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Fluorometric Beam Profiling of UV MALDI Lasers

  • Rory T. Steven
  • Andrew D. Palmer
  • Josephine Bunch
Research Article

Abstract

The photon distribution (beam profile) of the laser as projected onto the sample is an important variable in matrix assisted laser desorption ionization mass spectrometry (MALDI-MS). Measurement of the beam profile is, therefore, an important factor within MALDI-MS. In this study a simple, low-cost fluorometric laser beam profiling technique is presented and applied in conjunction with MALDI-MS experiments. A comparison of the beam profile information afforded by a commercial system and the fluorometric method is carried out to determine the variation of beam profile for an Nd:YVO4 laser operated between 1 and 25 kHz. The beam profile information can be used, in conjunction with corresponding ion yields, to inform MALDI-MS experiments. The fluorometric beam profiling technique is used to obtain information about the beam dimensions as incident upon the MALDI-MS sample plate in-source. These values are compared with equivalent information obtained from ablation of thin film α-cyano-4-hydroxycinnamic acid (CHCA). In this study, area estimation by ablation provided a value 1.6 times smaller than that obtained by the fluorometric method, demonstrating the need for caution when measuring beam profile and, therefore, fluence, in MALDI-MS.

Key words

Laser beam profiling MALDI-MS UV laser MALDI ionization Fluorescence Laser spot size 

Supplementary material

13361_2013_650_MOESM1_ESM.pdf (406 kb)
ESM 1 (PDF 406 kb)

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Copyright information

© American Society for Mass Spectrometry 2013

Authors and Affiliations

  • Rory T. Steven
    • 1
    • 2
  • Andrew D. Palmer
    • 1
    • 2
    • 3
  • Josephine Bunch
    • 1
    • 2
  1. 1.PSIBS Doctoral Training CentreUniversity of BirminghamBirminghamUK
  2. 2.School of ChemistryUniversity of BirminghamBirminghamUK
  3. 3.School of Computer ScienceUniversity of BirminghamBirminghamUK

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