Desorption plasma

Plasma desorption (PD) was introduced by Mcfarlane and Torgesson [15]. In this ionization technique, the sample deposited on a small aluminized nylon foil is exposed in the source to the fission fragments of252Cf, having an energy of several mega-electronvolts. [Pg.32]

Mass spectrometric measurements of ions desorbed/ionized from a surface by a laser beam was first performed in 1963 by Honig and Woolston [151], who utilized a pulsed mby laser with 50 p,s pulse length. Hillenkamp et al. used microscope optics to focus the laser beam diameter to 0.5 p,m [152], allowing for surface analysis with high spatial resolution. In 1978 Posthumus et al. [153] demonstrated that laser desorption /ionization (LDI, also commonly referred to as laser ionization or laser ablation) could produce spectra of nonvolatile compounds with mass 1 kDa. For a detailed review of the early development of LDI, see Reference 154. There is no principal difference between an LDI source and a MALDI source, which is described in detail in Section 2.1.22 In LDI no particular sample preparation is required (contrary to [Pg.34]

which is LDI utilizing a particular sample preparation). Although the performance of MALDI is superior to LDI in the analysis of many groups of compounds, LDI is still the perferred choice in some important applications, including cmde oil analysis [155], fullerene detection in rocks [156], atmospheric aerosol analysis [157], semiconductors, and surface analysis [158]. Reference 21 is a comprehensive review of the use of LDI (and several other ion sources) in analysis of inorganics. [Pg.35]

There is a special case of LDI worth mentioning, desorption/ionization on silicon (DIOS) [159, 160], in which analyte compounds are deposited on a surface of etched silicon. With this substrate the mass range can be extended to a few kilodaltons, allowing for analysis of, for example, small peptides without the involvement of a matrix. [Pg.35]

Matrix-assisted laser desorption/ionization (MALDI) was developed by Karas, Hillenkamp, and coworkers in the late 1980s [161-163]. At the same time, a related technique was introduced by Tanaka et al. and involved mixing of the analyte with a very finely ground metal powder [164], [Pg.35]

The molecular ions produced in the MALDI process have relatively high initial velocities, which can cause reduction in mass resolving power and transmission, primarily for TOF analyzers with axial ion extraction (see Section 2.2.1). Hence, the MALDI-MS mass resolving power depends strongly on laser fluence and is highest when the laser fluence is close to the threshold level. [Pg.37]

Spectrometric Analysis. Remarkable developments ia mass spectrometry (ms) and nuclear magnetic resonance methods (nmr), eg, secondary ion mass spectrometry (sims), plasma desorption (pd), thermospray (tsp), two or three dimensional nmr, high resolution nmr of soHds, give useful stmcture analysis information (131). Because nmr analysis of or N-labeled amino acids enables determiaation of amino acids without isolation from organic samples, and without destroyiag the sample, amino acid metaboHsm can be dynamically analy2ed (132). Proteia metaboHsm and biosynthesis of many important metaboUtes have been studied by this method. Preparative methods for labeled compounds have been reviewed (133). [Pg.285]

Tuszynski, W. et al.. The observation of chlorophyll a aggregates with plasma desorption mass spectrometry, in Proceedings of the 5th International Conference of Ion Formation from Organic Solids (IFOS V), Hedin, A., Sundqvist, B.U.R. and Ben-ninghoven. A., Eds., Wiley, Chichester, England, 1989. [Pg.46]

An intense peak at m/e = 689, eonsistent with [Co(15b-H)2 ], was observed in the positive ion plasma desorption mass spectrum. [Pg.32]

Fast atom bombardment (FAB) Plasma desorption (PD) Liquid secondary-ion mass spectrometry (LSIMS) Thermospray (TSP)/plasmaspray (PSP) Electrohydrodynamic ionisation (EHI) Multiphoton ionisation (MPI) Atmospheric pressure chemical ionisation (APCI) Electrospray ionisation (ESI) Ion spray (ISP) Matrix-assisted laser desorption/ionisation (MALDI) Atmospheric pressure photoionisation (APPI) Triple quadrupole (QQQ) Four sector (EBEB) Hybrid (EBQQ) Hybrid (EB-ToF, Q-ToF) Tandem ToF-ToF Photomultiplier... [Pg.352]

