Search results for " ionization"
showing 10 items of 621 documents
Use of Ambient Ionization High-Resolution Mass Spectrometry for the Kinetic Analysis of Organic Surface Reactions
2016
In contrast to homogeneous systems, studying the kinetics of organic reactions on solid surfaces remains a difficult task due to the limited availability of appropriate analysis techniques that are general, high-throughput, and capable of offering quantitative, structural surface information. Here, we demonstrate how direct analysis in real time mass spectrometry (DART-MS) complies with above considerations and can be used for determining interfacial kinetic parameters. The presented approach is based on the use of a MS tag that - in principle - allows application to other reactions. To show the potential of DART-MS, we selected the widely applied strain-promoted alkyne-azide cycloaddition …
Lanthanide complexation with CMPO and CMPO-calix[4]arenes in solution: spectrophotometric and electrospray mass spectrometric approaches.
2007
The binding of lanthanide(III) cations with organophosphorous ligands like CMPO and related calix[4]arene-based derivatives have been investigated using two experimental methods. The stability constants of the lanthanum, europium and ytterbium complexes were first determined in methanol by UV absorption spectrophotometry in the presence of nitrate or chloride anions. The results showed that the stoichiometry and the stability of the complexes formed depend on the position of the CMPO moieties either on the wide or the narrow rim of the calixarene scaffold, the nature of the medium, the conformational mobility of the ligands. Complexation of lanthanum was also followed by ESI-mass spectromet…
On-line implementation and first operation of the Laser Ion Source and Trap at ISOLDE/CERN
2015
13 pags.; 12 figs.; 2 tab.; Open Access funded by CERN
RAPTOR : A new collinear laser ionization spectroscopy and laser-radiofrequency double-resonance experiment at the IGISOL facility
2023
RAPTOR, Resonance ionization spectroscopy And Purification Traps for Optimized spectRoscopy, is a new collinear resonance ionization spectroscopy device constructed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyv\"askyl\"a, Finland. By operating at beam energies of under 10 keV, the footprint of the experiment is reduced compared to more traditional collinear laser spectroscopy beamlines. In addition, RAPTOR is coupled to the JYFLTRAP Penning trap mass spectrometer, opening a window to laser-assisted nuclear-state selective purification, serving not only the mass measurement program, but also supporting post-trap decay spectroscopy experiments. Finally,…
Resonance laser ionization developments for IGISOL-4
2012
The work presented in this thesis concentrates on the development of the FURIOS laser ion source towards e cient and selective production of low energy radioactive ion beams. This includes design and development of the ion guide and hot cavity catcher systems for laser ion source use, and the development of in-source and in-jet laser spectroscopy techniques. The work has been carried out at the IGISOL facility in the Accelerator laboratory of the University of Jyväskylä. The FURIOS facility was upgraded and developed during the move to the IGISOL-4 facility. The laser transport was greatly improved in order to allow a large fraction of the initial laser intensity to be transported into the …
Synthesis, characterization and crystal structures of polymeric and dimeric triphenyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(2-carboxyphe…
2005
Abstract The triphenyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(2-carboxyphenyl)-1-diazenyl]phenyl}methylidene)amino]aryls (aryls = 4-CH3, 4-Br, 4-Cl, 4-OCH3) have been synthesized and characterized by 1H-, 13C-, 119Sn-NMR, ESI mass spectrometry, IR and 119mSn Mossbauer spectroscopic techniques in combination with elemental analysis. The crystal structures of a representative carboxylate ligand (aryl = 4-CH3) and three Sn complexes, viz., polymeric (Ph3Sn[O2CC6H4{N N(C6H3-4-OH(C(H) NC6H4X-4))}-o])n (X = Me (1) and Br (2)) and dimeric (Ph3Sn[O2CC6H4{N N(C6H3-4-OH(C(H) NC6H4X-4))}-o])2 (X = OMe (4)) complexes are reported. The coordination environment in each complex is trigonal bip…
Light Dark Matter Search with Ionization Signals in XENON1T
2019
We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4 keVee, we observe <1 event/(tonne day keVee), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses mχ within 3–6 GeV/c2, DM-electron scattering for mχ>30 MeV/c2, a…
High Performance Liquid Chromatografy-Mass Spectrometry based chemometric characterization of olive oils
2005
In this study the effective discrimination of extra virgin olive oils is described using HPLC-MS, combined with chemometric evaluation. The presented method is simple since the diluted oil sample is directly injected into the system, without any preliminary chemical derivatization or purification step. Separation of diacylglycerols, triacylglycerols and sterols occurs within 20 min and is achieved using an octadecyl-silica column. Detection is performed by positive APCI mass spectrometry which provided sensitivity to detect over 50 compounds in the sample. After extraction of data, stepwise discriminant function analysis is used to select the variables with the highest discriminative power.…
Structure of a polysaccharide from the lipopolysaccharides of Vibrio vulnificus strains CECT 5198 and S3-I2-36, which is remarkably similar to the O-…
2009
High-molecular-mass polysaccharides were released by mild acid degradation of the lipopolysaccharides of two wild-type Vibrio vulnificus strain, a flagellated motile strain CECT 5198 and a non-flagellated non-motile strain S3-I2-36. Studies by sugar analysis and partial acid hydrolysis along with (1)H and (13)C NMR spectroscopies showed that the polysaccharides from both strains have the same trisaccharide repeating unit of the following structure: --4)-beta-d-GlcpNAc3NAcylAN-(1--4)-alpha-l-GalpNAmA-(1--3)-alpha-d-QuipNAc-(1--where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose, GalNAmA for 2-acetimidoylamino-2-deoxygalacturonic acid, GlcNAc3NAcylAN for 2-acetamido-3-acylamino-2,3-dideoxy…
Core oligosaccharide of Escherichia coli B—the structure required for bacteriophage T4 recognition
2015
Abstract The structure of Escherichia coli B strain PCM 1935 core oligosaccharide has been investigated by 1H and 13C NMR spectroscopy, MALDI-TOF MS and ESI MSn. It was concluded that the core oligosaccharide is a pentasaccharide with the following structure: ESI MS/MS analysis revealed that the glycine (a minor component) is linked to the →3,7)- l -α- d -Hepp-(1→ residue.