The Experts below are selected from a list of 259251 Experts worldwide ranked by ideXlab platform
Werner Lindinger - One of the best experts on this subject based on the ideXlab platform.
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breath by breath analysis of banana aroma by proton transfer Reaction Mass spectrometry
International Journal of Mass Spectrometry, 2003Co-Authors: D Mayr, Hugues Brevard, Werner Lindinger, T D Mark, Chahan YeretzianAbstract:We report on the in vivo breath-by-breath analysis of volatiles released in the mouth during eating of ripe and unripe banana. The air exhaled through the nose, nosespace (NS), is directly introduced into a proton transfer Reaction Mass spectrometer and the time-intensity profiles of a series of volatiles are monitored on-line. These include isopentyl and isobutyl acetate, two characteristic odour compounds of ripe banana, and 2E-hexenal and hexanal, compounds typical of unripe banana. Comparing the NS with the headspace (HS) profile, two differences are outlined. First, NS concentrations of some compounds are increased, compared to the HS, while others are decreased. This indicates that the in-mouth situation has characteristics of its own—mastication, mixing/dilution with saliva, temperature and pH—which modify the aroma relative to an HS aroma. Second, we discuss the temporal evolution of the NS. While 2E-hexenal and hexanal steadily increase in the NS during mastication of unripe banana, no such evolution is observed in volatile organic compounds (VOCs) while eating ripe banana. Furthermore, ripe banana shows high VOC concentrations in the swallow breath in contrast to unripe banana.
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reath by breath analysis of banana aroma by proton transfer Reaction Mass spectrometry
Journal of Mass Spectrometry, 2003Co-Authors: D Mayr, Tilmann Maerk, Hugues Brevard, Werner Lindinger, Chahan YeretzianAbstract:We report on the in vivo breath-by-breath analysis of volatiles released in the mouth during eating of ripe and unripe banana. The air exhaled through the nose, nosespace (NS), is directly introduced into a proton transfer Reaction Mass spectrometer and the time-intensity profiles of a series of volatiles are monitored on-line. These include isopentyl and isobutyl acetate, two characteristic odour compounds of ripe banana, and 2E-hexenal and hexanal, compounds typical of unripe banana. Comparing the NS with the headspace (HS) profile, two differences are outlined. First, NS concentrations of some compounds are increased, compared to the HS, while others are decreased. This indicates that the in-mouth situation has characteristics of its own—mastication, mixing/dilution with saliva, temperature and pH—which modify the aroma relative to an HS aroma. Second, we discuss the temporal evolution of the NS. While 2E-hexenal and hexanal steadily increase in the NS during mastication of unripe banana, no such evolution is observed in volatile organic compounds (VOCs) while eating ripe banana. Furthermore, ripe banana shows high VOC concentrations in the swallow breath in contrast to unripe banana. (Int J Mass Spectrom 223–224 (2003) 743–756) © 2002 Elsevier Science B.V. All rights reserved.
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trace gas monitoring at the mauna loa baseline observatory using proton transfer Reaction Mass spectrometry
International Journal of Mass Spectrometry, 2003Co-Authors: T Karl, Werner Lindinger, Armin Hansel, T D Mark, David HoffmannAbstract:Real time monitoring of volatile organic compounds (VOCs) using a Proton-Transfer Reaction Mass Spectrometer was performed at the Mauna Loa Baseline Station (19.54N, 155.58W) in March/April 2001 (March 23, 2001–April 17, 2001). Mixing ratios for methanol, acetone, acetonitrile, isoprene and methyl vinyl ketone (MVK) plus methacrolein (MACR) ranged between 0.2 and 1.8, 0.2 and 1, 0.07 and 0.2, <0.02 and 0.3, and <0.02 and 0.5 ppbv, respectively. BioMass burning plumes transported from South-East Asia and the Indian Subcontinent across the Pacific influenced part of the measurement campaign.
