UV laser induced molecular multiphoton ionization and fragmentation

Rockwood, S.D.; Reilly, James P.; Hohla, K.; Kompa, K. L.

doi:10.1016/0030-4018(79)90261-x

Cited by 102 publications

(33 citation statements)

References 10 publications

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“…As shown by measurements of photoelectron energies,32 molecules ionize as soon as the sum of absorbed photon energies exceeds the lowest ionization potential. Subsequent absorption by the ion results in extensive fragmentation 33–36. An observed power dependence of the ion peaks confirms that molecular fragmentation of xylene follows the ID mechanism, as suggested by Kosmidis et al in their study of the nitrotoluene isomers 37…”

Section: Discussionsupporting

confidence: 59%

Isomeric identification by laser control mass spectrometry

2006

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The influence shaped femtosecond laser pulses have on molecular photofragmentation and ionization, coupled with the intrinsic sensitivity of mass spectrometry, results in a powerful tool for fast, accurate, reproducible and quantitative isomeric identification. Complex phase functions are introduced to enhance differences during the laser-molecule interactions, which depend on geometric structure, resulting in different fragmentation fingerprints. A full account is given on the setup and results leading to a technique that can be used to distinguish between compounds normally indistinguishable by conventional electron ionization mass spectrometry. We demonstrate geometric and structural isomer identification of cis-/trans-3-heptene, cis-/trans-4-methyl-2-pentene, o-/p-cresol and o-/p-xylene. For the positional isomers of xylene we present a complete dataset consisting of 1024 different phases to explore phase complexity. A selection of two phases from that data can then be used to achieve quantitative identification in mixtures of xylene isomers. Finally, we evaluate receiver operational curves obtained from our experimental data to demonstrate the reliability that can be achieved by femtosecond laser control mass spectrometry.

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Section: Discussionsupporting

confidence: 59%

Isomeric identification by laser control mass spectrometry

2006

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“…Although relative peak heights in each experiment reproduce rather well, the light intensities used to generate the data varied from day to day and from one apparatus to the other. In photoionization mass spectra of small molecules, higher light intensities tend to favor the production of small fragment ions at the expense of larger fragments23 so this operating parameter may be significant. More interestingly, in the ion trap the time between sample irradiation and product ion extraction is on the order of 10 ms, whereas, in the tandem‐TOF apparatus, this time is about 1 μs.…”

Section: Resultsmentioning

confidence: 99%

“…They are observed without the introduction of any analyte and are interpreted as photoionization products associated with organic molecule contaminants in the vacuum system. Laser ionization can readily produce such artifacts 23…”

Section: Resultsmentioning

confidence: 99%

Peptide photodissociation at 157 nm in a linear ion trap mass spectrometer

Kim

Thompson

Reilly

2005

Rapid Comm Mass Spectrometry

118

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The photodissociation by 157 nm light of singly- and doubly-charged peptide ions containing C- or N-terminal arginine residues was studied in a linear ion trap mass spectrometer. Singly-charged peptides yielded primarily x- and a-type ions, depending on the location of the arginine residue, along with some related side-chain fragments. These results are consistent with our previous work using a tandem time-of-flight (TOF) instrument with a vacuum matrix-assisted laser desorption/ionization (MALDI) source. Thus, the different internal energies of precursor ions in the two experiments seem to have little effect on their photofragmentation. For doubly-charged peptides, the dominant fragments observed in both photodissociation and collisionally induced dissociation (CID) experiments are b- and y-type ions. Preliminary experiments demonstrating fragmentation of multiply-charged ubiquitin ions by 157 nm photodissociation are also presented.

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“…As shown by recent measurements of pho toelectron energies (13), the molecule ionizes as soon as the sum of absorbed photon energies exceeds the lowest ionization potential. Subse quent absorption by the ion results in its extensive fragmentation (14)(15)(16)(17), even so far that C+ is often the most prevalent ion produced from the irra diation of benzene. Any fragmentation after the initial ionization does not affect the multi photon ionization spectrum.…”

Section: Introductionmentioning

confidence: 99%