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Schelev M.Ya.,RAS A.M. Prokhorov General Physics Institute | Andreev S.V.,RAS A.M. Prokhorov General Physics Institute | Greenfield D.E.,ThermoFisher Scientific Bremen GmbH | Degtyareva V.P.,RAS A.M. Prokhorov General Physics Institute | And 2 more authors.
Quantum Electronics | Year: 2015

Numerical modelling is used to analyse some effects restricting the enhancement of temporal resolution into the area better than 100 fs in streak image tubes and photoelectron guns. A particular attention is paid to broadening of an electron bunch as a result of Coulomb interaction. Possible ways to overcome the limitations under consideration are discussed. © 2015 Kvantovaya Elektronika and Turpion Ltd. Source


Skoblin M.G.,RAS Institute of Problems of Chemical Physics | Kopaev I.A.,RAS A.M. Prokhorov General Physics Institute | Greenfield D.E.,ThermoFisher Scientific Bremen GmbH | Makarov A.A.,ThermoFisher Scientific Bremen GmbH | And 2 more authors.
Quantum Electronics | Year: 2015

General theoretical approaches to the modelling of Coulomb effects in short ion bunches, developed previously by the authors, are applied in this paper to the calculation of multireflection mass-spectrometer systems. A separate module of the MASIM 3D applied software package is designed. An adaptive computational procedure for calculating the 'mirror potential' induced by an ion bunch on the surface of field-forming electrodes is proposed. The dynamics of ion bunches in a time-of-flight reflectron-type mass analyser is calculated and the limitations on the resolving power, caused by resonant Coulomb effects of self-bunching and coalescence in the groups of particles with close masses, are revealed on the basis of numerical experiments. © 2015 Kvantovaya Elektronika and Turpion Ltd. Source


Lebedev A.T.,Moscow State University | Damoc E.,ThermoFisher Scientific Bremen GmbH | Makarov A.A.,ThermoFisher Scientific Bremen GmbH | Samgina T.Y.,Moscow State University
Analytical Chemistry | Year: 2014

An efficient approach to easy and reliable differentiation between isomeric leucine and isoleucine in peptide sequencing utilizes multistage electron transfer dissociation and higher energy collision activated dissociation in the Orbitrap Fusion mass spectrometer. The MS3 method involves production and isolation of primary odd-electron z• ions, followed by radical site initiation of their fragmentation with formation of w-ions, characteristic of the isomeric amino acid residues. Six natural nontryptic peptides isolated from the secretion of frog Rana ridibunda were studied. Their lengths were in the range between 15 and 37 amino acids and the number of targeted isomeric (Leu/Ile) residues varied between 1 and 7. The experiments were successful in all 22 cases of Leu/Ile residues, leaving no doubts in identification. The method is extremely selective as the targeted w-ions appear to be the most intense in the spectra. The proposed approach may be incorporated into shotgun proteomics algorithms and allows for the development of an exclusively mass spectrometric method for automated complete de novo sequencing of various peptides and proteins. © 2014 American Chemical Society. Source


Makarov A.A.,RAS A.M. Prokhorov General Physics Institute | Grechnikov A.A.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Nikiforov S.M.,RAS A.M. Prokhorov General Physics Institute | Tyutyunnik O.A.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Denisov E.V.,ThermoFisher Scientific Bremen GmbH
Journal of Analytical Chemistry | Year: 2013

The results of a study on interfacing an Orbitrap mass analyzer with direct ion injection to a surface assisted laser desorption/ionization (SALDI) ion source are presented. Osmium complexes with 8-mercaptoquinoline were studied. Titanium oxide thin films prepared by electron beam evaporation were found an effective emitter of the ions of the test complexes. It was demonstrated that interfacing the Orbitrap mass analyzer to a SALDI source can significantly improve the analytical performance of this method in comparison to a typical combination of SALDI/time-of-flight mass spectrometer. © 2013 Pleiades Publishing, Ltd. Source

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