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Membrane introduction proton-transfer Reaction Mass spectrometry
International Journal of Mass Spectrometry, 2002Co-Authors: Michael L. Alexander, Werner Lindinger, E. Boscaini, Tilmann D. MärkAbstract: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.
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Dynamic measurements of partition coefficients using proton-transfer-Reaction Mass spectrometry (PTR–MS)
International Journal of Mass Spectrometry, 2002Co-Authors: Thomas Karl, Chahan Yeretzian, Alfons Jordan, Werner LindingerAbstract:Abstract Liquid–gas partition coefficients (HLC) of volatile organic compounds (VOCs) in water–air systems are determined using a novel dynamic approach by coupling a stripping cell directly to a proton-transfer-Reaction Mass spectrometer (PTR–MS). Two complementary set-ups are evaluated, one suited for determining HLCs of highly volatile compounds (
Yannan Chu - One of the best experts on this subject based on the ideXlab platform.
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Imaging VOC distribution in cities and tracing VOC emission sources with a novel mobile proton transfer Reaction Mass spectrometer.
Environmental Pollution, 2020Co-Authors: Qu Liang, Chengyin Shen, Huang Chaoqun, Qiangling Zhang, Xue Zou, Xun Bao, Qin Sun, Yannan ChuAbstract:Abstract Volatile organic compounds (VOCs) are important precursors of ozone (O3) and secondary organic aerosols (SOAs). Tracing VOC pollution sources is important for controlling VOC emissions and reducing O3 and SOAs. We built a novel mobile proton transfer Reaction Mass spectrometry (M-PTR-MS) instrument to image the distribution of VOCs and trace their emission sources in cities and industrial parks. The M-PTR-MS is composed of a vibration-resistant proton transfer Reaction Mass spectrometry (PTR-MS) with a global positioning system receiver, modified box vehicle, and geographic information system (GIS) software. The PTR-MS, mounted on a vehicle, sends VOC data and vehicle position information to the GIS software. These data are used to image the space distribution of VOCs in real time while the vehicle platform is in motion and the VOC sources are precisely traced using the GIS. The spatial data resolution of the M-PTR-MS is typically 0.8 m. The limits of detection, sensitivity, and repeatability of the M-PTR-MS are 43.5 ppt, 347 counts ppb−1, and 2.4% (RSD, n = 5), respectively. The intensity of reagent ions is stable over 8 h (RSD = 0.45%). Compared with commercial PTR-MS equipment, the M-PTR-MS demonstrated high consistency, with a correlation coefficient of 92.665%. Several field experiments were conducted in China using the M-PTR-MS. In one field experiment, the VOC distribution along three different routes was surveyed; the navigation monitoring lasted 1.8 h over a distance of 26.7 km at an average speed of 15 km h−1. The VOC sources in an industrial park were identified by analyzing the components near different factories. The main species from a VOC source in an underground garage was related to paint. The M-PTR-MS instrument can be used by environmental protection agencies to trace VOC pollution sources in real time, and by researchers to survey VOC emissions in regions of concern.
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Standardization study of expiratory conditions for on-line breath testing by proton transfer Reaction Mass spectrometry.
Analytical biochemistry, 2019Co-Authors: Xue Zou, Hongmei Wang, Chengyin Shen, Yannan ChuAbstract:Breath testing is a noninvasive method with potential for diagnosing cancers and has been regarded as one of the research hotspots in metabolomics. In the conventional breath sampling process, however, degradation of exhaled metabolites and introduction of impurities from sampling bags or tubes limit the development of breath research. To solve this problem, we previously developed an on-line breath sampling system, which can directly deliver exhaled gases from the mouth to the proton transfer Reaction Mass spectrometry (PTR-MS) breath analysis instrument. To establish a standard expiratory method for this system, four parameters that may affect the concentrations of exhaled volatile organic compounds (VOCs) were studied. We found inhaled gas volume, breath holding time, mouth rinsing, and ambient air all affected the exhaled VOCs. In particular, the breath holding time and mouth rinsing significantly affected the VOCs which originate from the oral cavity. Therefore, these four parameters should be taken into account in future on-line breath testing.
