components in Arabian mix vacuum residue (AM-VR) by measurement of highly accurate m/z values of molecular ions and analysis of spectral pattern without any pre-separation procedures.
    Ion cyclotron resonance
    Residue (chemistry)
    Citations (12)