Regensburg 2007 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 18: Neuartige Messverfahren der Umweltphysik

UP 18.2: Vortrag

Mittwoch, 28. März 2007, 17:15–17:30, H48

Performance Assessment of a Recently Developed High Resolution PTR-TOFMS Instrument — •Markus Müller, Martin Graus, Armin Wisthaler, and Armin Hansel — Institute of Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, AUSTRIA

A High Resolution Proton Transfer Reaction Time-of-Flight Mass Spectrometer (HR-PTR-TOFMS) was recently developed at the University of Innsbruck. The HR-PTR-TOFMS is a powerful new analytical tool for on-line analysis of volatile organic compounds. The conventional PTR-MS instrument uses a quadrupole mass spectrometer (QMS) for ion separation and ion detection. The QMS keeps peak widths almost constant to 1 mass unit. Isobaric ions, i.e. ions that have the same nominal mass but a different exact mass, cannot be separated. The Innsbruck HR-PTR-TOFMS has a mass resolving power of approximatly 4000 (FWHM) and is thus capable of distinguishing between a variety of isobaric ions. This is not only a great advantage for the identification of trace gases in complex sample matrices but can also significantly improve the detection limit in cases where the background signal is isobaric and thus separated in the HR-PTR-TOFMS. Detection limits as low as 20pptv were obtained for a one minute integration period. Another advantage for ion detection with a TOF-MS is the high duty cycle which leads to total mass spectrum within one second integration time. The HR-PTR-TOFMS Instrument and its performance characteristics will be discussed and compared to the characteristics of a standard PTR-MS instrument.