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V-shaped ion funnel proton transfer Reaction Mass spectrometry
Instrumentation Science & Technology, 2019Co-Authors: Yujie Wang, Kexiu Dong, Yannan ChuAbstract:AbstractA V-shaped ion funnel (IF) drift tube was developed for proton transfer Reaction Mass spectrometry (PTR-MS). The ion transmissions were characterized at variable radio frequency voltages an...
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Detection of Ketones by a Novel Technology: Dipolar Proton Transfer Reaction Mass Spectrometry (DP-PTR-MS).
Journal of the American Society for Mass Spectrometry, 2017Co-Authors: Yue Pan, Chengyin Shen, Hongmei Wang, Huang Chaoqun, Qiangling Zhang, Wenzhao Zhou, Xue Zou, Yannan ChuAbstract:Proton transfer Reaction Mass spectrometry (PTR-MS) has played an important role in the field of real-time monitoring of trace volatile organic compounds (VOCs) due to its advantages such as low limit of detection (LOD) and fast time response. Recently, a new technology of proton extraction Reaction Mass spectrometry (PER-MS) with negative ions OH– as the reagent ions has also been presented, which can be applied to the detection of VOCs and even inorganic compounds. In this work, we combined the functions of PTR-MS and PER-MS in one instrument, thereby developing a novel technology called dipolar proton transfer Reaction Mass spectrometry (DP-PTR-MS). The selection of PTR-MS mode and PER-MS mode was achieved in DP-PTR-MS using only water vapor in the ion source and switching the polarity. In this experiment, ketones (denoted by M) were selected as analytes. The ketone (molecular weight denoted by m) was ionized as protonated ketone [M + H]+ [Mass-to-charge ratio (m/z) m + 1] in PTR-MS mode and deprotonated ketone [M – H]– (m/z m – 1) in PER-MS mode. By comparing the m/z value of the product ions in the two modes, the molecular weight of the ketone can be positively identified as m. Results showed that whether it is a single ketone sample or a mixed sample of eight kinds of ketones, the molecular weights can be detected with DP-PTR-MS. The newly developed DP-PTR-MS not only maintains the original advantages of PTR-MS and PER-MS in sensitive and rapid detection of ketones, but also can estimate molecular weight of ketones.
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On-line Detection of Volatile Sulfur Compounds in Breath Gas by Proton Transfer Reaction Mass Spectrometry
Chemical Journal of Chinese Universities-chinese, 2015Co-Authors: Chengyin Shen, Hongmei Wang, Huang Chaoqun, Lei Xia, Hongzhi Wang, Xiaojing Chen, Yannan ChuAbstract:To develop a kind of noninvasive method of breath diagnosis in diseases,much attention has been paid to the study of the relation between diseases and volatile organic compounds in human breath gas.However,the gas in oral cavity was usually ignored in many studies of breath gas. The bad breath odor of a participant was studied by a home-made proton transfer Reaction Mass spectrometer( PTR-MS). The breath via the mouth,breath via the nose and the air in the mouth cavity were monitored with the mode of multiple ion detect scans. The results show that three different volatile sulfur compounds that cause bad breath odor should be attributed to different sources. The source of methyl mercaptan in breath is oral cavity,and the source of hydrogen sulphide and dimethylsulfide in breath is lung or respiratory tract. The related result is very important to sampling and detection of breath gas.
Armin Hansel - One of the best experts on this subject based on the ideXlab platform.
