Callback Service

Undefined

The world's leading PTR-MS company

Providing ultra-sensitive solutions for real-time trace gas analysis since 1998

Navigation

You are here

Scientific Articles - PTR-MS Bibliography

Welcome to the new IONICON scientific articles database!

Publications

Found 767 results
Title [ Year(Asc)]
2015
[1679] Hayeck, N., B. Temime-Roussel, S. Gligorovski, A. Mizzi, R. Gemayel, S. Tlili, P. Maillot, N. Pic, T. Vitrani, I. Poulet, et al., "Monitoring of organic contamination in the ambient air of microelectronic clean room by proton-transfer reaction/time-of-flight/mass spectrometry (PTR-ToF-MS)", International Journal of Mass Spectrometry, Oct, 2015.
Link: http://dx.doi.org/10.1016/j.ijms.2015.09.017
Abstract
<p>The organic contamination has been recently considered as the most important problem for the photolithography world in the semiconductor industry, especially when the photolithographic methods moved from 130 nm node to 32 nm node. One of the most common organic compounds found in photolithography areas of the clean room is Trimethylsilanol (TMS), which can adsorb on the optical lenses forming a thin molecular layer, hence causing damages. Salt crystal formation is another potential threat for the optical devices. In the clean rooms, this salt is produced by a light-induced reaction between ammonia and an acid. In the context of semiconductor industry, the involved acid is usually the acetic acid produced by hydrolysis from propylene glycol methyl ether acetate (PGMEA), a commonly used organic compound in the photolithography. Here, we present an innovative analytical method using a state-of-the-art proton-transfer reaction&ndash;time-of-flight&ndash;mass spectrometer (PTR&ndash;ToF&ndash;MS) for on-line and continuous survey of volatile organic compounds (VOCs) with an emphasis on TMS and PGMEA. The effect of relative humidity on the detection and fragmentation of these organic compounds was assessed. The new analytical method is operated in a real life clean room environment and the results were compared with those obtained with off-line measurements using automated thermal desorber&ndash;gas chromatography&ndash;mass spectrometry (ATD&ndash;GC&ndash;MS) as reference method. The contamination sources were detected and identified, which is of paramount importance for the microelectronic fabrication plant. The trapping efficiency of the chemical filters used for AMCs filtration in the photolithography zone was determined.</p>
[1655] Materic, D., M. Lanza, P. Sulzer, J. Herbig, D. Bruhn, C. Turner, N. Mason, and V. Gauci, "Monoterpene separation by coupling proton transfer reaction time-of-flight mass spectrometry with fastGC", Analytical and Bioanalytical Chemistry, Aug, 2015.
Link: http://dx.doi.org/10.1007/s00216-015-8942-5
Abstract
<p>Proton transfer reaction mass spectrometry (PTR-MS) is a well-established technique for real-time analysis of volatile organic compounds (VOCs). Although it is extremely sensitive (with sensitivities of up to 4500 cps/ppbv, limits of detection &lt;1 pptv and the response times of approximately 100 ms), the selectivity of PTR-MS is still somewhat limited, as isomers cannot be separated. Recently, selectivity-enhancing measures, such as manipulation of drift tube parameters (reduced electric field strength) and using primary ions other than H3O+, such as NO+ and O2 +, have been introduced. However, monoterpenes, which belong to the most important plant VOCs, still cannot be distinguished so more traditional technologies, such as gas chromatography mass spectrometry (GC-MS), have to be utilised. GC-MS is very time consuming (up to 1 h) and cannot be used for real-time analysis. Here, we introduce a sensitive, near-to-real-time method for plant monoterpene research&mdash;PTR-MS coupled with fastGC. We successfully separated and identified six of the most abundant monoterpenes in plant studies (α- and β-pinenes, limonene, 3-carene, camphene and myrcene) in less than 80 s, using both standards and conifer branch enclosures (Norway spruce, Scots pine and black pine). Five monoterpenes usually present in Norway spruce samples with a high abundance were separated even when the compound concentrations were diluted to 20 ppbv. Thus, fastGC-PTR-ToF-MS was shown to be an adequate one-instrument solution for plant monoterpene research.</p>
[1711] Materic, D., M. Lanza, P. Sulzer, J. Herbig, D. Bruhn, C. Turner, N. Mason, and V. Gauci, "Monoterpene separation by coupling proton transfer reaction time-of-flight mass spectrometry with fastGC.", Anal Bioanal Chem, vol. 407, pp. 7757–7763, Oct, 2015.
Link: http://dx.doi.org/10.1007/s00216-015-8942-5
Abstract
<p>Proton transfer reaction mass spectrometry (PTR-MS) is a well-established technique for real-time analysis of volatile organic compounds (VOCs). Although it is extremely sensitive (with sensitivities of up to 4500 cps/ppbv, limits of detection &lt;1 pptv and the response times of approximately 100 ms), the selectivity of PTR-MS is still somewhat limited, as isomers cannot be separated. Recently, selectivity-enhancing measures, such as manipulation of drift tube parameters (reduced electric field strength) and using primary ions other than H3O(+), such as NO(+) and O2 (+), have been introduced. However, monoterpenes, which belong to the most important plant VOCs, still cannot be distinguished so more traditional technologies, such as gas chromatography mass spectrometry (GC-MS), have to be utilised. GC-MS is very time consuming (up to 1 h) and cannot be used for real-time analysis. Here, we introduce a sensitive, near-to-real-time method for plant monoterpene research-PTR-MS coupled with fastGC. We successfully separated and identified six of the most abundant monoterpenes in plant studies (α- and β-pinenes, limonene, 3-carene, camphene and myrcene) in less than 80 s, using both standards and conifer branch enclosures (Norway spruce, Scots pine and black pine). Five monoterpenes usually present in Norway spruce samples with a high abundance were separated even when the compound concentrations were diluted to 20 ppbv. Thus, fastGC-PTR-ToF-MS was shown to be an adequate one-instrument solution for plant monoterpene research.</p>
