"Massive emissions of carcinogenic benzenoids from paddy residue burning in North India",
, vol. 104, pp. 1703-1709, 2013.
<p>Benzenoids are organic pollutants emitted mainly by traffic and industrial sources. Here, using a combination of on-line in situ PTR-MS measurements of several benzenoids and methyl cyanide (a biomassburning tracer), satellite remote sensing data of fire counts and back trajectory of air masses at a site in Mohali, we show that massive amounts of benzenoids are released from post-harvest paddy residue burning. Two periods, one that was not influenced by paddy residue burning (period 1, 18 : 00–03 : 30 IST; 5–6 October 2012) and another which was strongly influenced by paddy residue burning (period 2, 18 : 00– 03 : 30 IST; 3–4 November 2012) were chosen to assess normal and perturbed levels. Peak values of 3830 ppb CO, 100 ppb NOx, 40 ppb toluene, 16 ppb benzene, 24 ppb for sum of all C-8 benzenoids and 13 ppb for sum of all C-9 benzenoids were observed during period 2 (number of measurements in period 2 = 570) with the average enhancements in benzenoid levels being more than 300%. The ozone formation potential of benzenoids matched that of CO, with both contributing 5 ppb/h each. Such high levels of benzenoids for 1–2 months in a year aggravate smog events and can enhance cancer risks in northwestern India.</p>
[Pleil2013] "Meeting reports for 2013: recent advances in breath biomarker research",
Journal of breath research
, vol. 7, no. 2: IOP Publishing, pp. 029001, 2013.
 "Methanol, acetaldehyde, and acetone in the surface waters of the Atlantic Ocean",
Journal of Geophysical Research: Oceans
, vol. 118, pp. 5412–5425, 2013.
<p>Oceanic methanol, acetaldehyde, and acetone concentrations were measured during an Atlantic Meridional Transect (AMT) cruise from the UK to Chile (49°N to 39°S) in 2009. Methanol (48–361 nM) and acetone (2–24 nM) varied over the track with enrichment in the oligotrophic Northern Atlantic Gyre. Acetaldehyde showed less variability (3–9 nM) over the full extent of the transect. These oxygenated volatile organic compounds (OVOCs) were also measured subsurface, with methanol and acetaldehyde mostly showing homogeneity throughout the water column. Acetone displayed a reduction below the mixed layer. OVOC concentrations did not consistently correlate with primary production or chlorophyll-a levels in the surface Atlantic Ocean. However, we did find a novel and significant negative relationship between acetone concentration and bacterial leucine incorporation, suggesting that acetone might be removed by marine bacteria as a source of carbon. Microbial turnover of both acetone and acetaldehyde was confirmed. Modeled atmospheric data are used to estimate the likely air-side OVOC concentrations. The direction and magnitude of air-sea fluxes vary for all three OVOCs depending on location. We present evidence that the ocean may exhibit regions of acetaldehyde under-saturation. Extrapolation suggests that the Atlantic Ocean represents an overall source of these OVOCs to the atmosphere at 3, 3, and 1 Tg yr−1 for methanol, acetaldehyde, and acetone, respectively.</p>
[Tsevdou2013] "Monitoring the effect of high pressure and transglutaminase treatment of milk on the evolution of flavour compounds during lactic acid fermentation using PTR-ToF-MS.",
, vol. 138, no. 4: Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens, Polytechnioupoli Zografou, Zografou 15780, Athens, Greece., pp. 2159–2167, Jun, 2013.
In this study, the effects of thermal or high hydrostatic pressure (HHP) treatment of a milk base in the absence or presence of a transglutaminase (TGase) protein cross-linking step on the flavour development of yoghurt were investigated. The presence of several tentatively identified volatile flavour compounds (VOCs), both during the enzymatic treatment and the lactic acid fermentation of the milk base, were monitored using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). The formation of the major flavour compounds (acetaldehyde, diacetyl, acetoin, and 2-butanone) followed a sigmoidal trend described by the modified Gompertz model. The HHP treatment of milk increased significantly the volatile compound formation rate whereas it did not affect the duration of the lag phase of formation, with the exception of acetaldehyde and diacetyl formation. On the contrary, the TGase cross-linking of milk did not significantly modify the formation rate of the volatile compounds but shortened the duration of the lag phase of their formation.
 "Multi-capillary-column proton-transfer-reaction time-of-flight mass spectrometry.",
J Chromatogr A
, vol. 1316, pp. 112–118, Nov, 2013.
<p>Proton-transfer-reaction time-of-flight mass-spectrometry (PTR-TOFMS) exhibits high selectivity with a resolution of around 5000m/Δm. While isobars can be separated with this resolution, discrimination of isomeric compounds is usually not possible. The coupling of a multi-capillary column (MCC) with a PTR-TOFMS overcomes these problems as demonstrated in this paper for the ketone isomers 3-heptanone and 2-methyl-3-hexanone and for different aldehydes. Moreover, fragmentation of compounds can be studied in detail which might even improve the identification. LODs for compounds tested are in the range of low ppbv and peak positions of the respective separated substances show good repeatability (RSD of the peak positions <3.2%). Due to its special characteristics, such as isothermal operation, compact size, the MCC setup is suitable to be installed inside the instrument and the overall retention time for a complete spectrum is only a few minutes: this allows near real-time measurements in the optional MCC mode. In contrast to other methods that yield additional separation, such as the use of pre-cursor ions other than H3O(+), this method yields additional information without increasing complexity.</p>
[Cappellin2013a] "Multiclass methods in the analysis of metabolomic datasets: The example of raspberry cultivar volatile compounds detected by GC-MS and PTR-MS",
Food Research International
: Elsevier, 2013.
Multiclass sample classification and marker selection are cutting-edge problems in metabolomics. In the present study we address the classification of 14 raspberry cultivars having different levels of gray mold (Botrytis cinerea) susceptibility. We characterized raspberry cultivars by two headspace analysis methods, namely solid-phase microextraction/gas chromatography–mass spectrometry (SPME/GC–MS) and proton transfer reaction-mass spectrometry (PTR-MS). Given the high number of classes, advanced data mining methods are necessary. Random Forest (RF), Penalized Discriminant Analysis (PDA), Discriminant Partial Least Squares (dPLS) and Support Vector Machine (SVM) have been employed for cultivar classification and Random Forest-Recursive Feature Elimination (RF-RFE) has been used to perform feature selection. In particular the most important GC–MS and PTR-MS variables related to gray mold susceptibility of the selected raspberry cultivars have been investigated. Moving from GC–MS profiling to the more rapid and less invasive PTR-MS fingerprinting leads to a cultivar characterization which is still related to the corresponding Botrytis susceptibility level and therefore marker identification is still possible.
[Holopainen2013] "Multitrophic signalling in polluted atmospheres",
Biology, controls and models of tree volatile organic compound emissions
: Springer, pp. 285–314, 2013.
Volatile compounds emitted by plants in response to herbivory serve as important cues within and between trophic levels, and as cues over more than two trophic levels, such as in the attraction of enemies of herbivores. However, many of the volatiles elicited by herbivory are highly reactive with key atmospheric pollutants, implying that the signal is communicated over increasingly shorter distances with increasing pollutant concentrations in the atmosphere. Thus, polluted atmospheres can importantly alter the multitrophic interactions between trees, herbivores and herbivore enemies. This chapter highlights the alterations in multitrophic interactions and resulting modifications in plant fitness in polluted atmospheres.