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Scientific Articles - PTR-MS Bibliography

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Found 3 results
Title [ Year(Asc)]
Filters: Author is Andrea Romano  [Clear All Filters]
[1847] Romano, A., and G. B. Hanna, "Identification and quantification of {VOCs} by Proton Transfer Reaction Time of Flight Mass Spectrometry: an experimental workflow for the optimization of specificity, sensitivity and accuracy.", Journal of Mass Spectrometry, jan, 2018.
<p>Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF-MS) is a direct injection MS technique, allowing for the sensitive and real-time detection, identification and quantification of volatile organic compounds (VOCs). When aiming to employ PTR-ToF-MS for targeted VOC analysis some methodological questions must be addressed, such as the need to correctly identify product ions, or evaluating the quantitation accuracy. This work proposes a workflow for PTR-ToF-MS method development, addressing the main issues affecting the reliable identification and quantification of target compounds. We determined the fragmentation patterns of 13 selected compounds (aldehydes, fatty acids, phenols). Experiments were conducted under breath-relevant conditions (100% humid air), and within an extended range of reduced electric field values (E/N = 48-144 Td), obtained by changing drift tube voltage. Reactivity was inspected using H3O+, NO+ and O2+ as primary ions. The results show that a relatively low (&lt; 90 Td) E/N often permits to reduce fragmentation enhancing sensitivity and identification capabilities, particularly in the case of aldehydes using NO+, where a 4-fold increase in sensitivity is obtained by means of drift voltage reduction. We developed a novel calibration methodology, relying on diffusion tubes used as gravimetric standards. For each of the tested compounds, it was possible to define suitable conditions whereby experimental error, defined as difference between gravimetric measurements and calculated concentrations, was 8% or lower.</p>
[1839] Doran, S., A. Romano, and G. B. Hanna, "Optimization of sampling parameters for standardized exhaled breath sampling", Journal of Breath Research, sep, 2017.
The lack of standardization of breath sampling is a major contributing factor to the poor repeatability of results and hence represents a barrier to the adoption of breath tests in clinical practice. On-line and bag breath sampling have advantages but do not suit multicentre clinical studies whereas storage and robust transport are essential for the conduct of wide-scale studies. Several devices have been developed to control sampling parameters and to concentrate volatile organic compounds (VOCs) onto thermal desorption (TD) tubes and subsequently transport those tubes for laboratory analysis. &#13; We conducted three experiments to investigate (i) the fraction of breath sampled (whole vs. lower expiratory exhaled breath); (ii) breath sample volume (125, 250, 500 and 1000ml) and (iii) breath sample flow rate (400, 200, 100 and 50 ml/min). The target VOCs were acetone and potential volatile biomarkers for oesophago-gastric cancer belonging to the aldehyde, fatty acids and phenol chemical classes. We also examined the collection execution time and the impact of environmental contamination.&#13; The experiments showed that the use of exhaled breath-sampling devices requires the selection of optimum sampling parameters. The increase in sample volume has improved the levels of VOCs detected. However, the influence of the fraction of exhaled breath and the flow rate depends on the target VOCs measured. The concentration of potential volatile biomarkers for oesophago-gastric cancer was not significantly different between the whole and lower airway exhaled breath. While the recovery of phenols and acetone from TD tubes was lower when breath sampling was performed at a higher flow rate, other VOCs were not affected. A dedicated 'clean air supply' overcomes the contamination from ambient air, but the breath collection device itself can be a source of contaminants. In clinical studies using VOCs to diagnose gastro-oesophageal cancer, the optimum parameters are 500mls sample volume of whole breath with a flow rate of 200ml/min. &#13;
[1546] Romano, A., L. Fischer, J. Herbig, H. Campbell-Sills, J. Coulon, P. Lucas, L. Cappellin, and F. Biasioli, "Wine analysis by FastGC proton-transfer reaction-time-of-flight-mass spectrometry", International Journal of Mass Spectrometry, vol. 369, pp. 81 - 86, 2014.
<p>Abstract Proton transfer reaction-mass spectrometry (PTR-MS) has successfully been applied to a wide variety of food matrices, nevertheless the reports about the use of PTR-MS in the analysis of alcoholic beverages remain anecdotal. Indeed, due to the presence of ethanol in the sample, PTR-MS can only be employed after dilution of the headspace or at the expense of radical changes in the operational conditions. In the present research work, PTR-ToF-MS was coupled to a prototype FastGC system allowing for a rapid (90&nbsp;s) chromatographic separation of the sample headspace prior to PTR-MS analysis. The system was tested on red wine: the FastGC step allowed to rule out the effect of ethanol, eluted from the column during the first 8&nbsp;s, allowing PTR-MS analysis to be carried out without changing the ionization conditions. Eight French red wines were submitted to analysis and could be separated on the basis of the respective grape variety and region of origin. In comparison to the results obtained by direct injection, FastGC provided additional information, thanks to a less drastic dilution of the sample and due to the chromatographic separation of isomers. This was achieved without increasing duration and complexity of the analysis.</p>

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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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