[1825] Eichler, P., M. Müller, B. D{\textquotesingle}Anna, and A. Wisthaler, "A novel inlet system for online chemical analysis of semi-volatile submicron particulate matter", Atmospheric Measurement Techniques, vol. 8, pp. 1353–1360, mar, 2015.
Abstract
<p>We herein present a novel modular inlet system designed to be coupled to low-pressure gas analyzers for online chemical characterization of semi-volatile submicron particles. The &quot;chemical analysis of aerosol online&quot; (CHARON) inlet consists of a gas-phase denuder for stripping off gas-phase analytes, an aerodynamic lens for particle collimation combined with an inertial sampler for the particle-enriched flow and a thermodesorption unit for particle volatilization prior to chemical analysis. The denuder was measured to remove gas-phase organics with an efficiency &gt; 99.999% and to transmit particles in the 100&ndash;750 nm size range with a 75&ndash;90% efficiency. The measured average particle enrichment factor in the subsampling flow from the aerodynamic lens was 25.6, which is a factor of 3 lower than the calculated theoretical optimum. We coupled the CHARON inlet to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) which quantitatively detects most organic analytes and ammonia. The combined CHARON-PTR-ToF-MS setup is thus capable of measuring both the organic and the ammonium fraction in submicron particles in real time. Individual organic compounds can be detected down to levels of 10&ndash;20 ng m&minus;3. Two proof-of-principle studies were carried out for demonstrating the analytical power of this new instrumental setup: (i) oxygenated organics and their partitioning between the gas and the particulate phase were observed from the reaction of limonene with ozone and (ii) nicotine was measured in cigarette smoke particles demonstrating that selected organic target compounds can be detected in submicron particles in real time.</p>
[1664] Zannoni, N.., V.. Gros, M.. Lanza, R.. Sarda, B.. Bonsang, C.. Kalogridis, S.. Preunkert, M.. Legrand, C.. Jambert, C.. Boissard, et al., "OH reactivity and concentrations of Biogenic Volatile Organic Compounds in a Mediterranean forest of downy oak trees", Atmos. Chem. Phys. Discuss., vol. 15, pp. 22047--22095, 2015.
Link: http://dx.doi.org/10.5194/acpd-15-22047-2015
Abstract
<p>Abstract. Understanding the processes between the biosphere and the atmosphere is challenged by the difficulty to determine with enough accuracy the composition of the atmosphere. Total OH reactivity, which is defined as the total loss of the hydroxyl radical in the atmosphere, has proved to be an excellent tool to identify indirectly the important reactive species in ambient air. High levels of unknown reactivity were found in several forests worldwide and were often higher than at urban sites. Such results demonstrated the importance of OH reactivity for characterizing two of the major unknowns currently present associated to forests: the set of primary emissions from the canopy to the atmosphere and biogenic compounds oxidation pathways. Previous studies also highlighted the need to quantify OH reactivity and missing OH reactivity at more forested sites. Our study presents results of a field experiment conducted during late spring 2014 at the forest site at the Observatoire de Haute Provence, OHP, France. The forest is mainly composed of downy oak trees, a deciduous tree species characteristic of the Mediterranean region. We deployed the Comparative Reactivity Method and a set of state-of-the-art techniques such as Proton Transfer Reaction-Mass Spectrometry and Gas Chromatography to measure the total OH reactivity, the concentration of volatile organic compounds and main atmospheric constituents at the site. We sampled the air masses at two heights: 2 m, i.e. inside the canopy, and 10 m, i.e. above the canopy, where the mean canopy height is 5 m. We found that the OH reactivity at the site mainly depended on the main primary biogenic species emitted by the forest, which was isoprene and to a lesser extent by its degradation products and long lived atmospheric compounds (up to 26 % during daytime). We determined that the daytime total measured reactivity equaled the calculated reactivity obtained from the concentrations of the compounds measured at the site. Hence, no significant missing reactivity is reported in this specific site, neither inside, nor above the canopy. However, during two nights we reported a missing fraction of OH reactivity up to 50 %, possibly due to unmeasured oxidation products. Our results confirm the weak intra canopy oxidation, already suggested in a previous study focused on isoprene fluxes. They also demonstrate how helpful can be the OH reactivity as a tool to clearly characterize the suite of species present in the atmosphere. We show that our result of reactivity is among the highest reported in forests worldwide and stress the importance to quantify OH reactivity at more and diverse Mediterranean forests.</p>
