Osnabrück 2002 – wissenschaftliches Programm

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MS: Massenspektrometrie

MS 6: Massenspektrometrie an Atmosphäre und Aerosolen, Ionisationsmethoden

MS 6.2: Vortrag

Donnerstag, 7. März 2002, 18:00–18:15, HS 02/E04

Delayed Ion Extraction For Single-particle Bipolar On-line Laser Mass Spectrometry — •Cesar Costa Vera, Achim Trimborn, Klaus-Peter Hinz, and Bernhard Spengler — Universiy of Giessen, Schubertstr. 60, D-35392,Giessen

The principle of bipolar on-line laser mass spectrometry of aerosols has been realized with a linear TOF instruments, LAMPAS 2.[1] With this method general chemical properties of single airborne particles can be determined by simultaneously recording negative and positive ion spectra, as well as the aerodynamical diameter of aerosol particles. Delayed ion extraction can be used to improve mass resolution in such instrument provided some physical and instrumental conditions apply. One of such prerequisites is that the initial velocity spread effect across the ion packet extension is sufficiently stronger than that of the spatial spread. On the other hand, the information obtained by using delayed extraction can be used complementary, to shed light on the physical mechanisms by which ion generation occurs, for both ion polarities. For instance, an instantaneous complete particle ablation would produce ions over volumes comparable to the original particle size, and with widely distributed initial speeds.

We will report results of our attempts to use DE in the LAMPAS 2 instrument to improve mass resolution and discuss their physical and instrumental implications.

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