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Scientific Articles - PTR-MS Bibliography

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Found 9 results
Title [ Year(Asc)]
Filters: Author is Boscaini, Elena  [Clear All Filters]
2004
[Boscaini2004] Boscaini, E., T. Mikoviny, A. Wisthaler, E. von Hartungen, and T. D. Märk, "Characterization of wine with PTR-MS", International Journal of Mass Spectrometry, vol. 239, no. 2: Elsevier, pp. 215–219, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1387380604003537
Abstract
A new method for measuring volatile profiles of alcoholic beverages (or other ethanol-containing analytes such as perfumes or herbs) has been developed. The method is based on proton transfer reaction mass spectrometry (PTR-MS). However, instead of hydronium ions (H3O+) protonated ethanol clusters (C2H5OH2+(C2H5OH)n = 1,2) are used as chemical ionization reagent ions. A stable reagent ion distribution is obtained by a 10-fold dilution of analyte headspace into ethanol-saturated nitrogen. Samples with different ethanol content can thus be directly compared. Characteristic mass spectral fingerprints have been obtained for four wine varieties. Principal component analysis discriminates between different wine varieties and shows specific correlations between wine variety and selected ions.
[Boscaini2004a] Boscaini, E., M. L. Alexander, P. Prazeller, and T. D. Märk, "Investigation of fundamental physical properties of a polydimethylsiloxane (PDMS) membrane using a proton transfer reaction mass spectrometer (PTRMS)", International Journal of Mass Spectrometry, vol. 239, no. 2: Elsevier, pp. 179–186, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1387380604003586
Abstract
A membrane introduction proton transfer reaction mass spectrometer (MI-PTRMS) has been employed for the characterisation of a polydimethylsiloxane (PDMS) membrane. For this purpose the diffusion and partition coefficients (which serve as a measure for solubility) have been determined experimentally for different classes of chemical compounds both non-polar and polar species, i.e., aromatics, alcohols, and ketones. It turned out that not only polar compounds exhibit strong interaction with a hydrophobic membrane such as the PDMS, but also non-polar compounds as trimethylbenzene or propylbenzene show strong interaction with a PDMS membrane. Stronger analyte–membrane interaction leads to a slower diffusion coefficient and larger partition coefficient. The effect of the temperature on the diffusion coefficient and partition coefficient has also been investigated, i.e., at higher temperature diffusion becomes faster and solubility lower. Permeability can be calculated from diffusion and partition coefficients and the activation energy has been derived from corresponding Arrhenius plots. The MI-PTRMS system shows detection limits in the order of tens of pptv and its response is linear for more than four orders of magnitude.
[Boscaini2004b] Boscaini, E., M. L. Alexander, P. Prazeller, and T. D. Märk, "Membrane inlet proton transfer reaction mass spectrometry (MI-PTRMS) for direct measurements of VOCs in water", International Journal of Mass Spectrometry, vol. 239, no. 2: Elsevier, pp. 171–177, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1387380604003896
Abstract
The use of a membrane inlet proton transfer reaction mass spectrometry (MI-PTRMS) system was investigated for the quantitative analysis of VOCs directly from water. Compounds playing an important role in environmental, biological and health issues such as methanol, acetonitrile, acetone, dimethylsulfide (DMS), isoprene, benzene, and toluene have been analyzed both in fresh and salty water. The system shows very good sensitivity, reproducibility, and a linear response of up to five orders of magnitude. The detection limit for DMS is about 100 ppt and for methanol is about 10 ppb both in fresh and salty water. The response time of the various compounds across the membrane is on the order of a few minutes. This fast response and the fact that the PTRMS can perform absolute measurements without the necessity of calibration make the system suitable for on-line and -site measurements of VOCs directly from water.
[Hartungen2004] von Hartungen, E., A. Wisthaler, T. Mikoviny, D. Jaksch, E. Boscaini, P. J. Dunphy, and T. D. Märk, "Proton-transfer-reaction mass spectrometry (PTR-MS) of carboxylic acids: Determination of Henry's law constants and axillary odour investigations", International Journal of Mass Spectrometry, vol. 239, no. 2: Elsevier, pp. 243–248, 2004.
Link: http://www.sciencedirect.com/science/article/pii/S1387380604003902
Abstract
Proton-transfer-reaction mass spectrometry (PTR-MS) was used as an analytical tool to measure gas-phase concentrations of short-chain fatty acids. Chemical ionisation of C2single bondC6 carboxylic acids by PTR-MS produced intense protonated molecular ions (with traces of hydrates) along with acylium ion fragments. Gas-phase concentrations were derived using the established method for calculating PTR-MS sensitivity factors. Henry's law constants of carboxylic acids for aqueous solutions at 40 °C were determined. Direct monitoring of volatile fatty acids, known to be associated with secretions from the human axilla, was performed via a specially designed transfer device situated in the axilla. Mass spectral data corresponded with the findings of a sensory assessor.
2003
[Biasioli2003] Biasioli, F., F. Gasperi, E. Aprea, D. Mott, E. Boscaini, D. Mayr, and T. D. Maerk, "Coupling proton transfer reaction-mass spectrometry with linear discriminant analysis: a case study.", J Agric Food Chem, vol. 51, no. 25: Istituto Agrario di S. Michele a/A, S. Michele, Via E. Mach 2, 38010, Italy. franco.biasioli@ismaa.it, pp. 7227–7233, Dec, 2003.
Link: http://dx.doi.org/10.1021/jf030248i
Abstract