[1708] Fu, H., R. Ciuraru, Y. Dupart, M. Passananti, L. Tinel, S. Rossignol, S. Perrier, J. D Donaldson, J. Chen, and C. George, "Photosensitized Production of Atmospherically Reactive Organic Compounds at the Air/Aqueous Interface.", J Am Chem Soc, vol. 137, pp. 8348–8351, Jul, 2015.
Link: http://dx.doi.org/10.1021/jacs.5b04051
Abstract
<p>We report on experiments that probe photosensitized chemistry at the air/water interface, a region that does not just connect the two phases but displays its own specific chemistry. Here, we follow reactions of octanol, a proxy for environmentally relevant soluble surfactants, initiated by an attack by triplet-state carbonyl compounds, which are themselves concentrated at the interface by the presence of this surfactant. Gas-phase products are determined using PTR-ToF-MS, and those remaining in the organic layer are determined by ATR-FTIR spectroscopy and HPLC-HRMS. We observe the photosensitized production of carboxylic acids as well as unsaturated and branched-chain oxygenated products, compounds that act as organic aerosol precursors and had been thought to be produced solely by biological activity. A mechanism that is consistent with the observations is detailed here, and the energetics of several key reactions are calculated using quantum chemical methods. The results suggest that the concentrating nature of the interface leads to its being a favorable venue for radical reactions yielding complex and functionalized products that themselves could initiate further secondary chemistry and new particle formation in the atmospheric environment.</p>
[1762] Kim, S., A. Guenther, B. Lefer, J. Flynn, R. Griffin, A. P. Rutter, L. Gong, and B. Karakurt Cevik, "Potential Role of Stabilized Criegee Radicals in Sulfuric Acid Production in a High Biogenic VOC Environment", Environmental Science & Technology, vol. 49, pp. 3383–3391, Mar, 2015.
Link: http://dx.doi.org/10.1021/es505793t
Abstract
<p>We present field observations made in June 2011 downwind of Dallas&ndash;Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO2 and water vapor. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H2SO4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment.</p>
[1714] Bergamaschi, M.., F.. Biasioli, L.. Cappellin, A.. Cecchinato, C.. Cipolat-Gotet, A.. Cornu, F.. Gasperi, B.. Martin, and G.. Bittante, "Proton transfer reaction time-of-flight mass spectrometry: A high-throughput and innovative method to study the influence of dairy system and cow characteristics on the volatile compound fingerprint of cheeses.", J Dairy Sci, vol. 98, pp. 8414–8427, Dec, 2015.
Link: http://dx.doi.org/10.3168/jds.2015-9803
Abstract
<p>The aim of this work was to study the effect of dairy system and individual cow-related factors on the volatile fingerprint of a large number of individual model cheeses analyzed by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). A total of 1,075 model cheeses were produced using milk samples collected from individual Brown Swiss cows reared in 72 herds located in mountainous areas of Trento province (Italy). The herds belonged to 5 main dairy systems ranging from traditional to modern and the cows presented different daily milk yields (24.6&plusmn;7.9kg &times; d(-1)), stages of lactation (199&plusmn;138 d in milk), and parities (2.7&plusmn;1.8). The PTR-ToF-MS revealed 619 peaks, of which the 240 most intense were analyzed, and 61 of these were tentatively attributed to relevant volatile organic compounds on the basis of their fragmentation patterns and data from the literature. Principal component analysis was used to convert the multiple responses characterizing the PTR-ToF-MS spectra into 5 synthetic variables representing 62% of the total information. These principal components were related to groups of volatile compounds tentatively attributed to different peaks and used to investigate the relationship of the volatile compound profile obtained by PTR-ToF-MS to animal and farm characteristics. Lactation stage is related to 4 principal components which brought together 52.9% of the total variance and 57.9% of the area of analyzed peaks. In particular, 2 principal components were positively related to peaks tentatively attributed to aldehydes and ketones and negatively related to alcohols, esters, and acids, which displayed a linear increase during lactation. The second principal component was affected by dairy system; it was higher in the modern system in which cows received total mixed rations. The third principal component was positively related to daily milk production. In summary, we report the first application of this innovative, high-throughput technique to study the effects of dairy system and individual animal factors on volatile organic compounds of model cheeses. Individual cheesemaking procedures together with this spectrometric technique open new avenues for genetic selection of dairy species with respect to both milk and cheese quality.</p>
[1639] Romano, A., V. Capozzi, G. Spano, and F. Biasioli, "Proton transfer reaction-mass spectrometry: online and rapid determination of volatile organic compounds of microbial origin.", Appl Microbiol Biotechnol, vol. 99, pp. 3787–3795, May, 2015.
Link: http://dx.doi.org/10.1007/s00253-015-6528-y
Abstract
<p>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.</p>
[1626] Warneke, C.., P.. Veres, S.. M. Murphy, J.. Soltis, R.. A. Field, M.. G. Graus, A.. Koss, S.-M.. Li, R.. Li, B.. Yuan, et al., "PTR-QMS versus PTR-TOF comparison in a region with oil and natural gas extraction industry in the Uintah Basin in 2013", Atmos. Meas. Tech., vol. 8, pp. 411–420, 2015.