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Advances in proton transfer Reaction Mass spectrometry (PTR-MS): applications in exhaled breath analysis, food science, and atmospheric chemistry
Journal of breath research, 2019Co-Authors: Joachim D. Pleil, Armin Hansel, Jonathan BeauchampAbstract:This report discusses advances in instrumentation based on soft chemical ionization followed by high-resolution real-time Mass spectrometry (HR-MS), specifically in relation to developments in proton transfer Reaction Mass spectrometry (PTR-MS) technology. It is part of a Journal of Breath Research series that describes recent technical developments in breath related research relevant to human health and analytical chemistry from scientific conferences. Herein we discuss the current state of PTR-MS as presented at the 8th International Conference on Proton Transfer Reaction - Mass Spectrometry held in Innsbruck, Austria, February 2-8, 2019, attended by the authors.
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characterization of an olfactometer by proton transfer Reaction Mass spectrometry
Measurement Science and Technology, 2010Co-Authors: Jonathan Beauchamp, Andrea Buettner, Armin Hansel, Johannes Frasnelli, M Scheibe, Thomas HummelAbstract:The performance of a commercial olfactometer instrument, which produces odorant pulses of defined duration and concentration, was characterized using proton-transfer-Reaction Mass spectrometry (PTR-MS). Direct coupling of the PTR-MS instrument with the olfactometer enabled on-line evaluation of the rapidly delivered aroma pulses. Tests were made with a selection of four odorous compounds: hydrogen sulfide, 2,3-butanedione, ethyl butanoate and ethyl hexanoate. Odour concentrations and stimulus durations for these compounds were monitored directly at the olfactometer delivery port via the respective PTR-MS signals. The performance of the olfactometer was found to be dependent on pulse duration. A decrease over time in maximum intensity for identical pulses over an extended duration showed headspace concentration depletions for compounds sourced from a water solution, indicative of gas/liquid partitioning. Such changes were not present using odours sourced from a cylinder or, presumably, when using liquid odours at neat concentrations. In conclusion, while an olfactometer provides stimuli with good reproducibility, the concept is subject to certain limitations that must be appreciated by the experimenter for accurate application of this technique.
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trace gas monitoring at the mauna loa baseline observatory using proton transfer Reaction Mass spectrometry
International Journal of Mass Spectrometry, 2003Co-Authors: T Karl, Werner Lindinger, Armin Hansel, T D Mark, David HoffmannAbstract:Real time monitoring of volatile organic compounds (VOCs) using a Proton-Transfer Reaction Mass Spectrometer was performed at the Mauna Loa Baseline Station (19.54N, 155.58W) in March/April 2001 (March 23, 2001–April 17, 2001). Mixing ratios for methanol, acetone, acetonitrile, isoprene and methyl vinyl ketone (MVK) plus methacrolein (MACR) ranged between 0.2 and 1.8, 0.2 and 1, 0.07 and 0.2, <0.02 and 0.3, and <0.02 and 0.5 ppbv, respectively. BioMass burning plumes transported from South-East Asia and the Indian Subcontinent across the Pacific influenced part of the measurement campaign.
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Trace gas monitoring at the Mauna Loa Baseline Observatory using Proton-Transfer Reaction Mass Spectrometry
International Journal of Mass Spectrometry, 2002Co-Authors: Thomas Karl, Armin Hansel, Werner Lindinger, Tilmann D. Märk, David HoffmannAbstract:Real time monitoring of volatile organic compounds (VOCs) using a Proton-Transfer Reaction Mass Spectrometer was performed at the Mauna Loa Baseline Station (19.54N, 155.58W) in March/April 2001 (March 23, 2001–April 17, 2001). Mixing ratios for methanol, acetone, acetonitrile, isoprene and methyl vinyl ketone (MVK) plus methacrolein (MACR) ranged between 0.2 and 1.8, 0.2 and 1, 0.07 and 0.2,
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Quantification of passive smoking using proton-transfer-Reaction Mass spectrometry
International Journal of Mass Spectrometry, 1998Co-Authors: P. Prazeller, Armin Hansel, Thomas Karl, A. Jordan, Rupert Holzinger, Werner LindingerAbstract:Abstract Using acetonitrile as the lead component, quantitative comparison between passive smoking and direct smoking was achieved by performing measurements using proton-transfer-Reaction Mass spectrometry. Staying for a working day (8 h) in a smoke laden environment, as is typical for pubs where guests are smoking heavily, is equivalent to smoking one to two cigarettes.
