The first experiment on the decharging of a complex plasma in microgravity conditions was conducted. After switching off the rf power, in the afterglow plasma, ions and electrons rapidly recombine and leave a cloud of charged microparticles. Because of microgravity, the particles remain suspended in the experimental chamber for a sufficiently long time, allowing precise measurements of the rest particle charge. A simple theoretical model for the decharging is proposed which agrees quite well with the experiment results and predicts the rest charge at lower gas pressures.
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http://dx.doi.org/10.1103/PhysRevLett.90.055003 | DOI Listing |
J Am Soc Mass Spectrom
June 2021
Division of BioAnalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Trapped ion-mobility spectrometry combined with quadrupole time-of-flight mass spectrometry (TIMS-QTOFMS) was evaluated as a tool for resolving linear and branched isomeric polyester oligomers. Solutions of polyester samples were infused directly into the ion source employing electrospray ionization (ESI). TIMS-MS provides both mobility and / data on the formed ions, allowing construction of extracted-ion mobilograms (EIMs).
View Article and Find Full Text PDFPhys Chem Chem Phys
August 2019
Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, 79104 Freiburg im Breisgau, Germany.
With application to the nitrite reductase hexameric protein complex of Desulfovibrio vulgaris, NrfH2A4, we suggest a strategy to compute the energy landscape of electron transfer in large systems of biochemical interest. For small complexes, the energy of all electronic configurations can be scanned completely on the level of a numerical solution of the Poisson-Boltzmann equation. In contrast, larger systems have to be treated using a pair approximation, which is verified here.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
May 2018
Human Health Therapeutics, National Research Council Canada, Ottawa, Ontario, Canada, K1A 0R6.
Mass spectrometry (MS) has played a vital role across a broad range of fields and applications in proteomics. The development of high-resolution MS has significantly advanced biology in areas such as protein structure, function, post-translational modification and global protein dynamics. The two most widely used MS ionization techniques in proteomics are electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI).
View Article and Find Full Text PDFAnalyst
March 2017
Waters Corporation, Milford, MA 010757, USA.
We demonstrate an integrated microfluidic LC device coupled to a QTOF capable of improving sensitivity and linearity for intact protein analysis while also tuning the charge state distributions (CSD) of whole antibodies. The mechanism for sensitivity improvement using microflow ESI is demonstrated by shifting of the CSD to higher charge state, and narrowing of the overall CSD. Both of these aspects serve to improve ion current of the most abundant charge state of antibodies and lead to improvement in sensitivity over high flow ESI by a factor of 15×.
View Article and Find Full Text PDFJ Proteome Res
May 2010
Institute of Computer Sciences, Free University Berlin, Berlin, Germany.
In electrospray ionization mass spectrometry (ESI-MS), peptide and protein ions are usually observed in multiple charge states. Moreover, adduction of the multiply charged species with other ions frequently results in quite complex signal patterns for a single analyte, which significantly complicates the derivation of quantitative information from the mass spectra. Labeling strategies targeting the MS1 level further aggravate this situation, as multiple biological states such as healthy or diseased must be represented simultaneously.
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