Similar Volatile Organic Compounds Research Articles

Sansevieria trifasciata's specific metabolite improves tolerance and efficiency for particulate matter and volatile organic compound removal

Phytoremediation has become famous for removing particulate matter (PM) and volatile organic compounds (VOCs), but the ability is affected by plant health. Lately, the priming technique was a simple approach to studying improving plant tolerance against abiotic stress by specific metabolites that accumulated, known as “memory”, but the mechanism underlying this mechanism and how long this “memory” was retained in the plant was a lack of study. Sansevieria trifasciata was primed for one week for PM and VOC stress to improve plant efficiency on PM and VOC. After that, the plant was recovered for two- or five-weeks, then re-exposed to the same stress with similar PM and VOC concentrations from cigarette smoke. Primed S. trifasciata showed improved removal of PMs entirely within 2 h and VOC within 24 h. The primed plant can maintain a malondialdehyde (MDA) level and retain the “memory” for two weeks. Metabolomics analysis showed that an ornithine-related compound was accumulated as a responsive metabolite under exposure to PM and VOC stress. Exogenous ornithine can maintain plant efficiency and prevent stress by increasing proline and antioxidant enzymes. This study is the first to demonstrate plant “memory” mechanisms under PM and VOC stress.

Identification of exhaled volatile organic compounds that characterize asthma phenotypes: A J-VOCSA study

BackgroundAsthma is characterized by phenotypes of different clinical, demographic, and pathological characteristics. Identifying the profile of exhaled volatile organic compounds (VOCs) in asthma phenotypes may facilitate establishing biomarkers and understanding asthma background pathogenesis. This study aimed to identify exhaled VOCs that characterize severe asthma phenotypes among patients with asthma. MethodsThis was a multicenter cross-sectional study of patients with severe asthma in Japan. Clinical data were obtained from medical records, and questionnaires were collected. Exhaled breath was sampled and subjected to thermal desorption gas chromatography-mass spectrometry (GC/MS). ResultsUsing the decision tree established in the previous nationwide asthma cohort study, 245 patients with asthma were divided into five phenotypes and subjected to exhaled VOC analysis with 50 healthy controls (HCs). GC/MS detected 243 VOCs in exhaled breath samples, and 142 frequently detected VOCs (50% of all samples) were used for statistical analyses. Cluster analysis assigning the groups with similar VOC profile patterns showed the highest similarities between phenotypes 3 and 4 (early-onset asthma phenotypes), followed by the similarities between phenotypes 1 and 2 (late-onset asthma phenotypes). Comparisons between phenotypes 1–5 and HC revealed 19 VOCs, in which only methanesulfonic anhydride showed p < 0.05 adjusted by false discovery rate (FDR). Comparison of these phenotypes yielded several VOCs showing different trends (p < 0.05); however, no VOCs showed p < 0.05 adjusted by FDR. ConclusionsExhaled VOC profiles may be useful for distinguishing asthma and asthma phenotypes; however, these findings need to be validated, and their pathological roles should be clarified.

Effect of direct addition of asphalt rubber pellets on mixing, performance and VOCs of asphalt mixtures

Direct injection modifiers revealed vast development potential because of their convenience utilization and no need for professional equipment. However, different characteristics of each direct injection modifier fluctuate significantly on the mixing process and road performance of their modified asphalt mixtures. The purpose of this paper is to evaluate the effectiveness of two novel asphalt rubber pellets (ARP) and asphalt desulfurized rubber pellets (ADRP) in improving the performance of asphalt mixtures. Firstly, this paper used orthogonal experimental design method to determine the priority order of the influencing factors on direct injection modifiers (ARP and ADRP), and further optimized the mixing technology of asphalt mixtures containing direct injection modifiers. Then, using base asphalt, commercial asphalt rubber (AR) and SBS (styrene-butadiene-styrene block copolymer) modified asphalt as control groups, the road performance of five asphalt mixtures was evaluated. Finally, the volatile organic compounds (VOCs) release characteristics of the asphalt mixtures were quantitatively analyzed. The results indicated that the priority order of factors affecting the ARP and ADRP is digestion time > dry mixing time > mixing temperature, and the optimal mixing process parameters are dry mixing for 90 s, mixing temperature of 180 °C, and digestion time of 90 min. Additionally, road performance of ADRP modified asphalt mixtures (ADRP-AM) is superior to that of ARP modified asphalt mixture (ARP-AM), which reaches or even exceeds the road performance of asphalt rubber mixtures (AR-AM) and SBS modified asphalt mixtures (SBS-AM) prepared by wet process. The five asphalt mixtures demonstrate the similar VOCs composition, and the total concentration of VOCs emissions is ARP-AM > AR-AM > ADRP-AM > B-AM > SBS-AM. P-/m-xylene, acetone, benzene, ethylbenzene and substances containing chlorine emerge high concentration for the VOCs composition of the five asphalt mixtures. This research can provide technical support for promoting the widespread application of direct injection asphalt rubber pellets.