Link: http://dx.doi.org/10.5194/amt-8-411-2015
Abstract
Here we compare volatile organic compound (VOC) measurements using a standard proton-transfer-reaction quadrupole mass spectrometer (PTR-QMS) with a new proton-transfer-reaction time of flight mass spectrometer (PTR-TOF) during the Uintah Basin Winter Ozone Study 2013 (UBWOS2013) field experiment in an oil and gas field in the Uintah Basin, Utah. The PTR-QMS uses a quadrupole, which is a mass filter that lets one mass to charge ratio pass at a time, whereas the PTR-TOF uses a time of flight mass spectrometer, which takes full mass spectra with typical 0.1 s–1 min integrated acquisition times. The sensitivity of the PTR-QMS in units of counts per ppbv (parts per billion by volume) is about a factor of 10–35 times larger than the PTR-TOF, when only one VOC is measured. The sensitivity of the PTR-TOF is mass dependent because of the mass discrimination caused by the sampling duty cycle in the orthogonal-acceleration region of the TOF. For example, the PTR-QMS on mass 33 (methanol) is 35 times more sensitive than the PTR-TOF and for masses above 120 amu less than 10 times more. If more than 10–35 compounds are measured with PTR-QMS, the sampling time per ion decreases and the PTR-TOF has higher signals per unit measuring time for most masses. For UBWOS2013 the PTR-QMS measured 34 masses in 37 s and on that timescale the PTR-TOF is more sensitive for all masses. The high mass resolution of the TOF allows for the measurements of compounds that cannot be separately detected with the PTR-QMS, such as oxidation products from alkanes and cycloalkanes emitted by oil and gas extraction. PTR-TOF masses do not have to be preselected, allowing for identification of unanticipated compounds. The measured mixing ratios of the two instruments agreed very well (R2 ≥ 0.92 and within 20%) for all compounds and masses monitored with the PTR-QMS.
[1702] Masi, E., A. Romani, C. Pandolfi, D. Heimler, and S. Mancuso, "PTR-TOF-MS analysis of volatile compounds in olive fruits.", J Sci Food Agric, vol. 95, pp. 1428–1434, May, 2015.
Link: http://dx.doi.org/10.1002/jsfa.6837
Abstract
<p>Volatile compounds of Cellina di Nardò and Ogliarola Barese, two typical Italian olive varieties, have been characterised at different ripening stages. Proton transfer reaction-time-of-flight-mass spectrometry (PTR-TOF-MS) was used for the first time on these fruits with the aim of characterising the volatile profile and, in the case of Ogliarola, the changes which may occur during the maturation process.PTR-TOF-MS does not involve any sample pre-treatment, and allows high-resolution measurements, large spectra and small fragmentation of the volatiles. Therefore it allows both compound identification and data statistical treatments. In the present work, about 40 compounds that contribute to the discrimination between samples of the two varieties have been identified.Three groups of compounds were identified: (1) compounds that are typical of mature fruits of Ogliarola, (2) compounds that tend to decrease during the change from green to mature fruits, and (3) compounds that increase during the maturation process.</p>
[1707] Zein, A. El, C. Coeur, E. Obeid, A. Lauraguais, and T. Fagniez, "Reaction Kinetics of Catechol (1,2-Benzenediol) and Guaiacol (2-Methoxyphenol) with Ozone.", J Phys Chem A, vol. 119, pp. 6759–6765, Jul, 2015.
Link: http://dx.doi.org/10.1021/acs.jpca.5b00174
Abstract
<p>The kinetic reactions of 1,2-benzenediol (catechol) and 2-methoxyphenol (guaiacol) with ozone were studied in a simulation chamber (8 m(3)) under dark conditions. The rate coefficients were measured at 294 &plusmn; 2 K, atmospheric pressure and dry conditions (relative humidity, RH &lt; 1%), except for 1,2-benzenediol where they were also measured as a function of relative humidity (RH = 1-80%). The concentrations of organic compounds were followed by a PTR-ToF-MS for a continuous monitoring of gas-phase species. The O3 rate coefficients were obtained using both the pseudo-first-order and relative rate methods. The values (in cm(3) molecule(-1) s(-1)) determined for catechol and guaiacol under dry conditions are (13.5 &plusmn; 1.1) &times; 10(-18) and (0.40 &plusmn; 0.31) &times; 10(-18), respectively. The rate coefficient of catechol was found to be independent of RH below 20% and above 60%, whereas for RH between 20% and 60% it decreases with increasing RH. The determined rate coefficients have been used to evaluate the atmospheric lifetime of each compound with respect to O3. To our knowledge, this study represents the first determination of the ozone rate coefficient with guaiacol and is also the first kinetic investigation for the influence of the relative humidity on the oxygenated aromatic ozonolysis.</p>
[1576] Lanza, M., J. W. Acton, P. Sulzer, K. Breiev, S. Juerschik, A. Jordan, E. Hartungen, G. Hanel, L. Maerk, T. D. Maerk, et al., "Selective reagent ionisation-time of flight-mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances", Journal of Mass Spectrometry, vol. 50, pp. 427–431, 2015.
Link: http://dx.doi.org/10.1002/jms.3514
Abstract
In this study we demonstrate the potential of selective reagent ionisation-time of flight-mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called ‘synthacaine’, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O+ result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O+ and NO+) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions. Copyright © 2015 John Wiley & Sons, Ltd.