Proton transfer reaction-mass spectrometry (PTR-MS) measurements on single intact strawberry fruits were combined with an appropriate data analysis based on compression of spectrometric data followed by class modeling. In a first experiment 8 of 9 different strawberry varieties measured on the third to fourth day after harvest could be successfully distinguished by linear discriminant analysis (LDA) on PTR-MS spectra compressed by discriminant partial least squares (dPLS). In a second experiment two varieties were investigated as to whether different growing conditions (open field, tunnel), location, and/or harvesting time can affect the proposed classification method. Internal cross-validation gives 27 successes of 28 tests for the 9 varieties experiment and 100% for the 2 clones experiment (30 samples). For one clone, present in both experiments, the models developed for one experiment were successfully tested with the homogeneous independent data of the other with success rates of 100% (3 of 3) and 93% (14 of 15), respectively. This is an indication that the proposed combination of PTR-MS with discriminant analysis and class modeling provides a new and valuable tool for product classification in agroindustrial applications.
[Boscaini2003] Boscaini, E., S. { van Ruth}, F. Biasioli, F. Gasperi, and T. D. Maerk, "Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of grana padano, parmigiano reggiano, and grana trentino cheeses.", J Agric Food Chem, vol. 51, no. 7: Institut fuer Ionenphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria., pp. 1782–1790, Mar, 2003.
Link: http://dx.doi.org/10.1021/jf020922g
Abstract
Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample.
[Alexander2003] Alexander, M., E. Boscaini, W. Lindinger, and T. D. Märk, "Membrane introduction proton-transfer reaction mass spectrometry", International Journal of Mass Spectrometry, vol. 223: Elsevier, pp. 763–770, 2003.
Link: http://www.sciencedirect.com/science/article/pii/S1387380602009648
Abstract
The combination of membrane introduction mass spectrometry (MIMS) and proton-transfer reaction mass spectrometry (PTR-MS) is explored. The PTR-MS is used to measure properties of a well-characterized membrane material, poly-dimethylsiloxane (PDMS). It is found that the ability of the PTR-MS to measure absolute concentrations in real-time makes it an ideal tool for the characterization of membrane properties and the interaction of the membrane with multiple organic species. Values for the diffusion coefficients of several molecules are measured and found to be in agreement with literature values. Time modulation of the analyte across the membrane is explored as a method of resolving isobaric interferences for different chemical species. This is demonstrated for acetone and propanal. Finally, the benefit of combining MIMS with PTR-MS is demonstrated by the direct analysis of organic species in the headspace of a hot water solution where the high humidity would not allow analysis using the PTR-MS alone.
[Prazeller2003] Prazeller, P., P. T. Palmer, E. Boscaini, T. Jobson, and M. Alexander, "Proton transfer reaction ion trap mass spectrometer", Rapid communications in mass spectrometry, vol. 17, no. 14: Wiley Online Library, pp. 1593–1599, 2003.
Link: http://onlinelibrary.wiley.com/doi/10.1002/rcm.1088/full
Abstract
Proton transfer reaction mass spectrometry is a relatively new field that has attracted a great deal of interest in the last few years. This technique uses H3O+ as a chemical ionization (CI) reagent to measure volatile organic compounds (VOCs) in the parts per billion by volume (ppbv) to parts per trillion by volume (pptv) range. Mass spectra acquired with a proton transfer reaction mass spectrometer (PTR-MS) are simple because proton transfer chemical ionization is ‘soft’ and results in little or no fragmentation. Unfortunately, peak identification can still be difficult due to isobaric interferences. A possible solution to this problem is to couple the PTR drift tube to an ion trap mass spectrometer (ITMS). The use of an ITMS is appealing because of its ability to perform MS/MS and possibly distinguish between isomers and other isobars. Additionally, the ITMS duty cycle is much higher than that of a linear quadrupole so faster data acquisition rates are possible that will allow for detection of multiple compounds. Here we present the first results from a proton transfer reaction ion trap mass spectrometer (PTR-ITMS). The aim of this study was to investigate ion injection and storage efficiency of a simple prototype instrument in order to estimate possible detection limits of a second-generation instrument. Using this prototype a detection limit of 100 ppbv was demonstrated. Modifications are suggested that will enable further reduction in detection limits to the low-ppbv to high-pptv range. Furthermore, the applicability of MS/MS in differentiating between isobaric species was determined. MS/MS spectra of the isobaric compounds methyl vinyl ketone (MVK) and methacrolein (MACR) are presented and show fragments of different mass making differentiation possible, even when a mixture of both species is present in the same sample. However, MS/MS spectra of acetone and propanal produce fragments with the same molecular masses but with different intensity ratios. This allows quantitative distinction only if one species is predominant. Fragmentation mechanisms are proposed to explain the results.
2001
[Gasperi2001] Gasperi, F., G. Gallerani, A. Boschetti, F. Biasioli, A. Monetti, E. Boscaini, A. Jordan, W. Lindinger, and S. Iannotta, "The mozzarella cheese flavour profile: a comparison between judge panel analysis and proton transfer reaction mass spectrometry", Journal of the Science of Food and Agriculture, vol. 81, no. 3: Wiley Online Library, pp. 357–363, 2001.
Link: http://onlinelibrary.wiley.com/doi/10.1002/1097-0010(200102)81:3%3C357::AID-JSFA818%3E3.0.CO;2-O/full

Featured Articles

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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).
Link

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.
Link

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.
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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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