An automated gas chromatography time-of-flight mass spectrometry instrument for the quantitative analysis of halocarbons in air

  • We present the characterization and application of a new gas chromatography time-of-flight mass spectrometry instrument (GC-TOFMS) for the quantitative analysis of halocarbons in air samples. The setup comprises three fundamental enhancements compared to our earlier work (Hoker et al., 2015): (1) full automation, (2) a mass resolving power R = m/Δm of the TOFMS (Tofwerk AG, Switzerland) increased up to 4000 and (3) a fully accessible data format of the mass spectrometric data. Automation in combination with the accessible data allowed an in-depth characterization of the instrument. Mass accuracy was found to be approximately 5 ppm in mean after automatic recalibration of the mass axis in each measurement. A TOFMS configuration giving R = 3500 was chosen to provide an R-to-sensitivity ratio suitable for our purpose. Calculated detection limits are as low as a few femtograms by means of the accurate mass information. The precision for substance quantification was 0.15 % at the best for an individual measurement and in general mainly determined by the signal-to-noise ratio of the chromatographic peak. Detector non-linearity was found to be insignificant up to a mixing ratio of roughly 150 ppt at 0.5 L sampled volume. At higher concentrations, non-linearities of a few percent were observed (precision level: 0.2 %) but could be attributed to a potential source within the detection system. A straightforward correction for those non-linearities was applied in data processing, again by exploiting the accurate mass information. Based on the overall characterization results, the GC-TOFMS instrument was found to be very well suited for the task of quantitative halocarbon trace gas observation and a big step forward compared to scanning, quadrupole MS with low mass resolving power and a TOFMS technique reported to be non-linear and restricted by a small dynamical range.

Download full text files

Export metadata

Additional Services

Share in Twitter Search Google Scholar
Metadaten
Author:Florian Obersteiner, Harald Bönisch, Andreas EngelORCiD
URN:urn:nbn:de:hebis:30:3-424609
DOI:https://doi.org/10.5194/amt-9-179-2016
ISSN:1867-8548
ISSN:1867-1381
Parent Title (English):Atmospheric measurement techniques
Publisher:Copernicus
Place of publication:Katlenburg-Lindau [u.a.]
Document Type:Article
Language:English
Year of Completion:2016
Date of first Publication:2016/01/25
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2016/12/09
Volume:9
Page Number:16
First Page:179
Last Page:194
Note:
© Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License.
HeBIS-PPN:42476010X
Institutes:Geowissenschaften / Geographie / Geowissenschaften
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 3.0