[1638] Lanza, M., J. W Acton, P. Sulzer, K. Breiev, S. Jürschik, A. Jordan, E. Hartungen, G. Hanel, L. Märk, T. D. Märk, et al., "Selective reagent ionisation-time of flight-mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances.", J Mass Spectrom, vol. 50, pp. 427–431, Feb, 2015.
Link: http://dx.doi.org/10.1002/jms.3514
Abstract
<p>In this study we demonstrate the potential of selective reagent ionisation-time of flight-mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called &#39;synthacaine&#39;, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O(+) result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O(+) and NO(+)) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions.</p>
[1732] Mancuso, S., C. Taiti, N. Bazihizina, C. Costa, P. Menesatti, L. Giagnoni, M. Arenella, P. Nannipieri, and G. Renella, "Soil volatile analysis by proton transfer reaction-time of flight mass spectrometry (PTR-TOF-{MS})", Applied Soil Ecology, vol. 86, pp. 182¬タモ191, Feb, 2015.
Link: http://dx.doi.org/10.1016/j.apsoil.2014.10.018
Abstract
<p>We analyzed the volatile organic compounds (VOCs) emitted from different soils by using the PTR-MS-TOF technique under laboratory conditions and compared them with soil chemical biochemical activities. The emitted VOCs were related to soil microbial biomass, soil respiration and some soil enzyme activities so as to evaluate if size and activity of soil microbial communities influenced the soil VOCs profiles. Our results showed that the emitted VOCs discriminated between soils with different properties and management, and differences in the VOCs emission profiles were likely related to the active metabolic pathways in the microbial communities of the three studied soil. Our results also showed that some soil enzyme activities such as β-glucosidase and arylsulfatase were possibly involved in the release of compounds fueling microbial metabolic pathways leading to the production of specific VOCs. It was concluded that the PTR-MS-TOF technique is suitable for analyze VOCs emission from soil and that studies comparing soil enzyme activities and soil volatile profiles can reveal the origin of VOCs and give further insights on microbial activity and soil functionality.</p>
[1793] Sun, K., K. Cady-Pereira, D. J. Miller, L. Tao, M. A. Zondlo, J. B. Nowak, JA. Neuman, T. Mikoviny, M. Müller, A. Wisthaler, et al., "Validation of TES ammonia observations at the single pixel scale in the San Joaquin Valley during DISCOVER-AQ", Journal of Geophysical Research: Atmospheres, vol. 120, pp. 5140–5154, 2015.
Link: http://onlinelibrary.wiley.com/doi/10.1002/2014JD022846/full
Abstract
<p>Ammonia measurements from a vehicle-based, mobile open-path sensor and those from aircraft were compared with Tropospheric Emission Spectrometer (TES) NH3 columns at the pixel scale during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality field experiment. Spatial and temporal mismatches were reduced by having the mobile laboratory sample in the same areas as the TES footprints. To examine how large heterogeneities in the NH3 surface mixing ratios may affect validation, a detailed spatial survey was performed within a single TES footprint around the overpass time. The TES total NH3 column above a single footprint showed excellent agreement with the in situ total column constructed from surface measurements with a difference of 2% (within the combined measurement uncertainties). The comparison was then extended to a TES transect of nine footprints where aircraft data (5&ndash;80&thinsp;ppbv) were available in a narrow spatiotemporal window (&lt;10&thinsp;km, &lt;1&thinsp;h). The TES total NH3 columns above the nine footprints agreed to within 6% of the in situ total columns derived from the aircraft-based measurements. Finally, to examine how TES captures surface spatial gradients at the interpixel scale, ground-based, mobile measurements were performed directly underneath a TES transect, covering nine footprints within &plusmn;1.5&thinsp;h of the overpass. The TES total columns were strongly correlated (R2&thinsp;=&thinsp;0.82) with the median NH3 mixing ratios measured at the surface. These results provide the first in situ validation of the TES total NH3 column product, and the methodology is applicable to other satellite observations of short-lived species at the pixel scale.</p>
[1651] R. del Rio, F., M.E.. OHara, A.. Holt, P.. Pemberton, T.. Shah, T.. Whitehouse, and C.A.. Mayhew, "Volatile Biomarkers in Breath Associated With Liver Cirrhosis - Comparisons of Pre- and Post-liver Transplant Breath Samples", EBioMedicine, Jul, 2015.
Link: http://dx.doi.org/10.1016/j.ebiom.2015.07.027
Abstract
Background: The burden of liver disease in the UK has risen dramatically and there is a need for improved diagnostics. Aims: To determine which breath volatiles are associated with the cirrhotic liver and hence diagnostically useful. Methods: A two-stage biomarker discovery procedure was used. Alveolar breath samples of 31 patients with cirrhosis and 30 healthy controls were mass spectrometrically analysed and compared (stage 1). 12 of these patients had their breath analysed after liver transplant (stage 2). Five patients were followed longitudinally as in-patients in the posttransplant period. Results: Seven volatileswere elevated in the breath of patients versus controls. Of these, five showed statistically significant decrease post-transplant: limonene, methanol, 2-pentanone, 2-butanone and carbon disulfide. On an individual basis limonene has the best diagnostic capability (the area under a receiver operating characteristic curve (AUROC) is 0.91), but this is improved by combining methanol, 2-pentanone and limonene (AUROC curve 0.95). Following transplant, limonene shows wash-out characteristics. Conclusions: Limonene,methanol and 2-pentanone are breathmarkers for a cirrhotic liver. This study raises the potential to investigate these volatiles asmarkers for early-stage liver disease. Bymonitoring the wash-out of limonene following transplant, graft liver function can be non-invasively assessed.