Solvent-induced fabrication of Cu/MnOx nanosheets with abundant oxygen vacancies for efficient and long-lasting photothermal catalytic degradation of humid toluene vapor

Construction of highly-active photothermal catalysts featuring merits of high quantum efficiency and superior heat resistance is a great challenge during volatile organic compounds (VOCs) degradation under high humidity. Herein, a facile solvent-induced dimensionality reduction strategy was proposed to engineer a nanosheeted and polycrystalline Cu/Mn-based catalyst (M-Cu/MnOx) having interfacial oxygen vacancies for enhanced photo-thermal catalytic degradation of toluene under highly humid conditions. Unique Cu-mediated δ-MnO2/Mn3O4 nanosheets with high surface area exhibited excellent light absorptivity and photogenerated carrier separation efficiency, as well as superior light-driven thermogenesis. It realized ultra-high (92.8%) toluene conversion and deep mineralization (84.4%) under RH = 80% and continuous catalytic reaction (200 h). Its toluene degradation rate exhibited 3.5–71.9 times higher than reported state-of-the-art photothermal catalysts. The newly designed M-Cu/MnOx catalyst provides a promising, low-cost and alternative for the efficient degradation of toluene and other similar VOCs under humid conditions on large-scale operations.

Profiling of volatile and non-volatile compounds in Dianhong by a combined approach of static headspace GC-MS and UPLC-MS

ABSTRACT The systematic identification of volatile organic compounds (VOCs) and non-VOCs will facilitate understanding the characteristic aroma and bioactive constituents of Dianhong. This article reported for the first time the volatile and non-volatile composition profiles of Dianhong from four main producing areas. A combined total of 42 VOCs were identified from four Dianhong samples by static headspace GC-MS. Thirteen VOCs were found to be important common components contributing to the characteristic aroma of Dianhong. The non-VOCs of Dianhong were evaluated by UPLC-ESI-MS, and Dianhong samples from four producing areas shared almost the same component profiles. Thirty-four components including derivatives of quinic acid, gallic acid, and catechin, flavone C-glycosides, flavonol O-glycosides, and alkaloids were characterized. Finally, catechin, gallic acid, 5-O-galloylquininc acid, and theobromine were characterized as the main non-VOCs in Dianhong. Dianhong samples from four main producing areas showed similar VOCs and non-VOCs profiles under our optimized GC-MS and LC-MS conditions.

Preservation of high pressure pasteurised milk by hyperbaric storage at room temperature versus refrigeration on inoculated microorganisms, fatty acids, volatile compounds and lipid oxidation

High pressure pasteurised (HPP) milk was stored by hyperbaric storage at room temperature (HS/RT) (50–100 MPa at 20 °C) and compared with refrigeration (RF), to assess the effect on two pathogens surrogates and a pathogenic, up to 120 days, and on fatty acids, volatile organic compounds (VOCs) and secondary lipid oxidation over 60 days.HS/RT (75–100 MPa) was able to inactivate at least 6.68/6.31/6.03 log CFU/mL of Escherichia coli/Listeria innocua/Salmonella Senftenberg (to below the detection limit), while RF resulted only in minor changes. Overall, fatty acids profile remained stable under HS/RT, although secondary lipid oxidation showed slightly higher values. In addition, both HS/RT and RF showed stable and similar VOCs profiles and off-flavour indicative compounds were not detected, except for the lowest pressure (50 MPa) after 40 days.HS/RT preserved HPP milk with enhanced microbial safety, shelf-life and quality compared to RF, being in addition quasi-energetically costless and more sustainable than RF.

