Berlin 2001 – scientific programme

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MS: Massenspektrometrie

MS 6: Clusters, Molecules, Laser Desorption and MALDI

MS 6.3: Talk

Thursday, April 5, 2001, 16:45–17:00, EB 202

Photoacoustic Analysis of the Desorption Process in IR-MALDI-MS — •A. Rohlfing, C. Menzel, F. Hillenkamp, and K. Dreisewerd — Institut für Medizinische Physik & Biophysik, Westfälische Wilhelms-Universität, Robert-Koch-Str. 31, D-48149 Münster

Despite the growing importance as an analytical method [1] the physical mechanisms underlying the IR-MALDI process are still only partly understood. According to the so-called spallation model [2] the desorption process would be based upon the build-up of high-amplitude tensile stress waves caused by the rapid heating of the sample and tearing the sample apart. The detection of such photoacoustic waves and analysis of the superimposed compressive recoil momentum signals caused by material ablation therefore is a promising approach to obtain a better undestanding for the MALDI process.

In order to detect photoacoustic stress waves and ion signals simultaneously a piezoelectric transducer was mounted into a modified high-voltage proof MALDI target and spectra recorded with a home-built IR-MALDI-TOF mass spectrometer. Standard MALDI preparations of substance P in glycerol were used as test samples. The procedures of signal detection and analysis as well as first results, suggesting a correlation of ion and recoil momentum signal intensities, will be reported.

[1] Overberg et al., Rapid Commun. Mass Spectrom., 4 (1990) 293-296.

[2] Dingus & Scammon in No-dqMiller, Haglund: Laser Ablation:

Mechanisms and ApplicationsNo-dq, Springer, Berlin, 1991, 180-190.