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Scientific Articles - PTR-MS Bibliography

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Found 6 results
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Filters: Author is Maerk, TD  [Clear All Filters]
[Mayhew2010] Mayhew, CA., P. Sulzer, F. Petersson, S. Haidacher, A. Jordan, L. Maerk, P. Watts, and TD. Maerk, "Applications of proton transfer reaction time-of-flight mass spectrometry for the sensitive and rapid real-time detection of solid high explosives", International Journal of Mass Spectrometry, vol. 289, no. 1: Elsevier, pp. 58–63, 2010.
Using recent developments in proton transfer reaction mass spectrometry, proof-of-principle investigations are reported here to illustrate the capabilities of detecting solid explosives in real-time. Two proton transfer reaction time-of-flight mass spectrometers (Ionicon Analytik) have been used in this study. One has an enhanced mass resolution (m/Δm up to 8000) and high sensitivity (∼50 cps/ppbv). The second has enhanced sensitivity (∼250 cps/ppbv) whilst still retaining high resolution capabilities (m/Δm up to 2000). Both of these instruments have been successfully used to identify solid explosives (RDX, TNT, HMX, PETN and Semtex A) by analyzing the headspace above small quantities of samples at room temperature and from trace quantities not visible to the naked eye placed on surfaces. For the trace measurements a simple pre-concentration and thermal desorption technique was devised and used. Importantly, we demonstrate the unambiguous identification of threat agents in complex chemical environments, where multiple threat agents and interferents may be present, thereby eliminating false positives. This is of considerable benefit to security and for the fight against terrorism.
[Jordan2009a] Jordan, A., S. Haidacher, G. Hanel, E. Hartungen, L. Maerk, H. Seehauser, R. Schottkowsky, P. Sulzer, and TD. Maerk, "A Commercial High-Resolution, High-Sensitivity (HRS) PTR-TOF-MS Instrument", CONFERENCE SERIES, pp. 239, 2009.
[Jordan2009b] Jordan, A., S. Haidacher, G. Hanel, E. Hartungen, L. Maerk, H. Seehauser, R. Schottkowsky, P. Sulzer, and TD. Maerk, "A high resolution and high sensitivity proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS)", International Journal of Mass Spectrometry, vol. 286, no. 2: Elsevier, pp. 122–128, 2009.
Proton-transfer-reaction mass spectrometry (PTR-MS) developed about 10 years ago is used today in a wide range of scientific and technical fields allowing real-time on-line measurements of volatile organic compounds in air with a high sensitivity and a fast response time. Most instruments employed so far use quadrupole filters to analyze product ions generated in the reaction drift tube. Due to the low mass resolution of the quadrupoles used this has the disadvantage that identification of trace gases under study is not unambiguous. Here we report the development of a new version of PTR-MS instruments using a time-of-flight mass spectrometer, which is capable of measuring VOCs at ultra-low concentrations (as low as a few pptv) under high mass resolution (as high as 6000 m/Δm in the V-mode) with a mass range of beyond 100 000 amu. This instrument was constructed by interfacing the well characterized and recently improved Ionicon hollow cathode ion source and drift tube section with a Tofwerk orthogonal acceleration reflectron time-of-flight mass spectrometer. We will first discuss the set-up of this new PTR-TOF-MS mass spectrometer instrument, its performance (with a sensitivity of several tens of cps/ppbv) and finally give some examples concerning urban air measurements where sensitivity, detection limit and mass resolution is essential to obtain relevant data.
[Jordan2009c] Jordan, A., S. Haidacher, G. Hanel, E. Hartungen, J. Herbig, L. Maerk, R. Schottkowsky, H. Seehauser, P. Sulzer, and TD. Maerk, "An online ultra-high sensitivity Proton-transfer-reaction mass-spectrometer combined with switchable reagent ion capability (PTR+ SRI- MS)", International Journal of Mass Spectrometry, vol. 286, no. 1: Elsevier, pp. 32–38, 2009.
Proton-transfer-reaction mass-spectrometry (PTR-MS) developed in the 1990s is used today in a wide range of scientific and technical fields. PTR-MS allows for real-time, online determination of absolute concentrations of volatile (organic) compounds (VOCs) in air with high sensitivity (into the low pptv range) and a fast response time (in the 40–100 ms time regime). Most PTR-MS instruments employed so far use an ion source consisting of a hollow cathode (HC) discharge in water vapour which provides an intense source of proton donor H3O+ ions. As the use of other ions, e.g. NO+ and O2+, can be useful for the identification of VOCs and for the detection of VOCs with proton affinities (PA) below that of H2O, selected ion flow tube mass spectrometry (SIFT-MS) with mass selected ions has been applied in these instances. SIFT-MS suffers, however, from at least two orders lower reagent ion counts rates and therefore SIFT-MS suffers from lower sensitivity than PTR-MS. Here we report the development of a PTR-MS instrument using a modified HC ion source and drift tube design, which allows for the easy and fast switching between H3O+, NO+ and O2+ ions produced in high purity and in large quantities in this source. This instrument is capable of measuring low concentrations (with detection limits approaching the ppqv regime) of VOCs using any of the three reagent ions investigated in this study. Therefore this instrument combines the advantages of the PTR-MS technology (the superior sensitivity) with those of SIFT-MS (detection of VOCs with PAs smaller than that of the water molecule and the capability to distinguish between isomeric compounds). We will first discuss the setup of this new PTR+SRI-MS mass spectrometer instrument, its performance for aromates, aldehydes and ketones (with a sensitivity of up to nearly 1000 cps/ppbv and a detection limit of about several 100 ppqv) and finally give some examples concerning the ability to distinguish structural isomeric compounds.
[Biasioli2004b] Biasioli, F., F. Gasperi, D. Mott, E. Aprea, F. Marini, and TD. Maerk, "Characterization of Strawberry Genotypes by PTR-MS Spectral Fingerprinting: a Three Year Study", V International Strawberry Symposium 708, pp. 497–500, 2004.
Proton Transfer Reaction Mass Spectrometry (PTR-MS) fingerprinting has been used to accurately and rapidly identify the cultivar of single intact strawberry fruits. The technique has been applied in a 3-cultivar experiment with 70 fruits harvested in 2002, 2003 and 2004. The proposed models correctly predicted the cultivar. Cross-validation tests verified 100% correct classification. The data indicated the possibility of correctly characterizing single fruit by fast non-invasive measurements without any pre-treatment and/or concentration of the headspace gas mixture. This is a necessary preliminary step in view of correlation studies of PTR-MS data with genetics and other characterization of fruits, in particular, sensory analysis. Extension to more cultivars is envisaged.
[Biasioli2003a] Biasioli, F., F. Gasperi, E. Aprea, L. Colato, E. Boscaini, and TD. Maerk, "Fingerprinting mass spectrometry by PTR-MS: heat treatment vs. pressure treatment of red orange juice - a case study", International journal of mass spectrometry, vol. 223: Elsevier, pp. 343–353, 2003.
Proton transfer reaction mass spectrometry (PTR-MS) is more and more applied to rather different fields of research and applications showing interesting performances where high sensitivity and fast monitoring of volatile organic compounds (VOCs) are required. Based on this technique and aiming at the realisation of an automatic system for routine applications in food science and technology, we tested here a novel approach for fingerprinting mass spectrometric detection and analysis of complex mixtures of VOCs. In particular, we describe and discuss corresponding head space (HS) sampling methods and possible data analysis techniques. As a first test case we studied here the properties of four red orange juices processed by different stabilisation methods starting from the same industrial batch: untreated juice, thermal pasteurised (flash and standard) juice and high pressure stabilised juice. We demonstrate the possibility of a fast automatic discrimination/classification of the samples with the further advantage, compared to the use of electronic noses, of useful information on the mass of the discriminating compounds. Moreover, first comparisons with discriminative analysis by a sensory panel shows evidence that there is a correlation between the ability of the PTR-MS to distinguish different juice samples and that of a panel of trained judges with the obvious advantages of an instrumental approach.

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Selected PTR-MS related Reviews

F. Biasioli, C. Yeretzian, F. Gasperi, T. D. Märk: PTR-MS monitoring of VOCs and BVOCs in food science and technology, Trends in Analytical Chemistry 30 (7) (2011).

J. de Gouw, C. Warneke, T. Karl, G. Eerdekens, C. van der Veen, R. Fall: Measurement of Volatile Organic Compounds in the Earth's Atmosphere using Proton-Transfer-Reaction Mass Spectrometry. Mass Spectrometry Reviews, 26 (2007), 223-257.

W. Lindinger, A. Hansel, A. Jordan: Proton-transfer-reaction mass spectrometry (PTR–MS): on-line monitoring of volatile organic compounds at pptv levels, Chem. Soc. Rev. 27 (1998), 347-375.


Lists with PTR-MS relevant publications of the University of Innsbruck can be found here: Atmospheric and indoor air chemistry, IMR, Environmental Physics and Nano-Bio-Physics


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