Profiling of Volatile Organic Compounds in Wild Indigenous Medicinal Ginger (Zingiber barbatum Wall.) from Myanmar.

The emissions of volatile organic compounds (VOCs) strongly depend on the plant species and are differently represented in specific taxa. VOCs have a degree of chemical diversity and also can serve as chemotaxonomic markers. Zingiber barbatum Wall. is a wild medicinal ginger plant endemic to Myanmar whose VOC composition has never been screened before. In this study, we screened the rhizome of Z. barbatum to identify the VOC composition by the application of gas chromatography combined with time-of-flight-mass spectrometry (GC-TOF-MS). The resulting VOC profile of Z. barbatum showed that it consists mainly of monoterpenes (21%) and sesquiterpenes (30%). Intraspecific similarities and dissimilarities were found to exist between Z. barbatum genotypes in terms of VOC composition. Four accessions (ZO191, ZO223, ZO217, and the control accession ZO105) collected from the Shan State and Mandalay region of Myanmar were found to share a similar VOC profile, while two accessions (ZO64 and ZO160) collected from the Bago region were found to vary in their VOC profiles compared with the control accession. The two identified compounds, i.e., α-bergamotene and β-(E)-guaiene may serve as discriminative chemical markers for the characterization of Z. barbatum species collected in these three geographical regions of Myanmar. This study represents a first attempt to identify and describe the VOCs in the medicinal species Z. barbatum that have not been reported to date.

Assessment of pulmonary oxygen toxicity in special operations forces divers under operational circumstances using exhaled breath analysis.

The Netherlands Maritime Special Operations Forces use closed circuit oxygen rebreathers (O₂-CCR), which can cause pulmonary oxygen toxicity (POT). Recent studies demonstrated that volatile organic compounds (VOCs) can be used to detect POT in laboratory conditions. It is unclear if similar VOCs can be identified outside the laboratory. This study hypothesised that similar VOCs can be identified after O₂-CCR diving in operational settings. Scenario one: 4 h O₂-CCR dive to 3 metres' seawater (msw) with rested divers. Scenario two: 3 h O₂-CCR dive to 3 msw following a 5 day physically straining operational scenario. Exhaled breath samples were collected 30 min before and 30 min and 2 h after diving under field conditions and analysed using gas chromatography-mass spectrometry (GC-MS) to reconstruct VOCs, whose levels were tested longitudinally using a Kruskal-Wallis test. Eleven divers were included: four in scenario one and seven in scenario two. The 2 h post-dive sample could not be obtained in scenario two; therefore, 26 samples were collected. GC-MS analysis identified three relevant VOCs: cyclohexane, 2,4-dimethylhexane and 3-methylnonane. The intensities of 2,4-dimethylhexane and 3-methylnonane were significantly (P = 0.048 and P = 0.016, respectively) increased post-dive relative to baseline (range: 212-461%) in both scenarios. Cyclohexane was increased not significantly (P = 0.178) post-dive (range: 87-433%). VOCs similar to those associated with POT in laboratory conditions were identified after operational O₂-CCR dives using GC-MS. Post-dive intensities were higher than in previous studies, and it remains to be determined if this is attributable to different dive profiles, diving equipment or other environmental factors.

Profile Characteristics of VOCs from Wood and Economic Crop Burning

Wood and economic crops are still widely used in rural areas of China. Although their combustion is an important source of volatile organic compounds (VOCs), study on their emission characteristics is relatively weak. In this study, three kinds of wood (poplar, cedarwood, and citrus branches) and six economic crop straws (soybean stalk, sesame stalk, corn cob, cotton stalk, peanut stalk, and corn stalk) were selected and their burning was simulated in the laboratory. A dilution tunnel system was used to dilute the smoke, and then Tedlar bags were used to collect the smoke. The compositions of 102 VOCs were analyzed by Agilent 7820A/5977E gas chromatography/mass spectrometry. The ozone formation potential (OFP) of VOCs for different types of biomass burning was analyzed. The results indicated that there are differences in the VOC compositions of different types of biomass burning emissions. Ethane (11.1%), trans-2-pentene (15.4%), ethylene (8.3%), and dichloromethane (11.9%) are the main VOCs emitted from poplar and cedarwood burning. Toluene (49.8%) is the most abundant species of VOC emitted from burning of citrus branches. Ethylene (11.8%-17.5%) and acetone (9.2%-14.7%) are the main VOCs components of straw burning. Corn stalks, peanut stalks, and citrus branches have similar VOC source profiles, with the coefficient of divergence less than 0.1. The benzene/toluene ratio for biomass burning emissions obtained in this study and in the literature is in the range of 0.030-6.48. It is arguable that a value higher than 1 indicated the impact of biomass burning. The contributions of alkenens, oxygenated VOCs, and aromatic hydrocarbons to the OFP of biomass burning were 30.6%-80.3%, 6.5%-21.0%, and 3.8%-56.5%, respectively. The components contributing more than 10.0% to the OFP are ethylene, propylene, trans-2-pentene, cis-2-pentene, toluene, and propionaldehyde.