[1706] Aprea, E., A. Romano, E. Betta, F. Biasioli, L. Cappellin, M. Fanti, and F. Gasperi, "Volatile compound changes during shelf life of dried Boletus edulis: comparison between SPME-GC-MS and PTR-ToF-MS analysis.", J Mass Spectrom, vol. 50, pp. 56–64, Jan, 2015.
Link: http://dx.doi.org/10.1002/jms.3469
Abstract
<p>Drying process is commonly used to allow long time storage of valuable porcini mushrooms (Boletus edulis). Although considered a stable product dried porcini flavour changes during storage. Monitoring of volatile compounds during shelf life may help to understand the nature of the observed changes. In the present work two mass spectrometric techniques were used to monitor the evolution of volatile compounds during commercial shelf life of dried porcini. Solid phase microextraction (SPME) coupled to gas chromatography - mass spectrometry (GC-MS) allowed the identification of 66 volatile compounds, 36 of which reported for the first time, monitored during the commercial shelf life of dried porcini. Proton transfer reaction - time of flight - mass spectrometry (PTR-ToF-MS) , a direct injection mass spectrometric technique, was shown to be a fast and sensitive instrument for the general monitoring of volatile compound evolution during storage of dried porcini. Furthermore, PTR-ToF-MS grants access to compounds whose determination would otherwise require lengthy pre-concentration and/or derivatization steps such as ammonia and small volatile amines. The two techniques, both used for the first time to study dried porcini, provided detailed description of time evolution of volatile compounds during shelf life. Alcohols, aldehydes, ketones and monoterpenes diminish during the storage while carboxylic acids, pyrazines, lactones and amines increase. The storage temperature modifies the rate of the observed changes influencing the final quality of the dried porcini. We showed the advantages of both techniques, suggesting a strategy to be adopted to follow time evolution of volatile compounds in food products during shelf life, based on the identification of compounds by GC-MS and the rapid time monitoring by PTR-ToF-MS measurements in order to maximize the advantages of both techniques.</p>
[1709] Federico, V., T. Cosimo, P. Antonio, B. Nadia, L. Valentina, M. Stefano, and A. Amedeo, "Volatile organic compounds in truffle (Tuber magnatum Pico): comparison of samples from different regions of Italy and from different seasons.", Sci Rep, vol. 5, pp. 12629, 2015.
Link: http://dx.doi.org/10.1038/srep12629
Abstract
<p>In this paper volatile organic compounds (VOCs) from Tuber magnatum fruiting bodies were analyzed using a PTR-TOF-MS instrument. The aim was to characterize the VOC&#39;s profile of the fruiting bodies and identify if any VOCs were specific to a season and geographical areas. Multiple factorial analysis (MFA) was carried out on the signals obtained by MS. Experiments using ITS region sequencing proved that the T. magnatum life cycle includes the formation of fruiting bodies at two different times of the year. The VOCs profiles diverge when different seasonal and geographical productions are considered. Using PTR-TOF-MS, compounds present at levels as low pptv were detected. This made it possible to determine both the origin of fruiting bodies (Alba and San Miniato) and the two biological phases of fruiting bodies formation in San Miniato truffles.</p>
2014
[1478] Schmidberger, T., R. Gutmann, K. Bayer, J. Kronthaler, and R. Huber, "Advanced online monitoring of cell culture off-gas using proton transfer reaction mass spectrometry", Biotechnology Progress, pp. n/a–n/a, 2014.
Link: http://dx.doi.org/10.1002/btpr.1853
Abstract
<p>Mass spectrometry has been frequently applied to monitor the O2 and CO2 content in the off-gas of animal cell culture fermentations. In contrast to classical mass spectrometry the proton transfer reaction mass spectrometry (PTR-MS) provides additional information of volatile organic compounds by application of a soft ionization technology. Hence, the spectra show less fragments and can more accurately assigned to particular compounds. In order to discriminate between compounds of non-metabolic and metabolic origin cell free experiments and fed-batch cultivations with a recombinant CHO cell line were conducted. As a result, in total eight volatiles showing high relevance to individual cultivation or cultivation conditions could be identified. Among the detected compounds methanethiol, with a mass-to-charge ratio of 49, qualifies as a key candidate in process monitoring due to its strong connectivity to lactate formation. Moreover, the versatile and complex data sets acquired by PTR MS provide a valuable resource for statistical modeling to predict non direct measurable parameters. Hence, partial least square regression was applied to the complete spectra of volatiles measured and important cell culture parameters such as viable cell density estimated (R2&thinsp;=&thinsp;0.86). As a whole, the results of this study clearly show that PTR-MS provides a powerful tool to improve bioprocess-monitoring for mammalian cell culture. Thus, specific volatiles emitted by cells and measured online by the PTR-MS and complex variables gained through statistical modeling will contribute to a deeper process understanding in the future and open promising perspectives to bioprocess control. &copy; 2014 American Institute of Chemical Engineers Biotechnol. Prog., 2014</p>
