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Sökning: WFRF:(Budnik BA)

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1.
  • Balakin, AA, et al. (författare)
  • Polymer track membranes for extraction of ions from aqueous solutions at atmospheric pressure
  • 2002
  • Ingår i: EUROPEAN JOURNAL OF MASS SPECTROMETRY. - : SAGE Publications. - 1469-0667 .- 1751-6838. ; 8:2, s. 79-84
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The possibility of the application of the electromembrane technique for production of ions of biological molecules at atmospheric pressure is demonstrated. This technique has previously only been used for extraction of ions from liquids directly into vacuum. The membrane technique for ion extraction at atmospheric pressure was tested with both time-of-flight and Fourier transform ion cyclotron resonance mass spectrometers. The mass spectra of intact molecular ions obtained from aqueous solutions of peptides and proteins are presented. The possible mechanisms of non-destructive ion extraction are discussed. The new technique is promising for achieving absolute sensitivity (charging every analyte molecule) and for performing spatially-resolved analysis of liquid biological samples.
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  • Haselmann, KF, et al. (författare)
  • Can the (M center dot-X) region in electron capture dissociation provide reliable information on amino acid composition of polypeptides?
  • 2002
  • Ingår i: EUROPEAN JOURNAL OF MASS SPECTROMETRY. - : SAGE Publications. - 1469-0667 .- 1751-6838. ; 8:6, s. 461-469
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • It has been suggested that small losses from reduced peptide molecular species in electron capture dissociation (ECD) could indicate the presence of certain amino acids [H.J. Cooper, R.R. Hudgins, K. Håkansson and A.G. Marshall, J. Am Soc. Mass Spectrom 13, 241 (2002)], similarly to immonium ions in high-energy collision-activated dissociation. The diagnostic value in ECD of the (M•–X) region (1 Da ≤ X ≤ 130 Da) was tested on several synthetic peptides. The insufficiency of the existing knowledge for making correct conclusions on the amino acid composition is demonstrated and new suggestions of the origin of losses are presented based on the “hot hydrogen atom” ECD mechanism. Generally, it is shown that not only protonation but also charge solvation is responsible for the small losses. The origin of 17 Da and 59 Da losses is revisited and a new mechanism for the 18 Da loss is suggested. The loss of a side chain plus a hydrogen atom is found to be a rather reliable indicator of the presence of histidine, tryptophan, tyrosine and, to a lesser degree, threonine. The overall conclusion is that the (M• - X) region does contain information on the amino acid composition, but extraction of this information requires additional studies.
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  • Haselmann, KF, et al. (författare)
  • Electronic excitation gives informative fragmentation of polypeptide cations and anions
  • 2002
  • Ingår i: EUROPEAN JOURNAL OF MASS SPECTROMETRY. - : SAGE Publications. - 1469-0667 .- 1751-6838. ; 8:2, s. 117-121
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • A Fourier transform mass spectrometer is a versatile instrument with a range of available fragmentation techniques. Comparison of polypeptide fragmentation patterns revealed that the techniques involving electronic excitation, such as hot-electron-capture dissociation (HECD) and electron-detachment dissociation (EDD), are even more informative than vibrational excitation (VE) techniques such as collisional activation. For dications of the peptide KIMHASELMANN, 11 eV HECD cleaved all inter-residue links in at least two places, with up to five fragments characterizing each link. For dianions of the same molecule, VE produced only one backbone cleavage whereas EDD gave ten, including five internal cleavage fragments. This is consistent with the general postulate that homogeneous electronic excitation yields more types of cleavage than near-equilibrium processes such as VE.
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  • Zubarev, RA, et al. (författare)
  • Tandem ionization mass spectrometry of biomolecules
  • 2000
  • Ingår i: EUROPEAN JOURNAL OF MASS SPECTROMETRY. - : SAGE Publications. - 1469-0667 .- 1751-6838. ; 6:3, s. 235-240
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • The novel mass spectrometric technique tandem ionization mass spectrometry (TIMS) employs irradiation of gas-phase even-electron molecular ions of both polarities with >10 eV electrons. This leads to the production of radical molecular cations and anions of large biomolecules. The parent even-electron ions are produced by laser desorption, matrix-assisted laser desorption/ionization (UV and IR) or electrospray ionization and trapped in the cell of a Fourier transform mass spectrometer before irradiation with electrons. For multiply-charged polypeptide cations (up to 16+ for cytochrome c) and di-anions, TIMS produced radical [M + nH]( n + 1)+• cations and previously unreported [M − 2H]−• anions, respectively. Subsequent collisional activation of these species, in contrast to their even electron counterparts, gave only small neutral losses (mainly CO2) regardless of the ionic charge, polarity or lability. This process was rationalized through intramolecular hydrogen atom transfer in cations. Measurements of the threshold energies for electron ejection has now been extended to the protonated porphyrin C76H94N4 [ IE(MH+) = 12.8 ± 0.3 eV] and to multiply-charged polypeptide cations and anions. Serendipitously, it was found that, in the absence of electrons, [M + nH]( n + 1)+• polypeptide cations can also be formed in energetic collisions during the ion isolation process in Fourier transform mass spectrometry.
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