Laser desorption mass spectrometry of nonvolatiles under shock wave conditions

Lindner, Buko; Seydel, Ulrich

doi:10.1021/ac00281a027

Cited by 107 publications

(74 citation statements)

References 29 publications

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“…Since LIAD is known to generate mostly neutral and intact molecules, this technique is well suited for softly producing pulses of low-polarity thermally-labile gas-phase molecules [11,13,14]. Initial studies describing the LIAD process suggested an acoustic wave mechanism for volatilization [15]. However, subsequent studies suggest a more complex mechanism where laser-induced stresses in the foil cause cracks in deposited molecular crystals and repulsive non-equilibrium electronic surface states, thus creating desorption sites from which analytes are ejected [12,16].…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas

Benham

Hodyss

Fernández

et al. 2016

J. Am. Soc. Mass Spectrom.

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Abstract. We demonstrate the first application of laser-induced acoustic desorption (LIAD) and atmospheric pressure photoionization (APPI) as a mass spectrometric method for detecting low-polarity organics. This was accomplished using a Lyman-α (10.2 eV) photon generating microhollow cathode discharge (MHCD) microplasma photon source in conjunction with the addition of a gas-phase molecular dopant. This combination provided a soft desorption and a relatively soft ionization technique. Selected compounds analyzed include α-tocopherol, perylene, cholesterol, phenanthrene, phylloquinone, and squalene. Detectable surface concentrations as low as a few pmol per spot sampled were achievable using test molecules. The combination of LIAD and APPI provided a soft desorption and ionization technique that can allow detection of labile, low-polarity, structurally complex molecules over a wide mass range with minimal fragmentation.

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Section: Introductionmentioning

confidence: 99%

Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas

Benham

Hodyss

Fernández

et al. 2016

J. Am. Soc. Mass Spectrom.

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“…Even considered that the terms "thermal" and "equilibrium process" are used with somewhat different meanings by different authors, the fundamental questio remains. Observation of "non volatile", large organic parent molecular ions with relative molecular masses above 1000 [18,21,22,29,31,36)and often very limited fragmentation supports the notion of a nonequilibrium process.Ver little is on the other hand known about the true volatility of most substances investigated and some of the improvements in the range of detected large ions also result from increased sensitivities of the instruments used. The prolonge ion emission over tens of microseconds as reported by COTTER(17, 18J, on the other hand, seems to rather support a therma1 model.…”

Section: Mechanisms Of Laser Desorptionmentioning

confidence: 73%

Laser Desorption Mass Spectrometry. A Review

Hillenkamp

1986

Springer Series in Chemical Physics

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“…This is because the analyte molecules tightly bind with silica gel, preventing the analyte molecules desorbing from the TLC plate. It is not difficult to desorb molecules of around 300-400 Da by direct laser irridation 12,13 as long as the analyte molecules have only a weak interaction with the silica gel and are present on the surface of the TLC plate. The SALDI liquid helps reduce the interaction between analyte and stationary phase besides being one of the components in the SALDI suspension.…”

Section: Resultsmentioning

confidence: 99%

In situ determination of organic reaction products by combining thin layer chromatography with surface-assisted laser desorption/ionization time-of-flight mass spectrometry

Chen

1999

Rapid Commun. Mass Spectrom.

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This study presents an in situ determination of organic reaction products on a thin layer chromatography (TLC) plate using surface-assisted laser desorption/ionization (SALDI) time-of-flight mass spectrometry. This technique can rapidly identify products and byproducts on an intact TLC plate. The characteristics of low matrix interference and low suppression effects in SALDI make this technique particularly appropriate for small organic compounds. In addition, the SALDI liquid used in the SALDI matrix system helps to reduce the interaction between analyte and silica gel on the TLC plate, thus avoiding an extra extraction procedure when preparing the sample. Furthermore, preparing the sample by combining TLC with SALDI mass spectrometry on the TLC plate is a relatively easy task. A TLC/SALDI analysis takes less than ten minutes to complete. Copyright # 1999 John Wiley & Sons, Ltd. Received 1 February 1999; Revised 5 March 1999; Accepted 5 March 1999 Thin layer chromatography (TLC) provides a fast and inexpensive separation method for purification. TLC is frequently used in the separation of reaction products in organic synthesis. Different visualization methods are conventionally used to identify reaction products in TLC. However, the reaction products are normally purified by column chromatography for further confirmation. The collected fraction is then analyzed by nuclear magnetic resonance (NMR). This procedure is quite tedious and timeconsuming. Mass spectrometry has been used as an alternative detection method to confirm organic reaction products after TLC separation. Ideally, the TLC plate should be directly inserted into the mass spectrometer for analysis when the separation is achieved. The plate is heated in the source, and highly volatile compounds are released and detected by electron ionization (EI) or chemical ionization (CI).1-3 However, for nonvolatile or thermally labile compounds, this alternative method does not work. Instead, the analyte must be extracted from the TLC stationary phase by an appropriate organic solvent. Previous investigations have successfully detected analytes from the TLC plate by fast-atom bombardment (FAB) and matrix-assisted laser desorption ionization (MALDI) after solvent extraction. 4-8The major concern in FAB/TLC and MALDI/TLC is how to effectively extract the analytes from the TLC stationary phase. Preparing TLC/MALDI samples is complicated because not only must the analytes be extracted from the silica gel, but they must also co-crystallize with the MALDI matrix. 7,8 Recently, Meldal et al. presented a TLC/MALDI method for analyzing organic reaction products. 9 In this method, the analytes are scraped off and extracted from the TLC plate after the components of the reaction mixture have been separated on the TLC plate. The extracted fraction from the TLC plate is then mixed with the MALDI matrix for MALDI analysis. This is an indirect analytical method combining TLC with MALDI. However, this method poses the problem of matrix interference in the low mass range: mos...

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Laser desorption mass spectrometry of nonvolatiles under shock wave conditions

Cited by 107 publications

References 29 publications

Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas

Laser-Induced Acoustic Desorption Atmospheric Pressure Photoionization via VUV-Generating Microplasmas

Laser Desorption Mass Spectrometry. A Review

In situ determination of organic reaction products by combining thin layer chromatography with surface-assisted laser desorption/ionization time-of-flight mass spectrometry

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