Relationship between cancer tissue derived and exhaled volatile organic compound from colorectal cancer patients. Preliminary results

New insight into the omic sciences suggests that volatile organic compounds (VOCs) contained in exhaled breath can reflect the healthy or disease state of patients, representing an attractive, promising and non-invasive method of medical investigation. This approach has recently been proposed as a new potential screening tool in colorectal cancer (CRC) patients. However, a possible correlation between the exhaled VOCs and those produced by the cancerous tissue has never been investigated. In this preliminary study, we compare the VOCs exhaled by seven patients affected by CRC with those produce by own cancer tissue and normal colonic mucosa.The VOCs contained in the exhaled breath were sampled with the ReCIVA breath sampler©, while those produced by ex-vivo human tissues weresampled by headspace solid-phase microextraction (HS-SPME) at different incubation times after surgery. In both cases, the collected VOCs were analyzed by Gas Chromatography with Mass Spectrometry (GC–MS).Benzaldehyde, benzene ethyl, benzene methyl, butanoic acid, dodecanoic acid, indole, nonanal, octanoic acid, pentanoic acid, phenol and tetradecane were the VOCs most frequently detected both in the exhaled breath and secreted by tissues.The results showed that cancer tissue and normal colonic mucosa from the same patient produced a similar VOCs pattern but with different fingerprints. In particular, the concentrations of benzaldehyde, benzene ethyl and indole were significantly different in cancer tissue respect the normal colonic mucosa.In conclusion, these preliminary data suggest the involvement of the three compounds in CRC by encouraging further investigation.

Floral volatiles structure plant–pollinator interactions in a diverse community across the growing season

Abstract While the importance of floral odours for pollinator attraction relative to visual cues is increasingly appreciated, how they structure community‐level plant–pollinator interactions is poorly understood. Elucidating the functional roles of flowering plant species with respect to their floral volatile organic compounds (VOCs) and how those roles vary over the growing season is an initial step towards understanding the contribution of floral VOCs to plant–pollinator interaction structure. We sampled the floral VOCs, phenologies and bee visitors of naturally growing plants in a montane meadow in the Northern Rocky Mountains of USA in order to acquire a base understanding of how floral VOCs and other plant traits may structure plant–pollinator interactions across the growing season. We expected forb species with floral VOCs that were original (far from the community mean) and unique (far from the nearest neighbour) would have few pollinating partners (i.e. specialists), while forbs with non‐original or highly variable floral VOCs would form the generalist core of interactors, thereby contributing to network nestedness (specialists interacting with nested subsets of generalists). Network modularity (patterns of distinct, highly connected subnetworks) could be influenced by groups of pollinators that are attracted to or repelled by certain floral bouquets. Species blooming in early spring emitted similar floral VOC blends containing generalist attractants, whereas floral VOC complexity was highest in mid to late summer. Forb species varied in the originality, uniqueness, and intraspecific variation (i.e. dispersion) of their floral VOCs, indicating the potential for different functional roles in plant–pollinator networks. Specifically, the originality, uniqueness and dispersion of forb species’ floral VOCs increased across the growing season. Floral VOCs influenced forb interactions with pollinators. Floral VOCs contributed to the nested structure, but not modular structure, of community‐level plant–pollinator network structure. Forb species with more original floral VOCs were less connected, while forb species emitting more compounds and with higher intraspecific variation in floral VOCs were more connected to pollinators. These findings show that floral scent plays important roles in structuring bee–forb interactions and guiding seasonal patterns in complex communities. Understanding seasonal patterns in floral VOCs may have important implications for plant–pollinator interactions among communities differing in species composition, or as shifts occur in suites of co‐flowering species due to climate change. A free Plain Language Summary can be found within the Supporting Information of this article.

