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Latest Paper:
Anal Chem. 2011 Sep 1;:
21882839
We present a novel, hybrid ion trap/time-of-flight mass spectrometer that is based on a planar multipole design. Compared with Paul trap/time-of-flight instruments, this design possesses the principal advantages of higher injection efficiency and more homogeneous extraction fields. We demonstrate the viability of the concept and describe the characterization of a first prototype. Ions can be injected into the trap with little mass discrimination and stored for several minutes. A resolution of over 1300 is achieved in reflectron mode, and the influence of the RF amplitude and pressure on the resolution is analyzed. We suggest several applications in which this new instrument could offer advantages over existing technology.
Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland.
We present here the design of a new tandem mass spectrometer that combines an electrospray ion source with a cryogenically cooled ion trap for spectroscopic studies of cold, gas-phase ions. The ability to generate large ions in the gas phase without fragmentation, cool them to approximately 10 K in an ion trap, and perform photofragment spectroscopy opens up new possibilities for spectroscopic characterization of large biomolecular ions. The incorporation of an ion funnel, together with a number of small enhancements, significantly improves the sensitivity, signal stability, and ease of use compared with the previous instrument built in our laboratory.
J Phys Chem A. 2010 Jan 19;:
20085359
Cit:2
Institut fur Optik und Atomare Physik, Technische Universitat Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany, Institut fur Chemie und Biochemie, Freie Universitat Berlin, Takustrasse 3, 14195 Berlin, Germany, Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne, EPFL SB ISIC LCPM, Station 6, CH-1015 Lausanne, Switzerland, and Laboratoire de Chimie Physique, Faculte des Sciences, Universite Paris-Sud 11, UMR8000 CNRS, Faculte des Sciences, Bat. 350, 91405 Orsay Cedex, France.
Cationic zirconocene complexes are active species in Ziegler-Natta catalysis for olefin polymerization. Their structure and metal-ligand bond strength strongly influence their activity. In the present work, the infrared multiphoton dissociation (IRMPD) spectrum of mass selected Zr(C(5)H(5))(2)(OH)(CH(3)CN)(+) cations was obtained in the 300-1500 cm(-1) fingerprint range by coupling a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer equipped with an electrospray ionization (ESI) source and the infrared free electron laser (IR-FEL) at the Centre Laser Infrarouge d'Orsay (CLIO). The experimental efforts are complemented by quantum chemical calculations at the MP2 and B3LYP levels using the 6-311G* basis set. Vibrational assignments of transitions observed in the IRMPD spectra to modes of the Zr-O-H, C(5)H(5), and CH(3)CN moieties are based on comparison to calculated linear absorption spectra. Both the experimental data and the calculations provide unprecedented information about structure, metal-ligand bonding, charge distribution, and binding energy of the complex.
Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland.
We report here a new technique for spectroscopic studies of protonated, gas-phase biomolecules and demonstrate its utility by measuring highly resolved electronic and infrared spectra of peptides of up to 17 amino acids. After UV excitation of an aromatic chromophore of a protonated peptide, a CO(2) laser further excites the molecules, increasing their vibrational energy and hence their dissociation rate, allowing detection of the UV excitation by monitoring the resulting photofragments. We show that addition of the CO(2) laser excitation increases the fragmentation yield on the time scale of our experiments by as much as 2 orders of magnitude, significantly enhancing the sensitivity of UV photofragment spectroscopy. We also demonstrate that this approach can be applied in an IR-UV double-resonance scheme, allowing measurement of conformer-specific infrared spectra of protonated peptides.
Yong Yu,
Andrew D Bond,
Philip W Leonard,
Ulrich J Lorenz,
Tatiana V Timofeeva,
K Peter C Vollhardt,
Glenn D Whitener,
Andrey A Yakovenko
Department of Chemistry, University of California at Berkeley, and the Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, USA. kpcv@berkeley.edu.
Hexaferrocenylbenzene has been synthesized by six-fold Negishi type ferrocenylation of hexabromo- or hexaiodobenzene.
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