[1516] Misztal, P.. K., T.. Karl, R.. Weber, H.. H. Jonsson, A.. B. Guenther, and A.. H. Goldstein, "Airborne flux measurements of biogenic volatile organic compounds over California", Atmospheric Chemistry and Physics Discussions, vol. 14, pp. 7965–8013, Mar, 2014.
Link: http://www.atmos-chem-phys-discuss.net/14/7965/2014/acpd-14-7965-2014.html
Abstract
<p>Biogenic Volatile Organic Compound (BVOC) fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne BVOC Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a PTR-MS and a wind radome probe to directly determine fluxes of isoprene, MVK + MAC, methanol, monoterpenes, and MBO over 10 000 km of flight paths focusing on areas of California predicted to have the largest emissions of isoprene. The Fast Fourier Transform (FFT) approach was used to calculate fluxes over long transects of more than 15 km, most commonly between 50 and 150 km. The Continuous Wavelet Transformation (CWT) approach was used over the same transects to also calculate &quot;instantaneous&quot; fluxes with localization of both frequency and time independent of non-stationarities. Vertical flux divergence of isoprene is expected due to its relatively short lifetime and was measured directly using &quot;racetrack&quot; profiles at multiple altitudes. It was found to be linear and in the range 5% to 30% depending on the ratio of aircraft altitude to PBL height (z / zi). Fluxes were generally measured by flying consistently at 400 &plusmn; 50 m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to Basal Emission Factor (BEF) landcover datasets used to drive biogenic VOC (BVOC) emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mg m&minus;2 h&minus;1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions. While isoprene emissions from agricultural crop regions, shrublands, and coniferous forests were extremely low, high concentrations of methanol and monoterpenes were found above some of these regions. These observations demonstrate the ability to measure fluxes from specific sources by eddy covariance from an aircraft, and suggest the utility of measurements using fast response chemical sensors to constrain emission inventories and map out source distributions for a much broader array of trace gases than was observed in this study. This paper reports the first regional direct eddy covariance fluxes of isoprene. The emissions of VOCs measured from aircraft with 2 km spatial resolution can quantify the distribution of major sources providing the observations required for testing statewide emission inventories of these important trace gases. These measurements will be used in a future study to assess BVOC emission models and their driving variable datasets.</p>
[1560] Jankowski, M. Jan, R. Olsen, C. Nielsen, Y. Thomassen, and P. Molander, "The applicability of proton transfer reaction-mass spectrometry (PTR-{MS}) for determination of isocyanic acid ({ICA}) in work room atmospheres", Environmental Science: Processes & Impacts, 2014.
Link: http://dx.doi.org/10.1039/C4EM00363B
Abstract
<p>A method is presented for the real-time quantitative determination of isocyanic acid (ICA) in air using proton transfer reaction-mass spectrometry (PTR-MS). Quantum mechanical calculations were performed to establish the ion-polar molecule reaction rate of ICA and other isocyanates. The PTR-MS was calibrated against different ICA air concentrations and humidity conditions using Fourier transform-infrared spectroscopy (FT-IR) as quantitative reference. Based on these experiments a simple humidity dependant model was derived for correction of the PTR-MS response for ICA. The corrected PTR-MS data was linearly correlated (R2 &gt; 0.99) with the data acquired by FT-IR. The PTR-MS instrumental limit of detection (LOD) for ICA was 2.3 ppb. Humid atmospheres resulted in LODs of 3.4 and 7.8 ppb, at an absolute humidity (AH) of 4.0 and 15.5 g m-3, respectively. Furthermore, off-line sampling using denuder and impinger samplers using di-n-butylamine (DBA) as derivatization reagent was compared with PTR-MS measurements in a dynamically generated standard ICA atmosphere. Denuder (n = 4) and impinger (n = 4) sampling subsequent to liquid chromatography mass spectrometry (LC-MS) determination compared to corrected PTR-MS data resulted in recoveries of 79.6 (8.1 % RSD) and 99.9 (9.3 % RSD) %, respectively. Measurements of ICA from thermally decomposed cured 1,6-hexamethylene diisocyanate (HDI)-paint was performed used PTR-MS and denuder (n = 3) sampling. The relation between the average ICA responses using denuders (34.4 ppb) and PTR-MS (42.6 ppb) was 80.6 %, which coincided well with the relative recovery obtained from the controlled laboratory experiments using dynamically generated ICA atmospheres (79.6 %). The variability in ICA air concentration during the welding process (170 % RSDPTR-MS) illustrated the need for real-time measurements.</p>
[1636] Jankowski, M. Jan, R. Olsen, C. Jørgen Nielsen, Y. Thomassen, and P. Molander, "The applicability of proton transfer reaction-mass spectrometry (PTR-MS) for determination of isocyanic acid (ICA) in work room atmospheres.", Environ Sci Process Impacts, vol. 16, pp. 2423–2431, 2014.
Link: http://dx.doi.org/10.1039/c4em00363b
