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ABSTRACT: Direct comparision of two ionization techniques, 252Cf plasma-desorption and electron-avalanche-desorption, is given in various aspect. signification differences were observed in the low-mass region, and in the spectra of volatile compounds and CsI samples, as well as in the fragmentation pattern of alanilnorleucine. On the other hand, a rather high degree of similarity was obtained in spectra of nitrocellulose and some cyclic depsipeptides, both in typical values of peak width and of the high-mass background character. The conclusion is made, that electron-avalanche desorption is a rather complex process involving various factors.
Rapid Communications in Mass Spectrometry 04/2005; 5(6):278 - 282. · 2.79 Impact Factor
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ABSTRACT: A new ionization technique based on a modification of the conventional plasma-desorption mass spectrometric apparatus is described. An electron avalanche produced by the microchannel plates of a secondary electron multiplier is found to desorb a sufficient amount of (quasi-)molecular ions of non-volatile thermally labile molecules. Spectra of several substances with molecular masses up to 1250 u are presented. The mechanism of electron avalanche desorption is now under investigation.
Rapid Communications in Mass Spectrometry 04/2005; 5(1):32 - 34. · 2.79 Impact Factor
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ABSTRACT: A new on-target deuteration technique in plasma desorption mass Spectrometry (PDMS) is proposed, involving replacing labile hydrogen atoms in a molecule with deuterium atoms. This technique is very simple and allows direct comparison of spectra before and after deuteration for the same probe. The utility of the deuteration procedure in PDMS has been demonstrated in obtaining additional information on the structure of a molecule and its fragments and on the mechanism of quasi-molecular ion formation.
Biological Mass Spectrometry 04/2005; 26(9):765 - 769. · 3.41 Impact Factor
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ABSTRACT: Details of a nitrocellulose (NC) substrate preparation technique in 252Cf plasma desorption time-of-flight mass spectrometry were investigated using an electrospray device, in which a micropump was employed for solution delivery. The molecular ion yields for three standard proteins (porcine insulin, chicken-egg lysozyme and chymotrypsinogen A) were studied as a function of the electrosprayed NC layer thickness, spray rate, NC solution concentration and some other parameters. Optimal parameters of the NC substrate preparation procedure were determined, which include deposition of a layer of 250-750 micrograms cm-2 at up to 15 microliters min-1 spray rate and up to 15 micrograms microliters-1 solution concentration.
Biological Mass Spectrometry 08/1992; 21(7):323-30.
