scholarly journals Pulsed laser desorption method for volatilizing thermally labile molecules for supersonic jet spectroscopy

1988 ◽  
Vol 59 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Liang Li ◽  
David M. Lubman
Keyword(s):  
Supersonic Jet ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Desorption Method

Resonance-Enhanced Multiphoton Ionization Jet Spectroscopy and Mass Spectrometry of Tyrosine-Containing Dipeptides Using a Pulsed Laser Desorption/Volatilization Method

1989 ◽  
Vol 43 (3) ◽  
pp. 543-549 ◽  
Author(s):  
Liang Li ◽  
David M. Lubman
Keyword(s):  
Mass Spectrometer ◽  
Laser Energy ◽  
Multiphoton Ionization ◽  
Supersonic Jet ◽  
Time Of Flight ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Spectral Features ◽  
Flight Mass Spectrometer ◽  
Jet Cooling

Pulsed laser desorption is used as a means of volatilizing thermally labile tyrosine-containing dipeptides for entrainment into a supersonic jet expansion. The jet expansion provides ultracold molecules whose spectral features are probed by resonant two-photon ionization (R2PI) spectroscopy in a time-of-flight mass spectrometer. In the dipeptides studied, spectral contours ∼1.5 nm FWHM are observed. Although no sharp spectral features were obtained, the shape of the contour is quite distinctive, and isomeric dipeptides can be distinguished. In addition, the ions produced are monitored in a time-of-flight mass spectrometer. It is shown that soft ionization can be obtained for each of these dipeptides by optimizing the jet cooling and exciting at the maximum intensity of the specific origin transition. By an increase in the laser energy, fragmentation is produced which can be used for structural identification of each of these dipeptides. Other factors that may affect these results, such as thermal decomposition, are also investigated.

Resonant Two-Photon Ionization of CBZ-Derivatized Nonaromatic Peptides Using Pulsed Laser Desorption in Supersonic Beam Mass Spectrometry

1988 ◽  
Vol 42 (3) ◽  
pp. 411-417 ◽  
Author(s):  
Liang Li ◽  
David M. Lubman
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Small Peptides ◽  
Neutral Species ◽  
Supersonic Expansion ◽  
Two Photon ◽  
Photon Ionization ◽  
Desorption Method

Resonant two-photon ionization (R2PI) of nonaromatic peptides is studied with the use of CBZ-derivatization as a means of providing an absorbing aromatic center in the near-UV region at 266 nm. The peptides are then vaporized with a pulsed laser-induced desorption method, with subsequent entrainment of the desorbed neutral species into a supersonic expansion. The CBZ-derivatized peptides are then ionized and mass analyzed in a time-of-flight mass spectrometer. The resulting R2PI/MPI-induced fragmentation-ionization patterns generally yield the molecular ion as well as fragments due to specific bond cleavages which are characteristic of the structure of the peptide. Thus, the resulting mass spectra can be used for identification and structural analysis of these small peptides. Most significantly, the laser-induced fragmentation can be used to distinguish between isomeric peptides containing Ile, Leu, or Nle.

Analytical Jet Spectroscopy of Tyrosine and its Analogs Using a Pulsed Laser Desorption Volatilization Method

1988 ◽  
Vol 42 (3) ◽  
pp. 418-424 ◽  
Author(s):  
Liang Li ◽  
David M. Lubman
Keyword(s):  
Structural Changes ◽  
Electronic Spectroscopy ◽  
Supersonic Jet ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Ultracold Molecules ◽  
Two Photon ◽  
Biological Compounds ◽  
Supersonic Jet Expansion ◽  
Photon Ionization

Pulsed laser desorption is used as a means of volatilizing nonvolatile and thermally labile molecules for entrainment into a supersonic jet expansion. The jet expansion provides ultracold molecules whose sharp spectral features are probed by resonant two-photon ionization spectroscopy in a time-of-flight mass spectrometer. Such jet-cooled spectra are demonstrated for tyrosine and related structural analogs. Despite the similarity between these tyrosine-based compounds, electronic spectroscopy is shown to be a sensitive probe of small structural changes in these related biological compounds.

Resonant Two-Photon Ionization in Biomolecules Using Laser Desorption in Supersonic Beam-Mass Spectrometry

1987 ◽  
Vol 41 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Roger Tembreull ◽  
David M. Lubman
Keyword(s):  
Mass Spectra ◽  
Supersonic Jet ◽  
Pulsed Laser ◽  
Laser Desorption ◽  
Molecular Ions ◽  
Ceramic Surface ◽  
Soft Ionization ◽  
Two Photon ◽  
Photon Ionization ◽  
General Tool

Resonant two-photon ionization (R2PI) has been demonstrated for several classes of biomolecules in a supersonic jet. These thermally labile and nonvolatile species have been vaporized with pulsed laser desorption, with the use of a CO2 laser from a ceramic surface with subsequent entrapment in a jet expansion. R2PI is then demonstrated in a time-of-flight mass spectrometer (TOFMS) with the use of ultraviolet laser radiation at either 280 or 266 nm. The 280-nm wavelength is found to be a fairly general tool for exciting the π-π* transition of the molecules under study, viz., metabolites of catecholamines, indoleamines, and tyrosine near their respective origin regions. The resulting mass spectra exhibit soft ionization where either molecular ions or minimal fragmentation is produced. At frequencies of much higher energy than that of the origin, fragmentation becomes increasingly difficult to prevent.

A New Liquid Droplet Laser Desorption Source Combined with Supersonic Jet Expansion: Application to Phenol and its Water Clusters

2014 ◽  
Vol 228 (4-5) ◽  
Author(s):  
Chayan Kanti Nandi ◽  
Hans-Dieter Barth ◽  
Bernhard Brutschy
Keyword(s):  
Gas Phase ◽  
Water Clusters ◽  
Liquid Droplet ◽  
Supersonic Jet ◽  
Laser Desorption ◽  
Laser Source ◽  
Published Data ◽  
Two Photon ◽  
Supersonic Jet Expansion ◽  
Phase Out

AbstractWe have developed a new laser source, for the spectroscopy of nonvolatile molecules in gas phase. It is based on a laser induced liquid bead ion desorption source (LILBID) combined with a supersonic beam. The cold molecules produced with this technique are sampled with Resonant Two Photon Ionization spectroscopy (R2PI) to measurement of the gas phase optical spectra. LILBID allows to bring nonvolatile molecule from liquid phase (out of a droplet) into gas phase, by means of multi photon ablation with IR photons exciting the vibrations of the solvent. Phenol and its different water clusters have been used as an example to demonstrate the method and to standardise the new experimental setup. The recorded R2PI spectral data of phenol monomer and its different water clusters obtained from this laser desorption technique are in very good agreement with the previously published data. This technique opens a new door for the measurement of molecules under microsolvation and potentially for

Gas-phase segregation effects in pulsed laser desorption from binary targets

1993 ◽  
Vol 70 (12) ◽  
pp. 1886-1889 ◽  
Author(s):  
Herbert M. Urbassek ◽  
Dieter Sibold
Keyword(s):  
Gas Phase ◽  
Pulsed Laser ◽  
Phase Segregation ◽  
Laser Desorption
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