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MS: Massenspektrometrie
MS 6: Clusters, Molecules, Laser Desorption and MALDI
MS 6.4: Vortrag
Donnerstag, 5. April 2001, 17:00–17:15, EB 202
Matrix-Free Infrared Laser Desorption and Ionization Time-of-Flight Mass Spectrometry for Bacterial Identification — •Matthias Frank1, Joel N. Ullom1, Eric E. Gard1, Kevin C. Langry1, Frank Magnotta1, Sharon J. Shields1, Joanne M. Horn1, Simon E. Labov1, Fred P. Milanovich1, Christopher A. Hack2 und W. Henry Benner2 — 1Lawrence Livermore National Laboratory, Livermore CA 94551 — 2Lawrence Berkeley National Laboratroy, Berkeley, CA 94720
We present results from demonstration experiments showing that molecular ions ranging in mass from a few hundred Da to 19 kDa can be desorbed from whole bacterial spores using infrared laser desorption and no chemical matrix. Using a tunable IR laser based on a Nd:YAG-pumped optical paramtric oscillator we have measured the dependence of the ion yield from Bacillus subtilis on desorption wavelength over the range 3.05-3.8 micrometers and we observe the best results at 3.05 micrometers. Measuring the mass of these ions using time-of-flight mass spectrometry revealed that different ions are desorbed from spores of B.cereus, B. thuringiensis, B. subtilis, and B. niger. This indicates that identifying microorganisms using mass spectrometry without conventional sample preparation techniques such as the addition of a matrix should be possible. We also describe our ongoing efforts to improve the sensitivity of this method by increasing the ion yield with a second laser.