Hannover 2003 – wissenschaftliches Programm

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MS: Massenspektrometrie

MS 5: Massenspektrometr. Verfahren und Entwicklungen

MS 5.4: Vortrag

Donnerstag, 27. März 2003, 17:15–17:30, F 428

Initial velocity studies with simultaneous positive and negative delayed extraction of ions produced by in-flight LDI of non-impacted aerosol particles — •Cesar Costa Vera, Achim Trimborn, Klaus-Peter Hinz, and Bernhard Spengler — Justus-Liebig-Uni. Giessen, Inst. of Inorg. and Analyt. Chem., Schubertstr. 60, D-35392, Giessen

Delayed ion extraction (DE) has been implemented in a LDI TOF mass spectrometer for bipolar on-line analysis of aerosols (LAMPAS 2), for both ion polarities. [1, 2] The parameters of DE (extraction voltage and delay), give valuable information about the initial velocities of the ions. We described before the spectral characteristics related to DE of the positive ions from LATEX aerosols obtained in DE experiments.[2]. It was suggested that, under our conditions, a full evaporation of aerosol particles does not occur, and that the ions expand against the incoming ablating laser beam. We also found systematic differences in the behaviour of different hydrocarbon-related ionic clusters: Cn+, CnHm+.

We will present results for the negative ions, and discuss the experimental data, in the context of the dynamics of the expansion of the ion cloud produced by LDI from non-impacted aerosols.

[1] A. Trimborn, K.-P. Hinz, and B. Spengler, Aeros. Sci. Tech. 33 (2000) 191

[2] C. Costa Vera, A. Trimborn, K.-P. Hinz, and B. Spengler, Desorption 2002, Estes Park, CO, USA, Sept. 1-5, 2002