Ambarish Goswami - One of the best experts on this subject based on the ideXlab platform.
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Reaction Mass pendulum rmp an explicit model for centroidal angular momentum of humanoid robots
International Conference on Robotics and Automation, 2007Co-Authors: Sunghee Lee, Ambarish GoswamiAbstract:A number of conceptually simple but behavior-rich "inverted pendulum" humanoid models have greatly enhanced the understanding and analytical insight of humanoid dynamics. However, these models do not incorporate the robot's angular momentum properties, a critical component of its dynamics. We introduce the Reaction Mass pendulum (RMP) model, a 3D generalization of the better-known Reaction wheel pendulum. The RMP model augments the existing models by compactly capturing the robot's centroidal momenta through its composite rigid body (CRB) inertia. This model provides additional analytical insights into legged robot dynamics, especially for motions involving dominant rotation, and leads to a simpler class of control laws. In this paper we show how a humanoid robot of general geometry and dynamics can be mapped into its equivalent RMP model. A movement is subsequently mapped to the time evolution of the RMP. We also show how an "inertia shaping" control law can be designed based on the RMP.
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ICRA - Reaction Mass Pendulum (RMP): An explicit model for centroidal angular momentum of humanoid robots
Proceedings 2007 IEEE International Conference on Robotics and Automation, 2007Co-Authors: Sunghee Lee, Ambarish GoswamiAbstract:A number of conceptually simple but behavior-rich "inverted pendulum" humanoid models have greatly enhanced the understanding and analytical insight of humanoid dynamics. However, these models do not incorporate the robot's angular momentum properties, a critical component of its dynamics. We introduce the Reaction Mass pendulum (RMP) model, a 3D generalization of the better-known Reaction wheel pendulum. The RMP model augments the existing models by compactly capturing the robot's centroidal momenta through its composite rigid body (CRB) inertia. This model provides additional analytical insights into legged robot dynamics, especially for motions involving dominant rotation, and leads to a simpler class of control laws. In this paper we show how a humanoid robot of general geometry and dynamics can be mapped into its equivalent RMP model. A movement is subsequently mapped to the time evolution of the RMP. We also show how an "inertia shaping" control law can be designed based on the RMP.
Franco Biasioli - One of the best experts on this subject based on the ideXlab platform.
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Mead fermentation monitoring by proton transfer Reaction Mass spectrometry and medium infrared probe
European Food Research and Technology, 2016Co-Authors: Martha Cecilia Quicazán De Cuenca, Andrea Romano, Flavio Ciesa, Peter Robatscher, Matteo Scampicchio, Franco BiasioliAbstract:Mead is a traditional alcoholic beverage similar to wine, but obtained by the fermentation of a diluted solution of honey. The rate of fermentation is generally monitored by the measurement of a set of physicochemical variables such as pH, titratable acidity, Brix degrees, sugars and ethanol concentration. This work aims at developing a new monitoring method for alcoholic fermentations that is based on two on-line approaches: a proton transfer Reaction Mass spectrometry (PTR-MS) and a fibre optic coupled attenuated total reflection (FTIR-ATR) spectroscopy. Microfermentations are performed on 100 mL musts in isothermal conditions at 20 °C. Musts consist on diluted honey solutions (24 Bx) with pollen (0.4 % w/v) and yeast (Saccharomyces cerevisiae subsp. bayanus). The effect of flavour enhancers [chilli (Capsicum annuum), clove (Eugenia caryophyllata) and a mixture of both] on the rate of fermentation was also evaluated. The results show that clove inhibits fermentation, whereas chilli increases the rate of fermentation. PTR-MS and FTIR-ATR are simple, fast and nondestructive techniques able to monitor the fermentation process without the need of sample preparation, extraction or pre-concentration steps.