Abstract
<p>A method is presented for the real-time quantitative determination of isocyanic acid (ICA) in air using proton transfer reaction-mass spectrometry (PTR-MS). Quantum mechanical calculations were performed to establish the ion-polar molecule reaction rate of ICA and other isocyanates. The PTR-MS was calibrated against different ICA air concentrations and humidity conditions using Fourier transform-infrared spectroscopy (FT-IR) as quantitative reference. Based on these experiments a simple humidity dependant model was derived for correction of the PTR-MS response for ICA. The corrected PTR-MS data was linearly correlated (R(2) &gt; 0.99) with the data acquired by FT-IR. The PTR-MS instrumental limit of detection (LOD) for ICA was 2.3 ppb. Humid atmospheres resulted in LODs of 3.4 and 7.8 ppb, at an absolute humidity (AH) of 4.0 and 15.5 g m(-3), respectively. Furthermore, off-line sampling using denuder and impinger samplers using di-n-butylamine (DBA) as derivatization reagent was compared with PTR-MS measurements in a dynamically generated standard ICA atmosphere. Denuder (n = 4) and impinger (n = 4) sampling subsequent to liquid chromatography mass spectrometry (LC-MS) determination compared to corrected PTR-MS data resulted in recoveries of 79.6 (8.1% RSD) and 99.9 (9.3% RSD) %, respectively. Measurements of ICA from thermally decomposed cured 1,6-hexamethylene diisocyanate (HDI)-paint was performed using PTR-MS and denuder (n = 3) sampling. The relation between the average ICA responses using denuders (34.4 ppb) and PTR-MS (42.6 ppb) was 80.6%, which coincided well with the relative recovery obtained from the controlled laboratory experiments using dynamically generated ICA atmospheres (79.6%). The variability in ICA air concentration during the welding process (170% RSDPTR-MS) illustrated the need for real-time measurements.</p>
[1532] Schripp, T.., S.. Etienne, C.. Fauck, F.. Fuhrmann, L.. Märk, and T.. Salthammer, "Application of proton-transfer-reaction-mass-spectrometry for Indoor Air Quality research", Indoor Air, vol. 24, pp. 178–189, 2014.
Link: http://dx.doi.org/10.1111/ina.12061
Abstract
<p>In the field of Indoor Air Quality research, the measurement of volatile organic compounds (VOCs) demands instruments that are rapid, mobile, robust, highly sensitive and allow for simultaneous monitoring of multiple compounds. These instruments should also compensate for possible interferences from permanent gases and air humidity. Proton-transfer-reaction-mass-spectrometry (PTR-MS) has proved to be a valuable and promising technique that fits the mentioned requirements for a suitable online measuring device. In this study, five exemplary applications of PTR-MS are described: (i) release of paint additives during drying process, (ii) emission of VOCs from active hardcopy devices, (iii) reference material evaluation, (iv) diffusion studies, and (v) emission testing of building products. The examples are selected to illustrate possibilities and limitations of the PTR technique in this field of research. The quadruple-based PTR-QMS was able to determine the emission characteristics during the experiments, especially in case of depleting emission sources (e.g., reference material). This allows for chemometrical analysis of the measured release patterns and detection of underlying processes. However, PTR-QMS reaches a functional limit in case of compound identification. If identification of VOCs is necessary, the measurements need to be accompanied by GC/MS analytics or a PTR instrument with higher mass-resolution (e.g., PTR-TOF-MS).</p>
[1548] Aprea, E., L. Cappellin, F. Gasperi, F. Morisco, V. Lembo, A. Rispo, R. Tortora, P. Vitaglione, N. Caporaso, and F. Biasioli, "Application of PTR-TOF-{MS} to investigate metabolites in exhaled breath of patients affected by coeliac disease under gluten free diet", Journal of Chromatography B, vol. 966, pp. 208–213, Sep, 2014.
Link: http://dx.doi.org/10.1016/j.jchromb.2014.02.015
Abstract
<p>Coeliac disease (CD) is a common chronic inflammatory disorder of the small bowel induced in genetically susceptible people by the exposure to gliadin gluten. Even though several tests are available to assist the diagnosis, CD remains a biopsy-defined disorder, thus any non-invasive or less invasive diagnostic tool may be beneficial. The analysis of volatile metabolites in exhaled breath, given its non-invasive nature, is particularly promising as a screening tool of disease in symptomatic or non-symptomatic patients. In this preliminary study the proton transfer reaction time of flight mass spectrometry coupled to a buffered end-tidal on-line sampler to investigate metabolites in the exhaled breath of patients affected by coeliac disease under a gluten free diet was applied. Both H3O+ or NO+ were used as precursor ions. In our investigation no differences were found in the exhaled breath of CD patients compared to healthy controls. In this study, 33 subjects were enrolled: 16 patients with CD, all adhering a gluten free diet, and 17 healthy controls. CD patients did not show any symptom of the disease at the time of breath analysis; thus the absence of discrimination from healthy controls was not surprising.</p>

Pages

Featured Articles

Download Contributions to the International Conference on Proton Transfer Reaction Mass Spectrometry and Its Applications:

 

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.
Link

 

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

 

Download the latest version of the IONICON publication database as BibTeX.