Development of Fast E-nose System for Early-Stage Diagnosis of Aphid-Stressed Tomato Plants.

An electronic nose (E-nose) system equipped with a sensitive sensor array was developed for fast diagnosis of aphid infestation on greenhouse tomato plants at early stages. Volatile organic compounds (VOCs) emitted by tomato plants with and without aphid attacks were detected using both the developed E-nose system and gas chromatography mass spectrometry (GC-MS), respectively. Sensor performance, with fast sensor responses and high sensitivity, were observed using the E-nose system. A principle component analysis (PCA) indicated accurate diagnosis of aphid-stressed plants compared to healthy ones, with the first two PCs accounting for 86.7% of the classification. The changes in VOCs profiles of the healthy and infested tomato plants were quantitatively determined by GC-MS. Results indicated that a group of new VOCs biomarkers (linalool, carveol, and nonane (2,2,4,4,6,8,8-heptamethyl-)) played a role in providing information on the infestation on the tomato plants. More importantly, the variation in the concentration of sesquiterpene VOCs (e.g., caryophyllene) and new terpene alcohol compounds was closely associated with the sensor responses during E-nose testing, which verified the reliability and accuracy of the developed E-nose system. Tomato plants growing in spring had similar VOCs profiles as those of winter plants, except several terpenes released from spring plants that had a slightly higher intensity.

Markers of Pulmonary Oxygen Toxicity in Hyperbaric Oxygen Therapy Using Exhaled Breath Analysis.

IntroductionAlthough hyperbaric oxygen therapy (HBOT) has beneficial effects, some patients experience fatigue and pulmonary complaints after several sessions. The current limits of hyperbaric oxygen exposure to prevent pulmonary oxygen toxicity (POT) are based on pulmonary function tests (PFT), but the limitations of PFT are recognized worldwide. However, no newer modalities to detect POT have been established. Exhaled breath analysis in divers have shown volatile organic compounds (VOCs) of inflammation and methyl alkanes. This study hypothesized that similar VOCs might be detected after HBOT.MethodsTen healthy volunteers of the Royal Netherlands Navy underwent six HBOT sessions (95 min at 253 kPa, including three 5-min “air breaks”), i.e., on five consecutive days followed by another session after 2 days of rest. At 30 min before the dive, and at 30 min, 2 and 4 h post-dive, exhaled breath was collected and followed by PFT. Exhaled breath samples were analyzed using gas chromatography-mass spectrometry (GC-MS). After univariate tests and correlation of retention times, ion fragments could be identified using a reference database. Using these fragments VOCs could be reconstructed, which were clustered using principal component analysis. These clusters were tested longitudinally with ANOVA.ResultsAfter GC-MS analysis, eleven relevant VOCs were identified which could be clustered into two principal components (PC). PC1 consisted of VOCs associated with inflammation and showed no significant change over time. The intensities of PC2, consisting of methyl alkanes, showed a significant decrease (p = 0.001) after the first HBOT session to 50.8%, remained decreased during the subsequent days (mean 82%), and decreased even further after 2 days of rest to 58% (compared to baseline). PFT remained virtually unchanged.DiscussionAlthough similar VOCs were found when compared to diving, the decrease of methyl alkanes (PC2) is in contrast to the increase seen in divers. It is unknown why emission of methyl alkanes (which could originate from the phosphatidylcholine membrane in the alveoli) are reduced after HBOT. This suggests that HBOT might not be as damaging to the pulmonary tract as previously assumed. Future research on POT should focus on the identified VOCs (inflammation and methyl alkanes).

