Resonance ionization mass spectroscopy

A reevaluation of molecular structure of humic substances based on data obtained primarily from nuclear magnetic resonance spectroscopy, X-ray absorption near-edge structure spectroscopy, electrospray ionization-mass spectrometry, and pyrolysis studies was presented by Sutton and Sposito (2005). The authors consider that humic substances are collections of diverse, relatively low molecular mass components forming dynamic associations stabilized by hydrophobic interactions and hydrogen bonds. These associations are capable of organizing into micellar structures in suitable aqueous environments. Humic components display contrasting molecular motional behavior and may be spatially segregated on a scale of nanometers. Within this new structural context, these components comprise any molecules... 

Resonant and non-resonant laser post-ionization of sputtered uranium atoms using SIRIS (sputtered initited resonance ionization spectroscopy) and SNMS (secondary neutral mass spectrometry) in one instrument for the characterization of sub-pm sized single microparticles was suggested by Erdmann et al.94 Resonant ionization mass spectrometry allows a selective and sensitive isotope analysis without isobaric interferences as demonstrated for the ultratrace analysis of plutonium from bulk samples.94 Unfortunately, no instrumental equipment combining both techniques is commercially available. 

Hi) Methods based on mass spectrometry Spark-source mass spectrometry Glow-discharge mass spectrometry Inductively coupled-plasma mass spectrometry Electro-thermal vaporization-lCP-MS Thermal-ionization mass spectrometry Accelerator mass spectrometry Secondary-ion mass spectrometry Secondary neutral mass spectrometry Laser mass spectrometry Resonance-ionization mass spectrometry Sputter-initiated resonance-ionization spectroscopy Laser-ablation resonance-ionization spectroscopy... 

There are only a few reports on the structures of active oxygen species formed on POMs. Recently, we have clarified some of the structures of the active oxygen species formed on POMs with nuclear magnetic resonance (NMR) spectroscopy, coldspray ionization mass spectrometry (CSI-MS), and single crystal X-ray structural analysis. In this section, we focus on the activation of H2O2 by the species (a)-(c) and present results from our recent studies. Some reaction mechanisms for H2O2-based oxidations by POMs are also described. 

Erdmann, N., Nunnemann, M., Eberhardt, K., Herrmann, G., Huber, G., Kohler, S., Kratz, J. V., Passler, G., Peterson, J. R., Trautmann, N., and Waldek, A. 1998. Determination of the first ionization potential of nine actinide elements by resonance ionization mass spectroscopy (RIMS). J Alloys Compd 271, 837-840. 

Herrmann, G., Riegel, J., Rimke, H., Sattelberger, P, Trautmann, N., Urban, E J., Ames, E, Otten, E. W., Ruster, W., and Scheerer, F. 1991. Resonance ionization mass-spectroscopy of uranium. Inst Phys ConfSer (114), 251-254. 

In atomic laser spectroscopy, the laser radiation, which is tuned to a strong dipole transition of the atoms under investigation, penetrates the volume of species evaporated from the sample. The presence of analyte atoms can be measmed by means of the specific interaction between atoms and laser photons, such as by absorption techniques (laser atomic absorption spectrometry, LAAS), by fluorescence detection (laser-induced fluorescence spectroscopy, LIFS), or by means of ionization products (electrons or ions) of the selectively excited analyte atoms after an appropriate ionization process (Figures lA and IB). Ionization can be achieved in different ways (1) by interaction with an additional photon of the exciting laser or of a second laser (resonance ionization spectroscopy, RIS, or resonance ionization mass spectrometry, RIMS, respectively, if combined with a mass detection system) (2) by an electric field applied to the atomization volume (field-ionization laser spectroscopy, FILS) or (3) by collisional ionization by surrounding atoms (laser-enhanced ionization spectroscopy, LEIS). 

LEIS laser-enhanced ionization spectroscopy FILS field ionization laser spectroscopy RIS resonance ionization spectroscopy RIMS resonance ionization mass spectrometry... 

During the last decades methods such as Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), and Resonance Ionization Mass spectrometry (RIMS) have decreased the need for selective radiochemical procedures. Many long-lived radionuclides today have lower detection limits if using, e.g., ICP-MS than if performing radiometric measurements with reasonable measuring times. At present, the half-life limit is a few hundred years, i.e., nuclides with longer half-hfe (e.g., Tc, Np, or Pu) should preferably be measured by ICP-MS and more short-... 

In other articles in this section, a method of analysis is described called Secondary Ion Mass Spectrometry (SIMS), in which material is sputtered from a surface using an ion beam and the minor components that are ejected as positive or negative ions are analyzed by a mass spectrometer. Over the past few years, methods that post-ion-ize the major neutral components ejected from surfaces under ion-beam or laser bombardment have been introduced because of the improved quantitative aspects obtainable by analyzing the major ejected channel. These techniques include SALI, Sputter-Initiated Resonance Ionization Spectroscopy (SIRIS), and Sputtered Neutral Mass Spectrometry (SNMS) or electron-gas post-ionization. Post-ionization techniques for surface analysis have received widespread interest because of their increased sensitivity, compared to more traditional surface analysis techniques, such as X-Ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES), and their more reliable quantitation, compared to SIMS. 

Sputter-Initiated Resonance Ionization Spectroscopy Surface Analysis by Resonant Ionization Spectroscopy Time-of-Flight Mass Spectrometer... 

Infrared, ultraviolet, and nuclear magnetic resonance spectroscopies differ from mass spectrometry in that they are nondestructive and involve the interaction of molecules with electromagnetic energy rather than with an ionizing source. Before beginning a study of these techniques, however, let s briefly review the nature of radiant energy and the electromagnetic spectrum. 

Note The acronyms used here are OSPED (optical spectroscopy in a pulsed electrical discharge), FAMS (flowing afterglow mass spectrometry), SIFT (selected ion flow tube), TRAPI (time-resolved atmospheric pressure ionization mass spectrometry), PHPMS (pulsed high-pressure ionization mass spectrometry), ICRMS (ion cyclotron resonance mass spectrometry), and ADO (averaged dipole orientation collision rate theory). 

F. H. Field, Chemical Ionization Mass Spectroscopy, Accts. Chem. Res. 1,42 (1968). Ion-Cyclotron Resonance Spectroscopy... 

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