In the plasma desorption (PD) technique, liquid matrices have also been used, but most samples are prepared as a thin-film solid. A solution of the... [Pg.384]

NP Normal phase PD-MS, PDMS Plasma-desorption mass... [Pg.758]

Okubo, M., Inoue, M., Kuroki, T. et al. (2005) NOx reduction after treatment system using nitrogen nonthermal plasma desorption, IEEE Trans. Ind. Appl. 41, 891-9. [Pg.395]

The introduction of soft ionization techniques, such as plasma desorption (PD),[1] field desorption (FD)[2] and fast atom bombardment (FAB),[3] marked the beginning of a new era for MS. In fact, they allowed MS to extend its applications to wide classes of nonvolatile, polar, thermally unstable and high molecular weight analytes. This opened up new horizons for MS in many unexpected fields, such as biology, biomedicine and biotechnology, in which this methodology had not previously found any possible application. [Pg.38]

Over the years, a lot of desorption ionization techniques have been introduced to MS, such as plasma desorption, field desorption, laser desorption, secondary ion mass spectrometry, fast atom bombardment, matrix assisted laser desorption and desorption electrospray ionization. Most of them are actually no longer used. In the following paragraphs, both matrix assisted laser desorption (MALDI) and desorption electrospray ionization (DESI) will be discussed. [Pg.51]

Plasma desorption PD Particle induced desorption/ ionization Nonvolatile molecular ions Soft method Large molecules... [Pg.18]

Pulsed ion sources for axial injection such as MALDI and SIMS, and earlier plasma desorption are suitable for TOF analyzers. For continuous ion sources such as ESI the oa configuration is suitable. [Pg.45]

G. Brinkmalm, P. Hakansson, J. Kjellberg, P. Demirev, B. U. R. Sundqvist, and W. Ens. A Plasma Desorption Time-of-Flight Mass Spectrometer with a Single-Stage Ion Mirror Improved Resolution and Calibration Procedure. Int. J. Mass Spectrom. Ion Proc., 114(1992) 183-207. [Pg.78]

G. Jonsson, A. Hedin, P. Hakansson, B. U. R. Sundqvist, H. Bennich, and P. Roepstorff. Compensation for Non-Normal Ejection of Large Molecular Ions in Plasma-Desorption Mass Spectrometry. Rapid Commun. Mass Spectrom., 3(1989) 190-191. [Pg.79]

B. Sundqvist and R. D. Macfarlane. 252Cf-Plasma Desorption Mass Spectrometry. Mass Spectrom. Rev., 4(1985) 421-460. [Pg.79]

See also in sourсe #XX -- [ Pg.359 , Pg.384 ]

See also in sourсe #XX -- [ Pg.238 ]

See also in sourсe #XX -- [ Pg.352 ]

See also in sourсe #XX -- [ Pg.114 ]

See also in sourсe #XX -- [ Pg.202 , Pg.203 ]

See also in sourсe #XX -- [ Pg.77 ]

See also in sourсe #XX -- [ Pg.657 ]

See also in sourсe #XX -- [ Pg.8 , Pg.15 , Pg.30 , Pg.32 , Pg.305 ]

See also in sourсe #XX -- [ Pg.72 ]

See also in sourсe #XX -- [ Pg.2 , Pg.9 , Pg.50 , Pg.487 ]

See also in sourсe #XX -- [ Pg.2 , Pg.9 , Pg.50 , Pg.487 ]

See also in sourсe #XX -- [ Pg.732 ]

See also in sourсe #XX -- [ Pg.332 ]

See also in sourсe #XX -- [ Pg.326 ]

See also in sourсe #XX -- [ Pg.30 ]

See also in sourсe #XX -- [ Pg.2 , Pg.8 ]

See also in sourсe #XX -- [ Pg.40 ]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...