Comparison of two commercial solid‐phase microextraction fibers for the headspace analysis of volatile compounds in different pork and beef cuts

The performance of carboxen/polydimethylsiloxane (Car/PDMS) and divinylbenzene/Car/PDMS (DVB/Car/PDMS) fibers in extracting volatile organic compounds (VOCs) from different pork and beef cuts by headspace solid-phase microextraction (HS-SPME) was compared. A principal component analysis (PCA), cluster analysis (CA), and an analysis of variance were employed subsequently to evaluate the extraction performance. DVB/Car/PDMS fibers exhibited similar VOC profiles, but were less effective than Car/PDMS fibers which showed significantly (p < 0.05) higher extraction yields of major volatile groups including acids, alcohols, aldehydes, amines, and ketones in most of the tested meat cuts. There were no significant (p > 0.05) differences in the amount of aliphatic hydrocarbon, aromatic hydrocarbon, esters, and sulfur compounds extracted by both fibers. Car/PDMS exhibited significant (p < 0.05) differences in the amount of VOCs extracted from different meat cuts, while DVB/Car/PDMS fiber did not. These findings might provide insights into HS-SPME of VOCs from different meat cuts. Practical applications The application of HS-SPME for the determination of VOCs in raw or processed meats, particularly pork and beef cuts, has been extensively studied in recent years. Among the commercial SPME fibers available, Car/PDMS and DVB/Car/PDMS fibers are the most frequently employed. However, no adequate information regarding the selection process and comparison of the fibers has been provided. The results of this study demonstrate that the profile of VOCs in different cuts of pork and beef was strongly influenced by the type of fiber used for extraction. Thus, these findings might provide new insights into the HS-SPME analysis of VOCs in different meat cuts, especially the selection of fibers for the extraction of specific VOC analytes.

Emissions of Volatile Organic Compounds from road marking paints

Regulations, definitions, and calculations related to emissions of Volatile Organic Compounds (VOC) from paints used for horizontal road markings (traffic paints) in North America and in European Union are different, which frequently makes simple comparisons impossible. To illustrate the dissimilarities, solvent packages of various exemplary paints that meet several normative requirements were compared for the nominal emissions according to different calculation procedures. For a unified assessment, volatile portions of the paints were evaluated based on Ozone Formation Potential (OFP). The analysis revealed that similar nominal VOC contents can lead to vastly different OFP, in an extreme case six times higher. Incongruously high OFP, which was calculated for emissions in Southern California despite strict limits can thus be explained. The provided calculations can be used by road administrators as a tool to demand materials with lowest environmental impact, by environmental researchers to pinpoint irregularities between declared and measured discharges, and can assist formulating chemists in selection of raw materials to prepare environmentally friendly road marking paints.

Chemically mediated species recognition in two sympatric Grayling butterflies: Hipparchia fagi and Hipparchia hermione (Lepidoptera: Nymphalidae, Satyrinae)

Pheromones are known to play an important role in butterfly courtship and may influence both individual reproductive success and reproductive isolation between species. Recent studies have focused on courtship in Hipparchia butterflies (Nymphalidae: Satyrinae) emphasizing morphological and behavioural traits, as well as genetic differences. Behavioural observations suggested a role for chemical cues in mate and species recognition, where the androconial scales on the forewings of these species may be involved in chemical communication between individuals. Cchemical-mediated signals have received relatively little attention in this genus. Here, we report the results of a three-year investigation of the volatile organic compounds (VOCs) released by Hipparchia fagi and H. hermione in order to identify differences in VOCs between these species where they live in syntopy. Our study was carried out using an array of cross-selective sensors known as an "Electronic Nose" (EN) that operates by converting chemical patterns into patterns of sensor signals. While the identity of volatile compounds remained unknown, sensor signals can be compared to identify similar or dissimilar chemical patterns. Based on the EN signals, our results showed that: 1) the two sexes have a similar VOCs pattern in H. fagi, while they significantly diverge in H. hermione; 2) VOCs patterns were different between females of the two species, while those of males were not.

Vacuum Ultraviolet Spectroscopy and Mass Spectrometry: A Tandem Detection Approach for Improved Identification of Gas Chromatography-Eluting Compounds.