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The Application of Proton Transfer Reaction Mass Spectrometry to the Analysis of Foods
Reference Module in Food Science, 2016Co-Authors: Brian Farneti, Sine Yener, Iuliia Khomenko, Luca Cappellin, Franco BiasioliAbstract:The instrumental characterization of volatile organic compounds (VOCs) is essential to have a precise, reliable, and reproducible estimation of food aroma and, therefore, of the overall product quality. In this article we will list the main characteristics of PTR-MS (proton transfer Reaction Mass spectrometry) and its application in the agri-food chain research. The high time resolution brought by this technology allows real-time monitoring of fast food processes and rapid and noninvasive VOC fingerprinting.
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Proton transfer Reaction–Mass spectrometry: online and rapid determination of volatile organic compounds of microbial origin
Applied Microbiology and Biotechnology, 2015Co-Authors: Andrea Romano, Vittorio Capozzi, Giuseppe Spano, Franco BiasioliAbstract:Analytical tools for the identification and quantification of volatile organic compounds (VOCs) produced by microbial cultures have countless applications in an industrial and research context which are still not fully exploited. The various techniques for VOC analysis generally arise from the application of different scientific and technological philosophies, favoring either sample throughput or chemical information. Proton transfer Reaction–Mass spectrometry (PTR-MS) represents a valid compromise between the two aforementioned approaches, providing rapid and direct measurements along with highly informative analytical output. The present paper reviews the main applications of PTR-MS in the microbiological field, comprising food, environmental, and medical applications.
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Differentiation of specialty coffees by proton transfer Reaction-Mass spectrometry
Food Research International, 2013Co-Authors: Özgül Özdestan, Andrea Romano, Luca Cappellin, Saskia M. Van Ruth, Martin Alewijn, Alex Koot, Franco BiasioliAbstract:In the coffee sector a diversity of certifications is available, with the most well-known being organic and fair trade. Intrinsic markers of products may help to assure the authenticity of food products and complement administrative controls. In the present study 110 market coffees with special production traits were characterized by high sensitivity proton transfer Reaction Mass spectrometry (HS PTR-MS) and volatiles were tentatively identified by PTR-time of flight MS. Espresso coffees, Kopi Luwak coffee and organic coffees could be distinguished by their profiles of volatile compounds with the help of chemometrics. A PLS-DA classification model was estimated to classify the organic and regular coffees by their HS PTR-MS Mass spectra. Cross validation showed correct prediction of 42 out of the 43 (98%) organic coffee samples and 63 out of the 67 (95%) regular coffee samples. Therefore, the presented strategy is a promising approach to rapid organic coffee authentication.
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Assessment of Trentingrana cheese ageing by proton transfer Reaction-Mass spectrometry and chemometrics
International Dairy Journal, 2007Co-Authors: Eugenio Aprea, Franco Biasioli, Flavia Gasperi, D. Mott, Federico Marini, Tilmann D. MärkAbstract:Proton transfer Reaction-Mass spectrometry (PTR-MS) data have been analysed by chemometric techniques to monitor cheese ageing by means of on-line direct head-space gas analysis. Twenty cheese loaves of Trentingrana, a trademarked cheese produced in northern Italy, of different origin and ripening degree, were sampled over the whole Trentingrana production area. An increase of the spectral intensity with ripening has been observed for most of the PTR-MS peaks and a univariate analysis identified 16 Mass peaks that were significantly different for ripened and young cheeses, respectively. Moreover, the usefulness of different discriminant analyses and class modelling techniques have been investigated. Discriminant Partial Least Squares analysis, while indicating average behaviour and possible outliers, was not able to correctly classify all samples. Soft class modelling performed better and allowed a 100% correct classification. Partial least square calibration predicted the ageing time of each loaf with reasonable accuracy with a maximum cross-validation error of 3.5 months.
