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Scientific Articles - PTR-MS Bibliography

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Found 3 results
Title [ Year(Asc)]
Filters: Author is Demarcke, M  [Clear All Filters]
[Simpraga2013] Šimpraga, M., H. Verbeeck, J. Bloemen, L. Vanhaecke, M. Demarcke, E. Joó, O. Pokorska, C. Amelynck, N. Schoon, J. Dewulf, et al., "Vertical canopy gradient in photosynthesis and monoterpenoid emissions: An insight into the chemistry and physiology behind", Atmospheric Environment: Elsevier, 2013.
It is well known that vertical canopy gradients and varying sky conditions influence photosynthesis (Pn), specific leaf area (SLA), leaf thickness (LT) and leaf pigments (lutein, â-carotene and chlorophyll). In contrast, little is known about these effects on monoterpenoid (MT) emissions. Our study examines simultaneously measured Pn, MT emissions and the MT/Pn ratio along the canopy of an adult European beech tree (Fagus sylvatica L.) in natural forest conditions. Dynamic branch enclosure systems were used at four heights in the canopy (7, 14, 21 and 25 m) in order to establish relationships and better understand the interaction between Pn and MT emissions under both sunny and cloudy sky conditions. Clear differences in Pn, MT emissions and the MT/Pn ratio were detected within the canopy. The highest Pn rates were observed in the sun leaves at 25 m due to the higher intercepted light levels, whereas MT emissions (and the MT/Pn ratio) were unexpectedly highest in the semi-shaded leaves at 21 m. The higher Pn rates and, apparently contradictory, lower MT emissions in the sun leaves may be explained by the hypothesis of Owen and Peñuelas (2005), stating synthesis of more photo-protective carotenoids may decrease the emissions of volatile isoprenoids (including MTs) because they both share the same biochemical precursors. In addition, leaf traits like SLA, LT and leaf pigments clearly differed with height in the canopy, suggesting that the leaf's physiological status cannot be neglected in future research on biogenic volatile organic compounds (BVOCs) when aiming at developing new and/or improved emission algorithms.
[Joo2010a] Joó, É., J. Dewulf, M. Demarcke, C. Amelynck, N. Schoon, J-F. Müller, M. Šimpraga, K. Steppe, and H. Van Langenhove, "Quantification of interferences in PTR-MS measurements of monoterpene emissions from Fagus sylvatica L. using simultaneous TD-GC-MS measurements", International Journal of Mass Spectrometry, vol. 291, no. 1: Elsevier, pp. 90–95, 2010.
The interest in quantitative analysis of biogenic volatile organic compounds (BVOCs) emissions stems from their importance in atmospheric chemistry. In order to compare the most frequently used BVOC measurement techniques, simultaneous on-line PTR-MS and off-line GC-MS data collection was performed on a 3 years old Fagus sylvatica L. tree placed in a growth chamber. Using an internal standard (deuterated toluene) and applying the selective ion mode (SIM) resulted in significant improvements of monoterpene (MT) quantification by TD-GC-MS. PTR-MS quantification of MTs was based on the ion signal at m/z 137. In the course of the experiments the relative contribution of linalool compared to that of MTs was found to be up to 84%. Since this compound has also a PTR-MS signature at m/z 137, quantification of MT emission rates by PTR-MS was disturbed. Comparison of GC-MS and PTR-MS data allowed an estimation of the ratio of the PTR-MS sensitivity for linalool to the one for MTs at m/z 137. This ratio of sensitivities, combined with the information of the relative contribution of linalool to the sum of linalool and MTs obtained by GC-MS, resulted in accurate derivation of the sum of emission rates of linalool and MTs by PTR-MS. The results indicate that fast and on-line PTR-MS measurements of BVOCs are best accompanied by off-line GC measurements to detect possible interferences or to use the additional information for properly quantifying the sum of emission rates of several compounds.
[Demarcke2009] Demarcke, M., C. Amelynck, N. Schoon, F. Dhooghe, H. Van Langenhove, and J. Dewulf, "Laboratory studies in support of the detection of sesquiterpenes by proton-transfer-reaction-mass-spectrometry", International Journal of Mass Spectrometry, vol. 279, no. 2: Elsevier, pp. 156–162, 2009.
The effects of the ratio of the electric field strength to the buffer gas number density (E/N) in the drift tube of a proton transfer reaction mass spectrometer on the product ion distributions of the sesquiterpenes β-caryophyllene, α-humulene, α-cedrene and longifolene have been investigated.Chemical ionization of the sesquiterpenes resulted in important fragmentation of the nascent excited ion/molecule complex at the highest E/N values. The most important fragment ions were common to all sesquiterpenes and therefore cannot be used as fingerprints for specific isomers. The yield of the protonated molecule increased on average by a factor 1.6 by decreasing E/N from 140 to 80 Td. Taking into account the influence of E/N on the reaction time and on the reactant ion mobility, it is estimated that this decrease in E/N may lead to an overall increase in the PTR-MS detection sensitivity of sesquiterpenes (based on the ion signal at m/z 205) by a factor 3.5.Product ion distributions of α-cedrene and longifolene have also been determined at different water vapour pressures. No substantial influence of the water vapour pressure on the product ion yields was observed, which is an advantage when quantifying sesquiterpenes by PTR-MS in samples of varying relative humidity.

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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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