For wide class characterizations of volatile organic compounds (VOCs), conventional gas chromatography mass spectrometry (GC-MS)-based techniques are utilized. These GC-MS-based chemical identification approaches typically rely on library searches against ion fragmentation patterns of known compounds. Although MS library searches can often provide correct chemical identities, erroneous chemical assignments of structurally similar unknown compounds are also possible. Other detection systems, such as absorption spectrometers, have been used for VOC analysis and can provide complementary absorption data. Here, we demonstrate the analytical advantages of coupling vacuum ultraviolet (VUV) absorption spectroscopy and MS in tandem for the improved characterization of structurally similar VOCs. We also discuss technical considerations and limitations of coupling a VUV spectrometer to a quadrupole mass spectrometer. Moreover, we show that combining the isomer selectivity of VUV spectroscopy, as a nondestructive analyte detection approach, with the mass selectivity of MS in a VUV-MS detection system improves characterization of GC-eluting compounds. Utilizing GC/VUV-MS data, we demonstrate that orthogonal VUV and MS library searches improve identification of VOCs present in complex mixtures such as a mixed standard sample, a commercial perfume product, and an essential oil sample.

Odour of King Penguin feathers analysed using direct thermal desorption discriminates between individuals but not sexes

The role and use of olfactory cues by penguins is largely under‐investigated, with only a few studies suggesting that odours are involved in prey detection, orientation and for interspecific communication. This also applies to King Penguins Aptenodytes patagonicus where little is known about their chemoreception abilities and, subsequently, the role of odours in their behavioural ecology. Here, we investigated the chemical composition of volatile organic compounds (VOCs) from feathers of King Penguins in the Kerguelen Archipelago and their potential to carry information on identity and sex. We analysed VOCs using direct thermal desorption, a novel approach for extracting volatile compounds directly from solid matrices. We were only able to test at desorption temperatures of 70 and 100 °C to optimize conditions for VOC analysis. We found a profile of 26 VOCs present in most individuals, which varied significantly between individuals but not between sexes. Results suggested that VOCs could possibly be used by King Penguins to locate the colony and recognize individuals, if similar VOCs are also present at ambient conditions. Further studies and behavioural experiments are encouraged to explore olfactory‐based communication in this species.

Investigation of cell culture volatilomes using solid phase micro extraction: Options and pitfalls exemplified with adenocarcinoma cell lines.

Three strategies to sample volatile organic compounds (VOC) from lung cancer cell lines cultured in vitro were compared. Headspace solid phase microextraction was applied in situ to culture flasks and alternatively to subsamples of headspace gas or to nutrient solution subsamples followed by gas chromatography-mass spectrometry. The direct quantification of 55 VOC in the headspace of cell cultures was validated and is discussed with respect to reproducibility and system-related interferences. The role of the VOC background from culture media and usually employed polystyrene culture vessels is examined and was seen to invoke potentially misleading conclusions. The commercial A549 and two further adenocarcinoma cell lines displayed largely similar VOC profiles with distinct differences regarding certain individual substances. There is evidence for the inappropriateness of the standard cell culturing methods in the search for volatile cancer markers.

Carotta: Revealing Hidden Confounder Markers in Metabolic Breath Profiles.

Computational breath analysis is a growing research area aiming at identifying volatile organic compounds (VOCs) in human breath to assist medical diagnostics of the next generation. While inexpensive and non-invasive bioanalytical technologies for metabolite detection in exhaled air and bacterial/fungal vapor exist and the first studies on the power of supervised machine learning methods for profiling of the resulting data were conducted, we lack methods to extract hidden data features emerging from confounding factors. Here, we present Carotta, a new cluster analysis framework dedicated to uncovering such hidden substructures by sophisticated unsupervised statistical learning methods. We study the power of transitivity clustering and hierarchical clustering to identify groups of VOCs with similar expression behavior over most patient breath samples and/or groups of patients with a similar VOC intensity pattern. This enables the discovery of dependencies between metabolites. On the one hand, this allows us to eliminate the effect of potential confounding factors hindering disease classification, such as smoking. On the other hand, we may also identify VOCs associated with disease subtypes or concomitant diseases. Carotta is an open source software with an intuitive graphical user interface promoting data handling, analysis and visualization. The back-end is designed to be modular, allowing for easy extensions with plugins in the future, such as new clustering methods and statistics. It does not require much prior knowledge or technical skills to operate. We demonstrate its power and applicability by means of one artificial dataset. We also apply Carotta exemplarily to a real-world example dataset on chronic obstructive pulmonary disease (COPD). While the artificial data are utilized as a proof of concept, we will demonstrate how Carotta finds candidate markers in our real dataset associated with confounders rather than the primary disease (COPD) and bronchial carcinoma (BC). Carotta is publicly available at http://carotta.compbio.sdu.dk [1].