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The remarkable species richness of the Neotropical aroid genus Philodendron (Araceae) is closely linked to its specialized nocturnal pollination system, where chemically distinct floral scents selectively attract night-active cyclocephaline beetles (Melolonthidae, Cyclocephalini). This study explores the floral biology and chemical ecology of Philodendron cipoense, an endangered, rupicolous species endemic to Brazil’s Espinhaço mountain range in the Campo Rupestre. Through qualitative and quantitative analyses of floral scent chemistry and field experiments, we assessed the role of key volatile organic compounds (VOCs) in pollinator attraction. P. cipoense relies heavily on pollinators and attracted a diverse assemblage of specialized beetles, including Cyclocephala atricapilla, C. variolosa, Chalepides dilatatus, and Erioscelis sp. Its floral scent is dominated by (Z)-jasmone, 4-vinylanisole, and isojasmol, collectively accounting for 97% of total emissions. Field experiments confirmed the attractiveness of (Z)-jasmone, successfully luring a male of C. atricapilla (pollinator) and C. celata (non-pollinator) individuals of both sexes. These findings underscore the pivotal role of floral scent as an olfactory cue in pollinator attraction, revealing asymmetrical mutualisms and interdependence between P. cipoense and its pollinators. Our results provide valuable insights for conservation strategies and targeted action plans to protect this threatened species. [ABSTRACT FROM AUTHOR]

Scirpophaga incertulas Walker (Lepidoptera: Crambidae, yellow stem borer, YSB) is a monophagous insect pest that causes significant yield loss in rice (Oryza staiva L.). Semiochemical based pest management is being sought as an alternate to chemical pesticides to reduce pesticide footprints. We hypothesized differential release of volatiles from host rice and two companion non-host weeds, Echinochloa colona and Echinochloa crus-galli could be responsible for oviposition and biology of YSB and these chemicals could be used for YSB management. Number of eggs laid, and number of larvae hatched were significantly higher in rice plant as compared to weeds. YSB could only form dead hearts in rice plants. YSB significantly preferred host-plant volatiles compared to the non-host plants both in choice and no-choice tests in an Y-tube olfactometer. 2-Hexenal, hexanal, 2,4-hexadienal, benzaldehyde, nonanal, methyl salicylate and decanal were found in the leaf volatolomes of both the host and non-host plants in HS-SPME-GC-MS (Headspace-Solid phase micro extraction-Gas chromatography-Mass spectrometer). Pentene-3-one, 2-pentyl furan, 2,4-heptadienal, 2-octenal, 2-octenol and menthol were present only in the non-host plants. Fourteen rice unique compounds were also detected. The built-in PCA (Principal Component Analysis) and PLS-DA (Partial least squares-discriminant analysis) analysis in the MS-DIAL tool showed that the volatiles emitted from TN1 formed a cluster distinct from Echinochloa spp. and 2-octenal was identified as a unique compound. Olfactometer bioassays using synthetic compounds showed that rice unique compounds, like xylene, hexanal served as attractants whereas non-host unique compounds, like 2-pentylfuran, 2-octenal acted as repellent. The results indicate that the rice unique compounds xylene, hexanal along with other volatile compounds could be responsible for higher preference of YSB towards rice plants. Similarly, the non-host unique compounds 2-pentylfuran, 2-octenal could possibly be responsible for lower preference and defence against YSB. These compounds could be utilised for devising traps for YSB monitoring and management. [ABSTRACT FROM AUTHOR]

Spathiphyllum is a mostly Neotropical genus of the Araceae plant family. Many species have a long flowering period and emit a strong, pleasant, and species‐specific floral scent. In Mexico, Spathiphyllum is represented by 14 species, 9 of which are endemic. Here, we describe the morphology, floral scent composition, and flowering phenology of a hitherto unknown species, S. hentrichianum sp. nov. This species is characterized by having a petiole not sheathed to the geniculum, leaf blades with less than 25 primary lateral veins per side, 1–2 ovules per locule, and 3–5 ovules per ovary. The strong scent consists of various terpenes and aromatic compounds, mainly (E,E)‐α‐Farnesene, (E)‐Cinnamyl acetate and (E)‐Cinnamyl alcohol. The new species is morphologically similar to S. cochlearispathum, but the latter differs in having a petiole sheathed to the geniculum, leaf blades with up to 31 primary lateral veins per side, 2–6 ovules per locule and 6–16 ovules per ovary, and the floral scent is also different between both species. In S. cochlearispathum, the scent is dominated by aromatic compounds, one terpene and one nitrogen‐containing compound, such as Methyl salicylate, Methyl p‐anisate, Methyl (E)‐cinnamate, (R)‐Linalool and 2‐Phenylacetonitrile. The flowering cycle of an inflorescence in S. hentrichianum lasted between 25 and 29 days. We suggest that detailed volatile organic compounds in the floral scent could be useful when defining a new taxon, especially among cryptic and sympatric aroid species. [ABSTRACT FROM AUTHOR]

The volatile composition and odor of meat and meat products is based on the precursors present in the raw meat. These are influenced by various pre-slaughter factors (species, breed, sex, age, feed, muscle type). Furthermore, post-mortem conditions (chiller aging, cooking conditions, curing, fermentation, etc.) determine the development of meat volatile organic compounds (VOCs). In this review, the main reactions leading to the development of meat VOCs such as the Maillard reaction; Strecker degradation; lipid oxidation; and thiamine, carbohydrate, and nucleotide degradation are described. The important pre-slaughter factors and post-mortem conditions influencing meat VOCs are discussed. Finally, the pros, cons, and future perspectives of the most commonly used sample preparation techniques (solid-phase microextraction, stir bar sorptive extraction, dynamic headspace extraction) and analytical methods (gas chromatography mass spectrometry and olfactometry, as well as electronic noses) for the analysis of meat VOCs are discussed, and the continued importance of sensorial analysis is pinpointed. [ABSTRACT FROM AUTHOR]

A method based on dynamic headspace vacuum transfer in trap extraction, followed by gas chromatography coupled with a mass spectrometer (DHS-VTT-GC-MS), was validated for the fast quantitation of 1,4-dichlorobenzene (p-dichlorobenzene; PDCB) and thymol residues in beeswax. The quantitation limits (LOQ) were 0.05 mg/kg (PDCB) and 0.25 mg/kg (thymol). Recoveries above 80% were obtained for PDCB concentrations between 0.05 and 10 mg/kg and for thymol concentrations between 0.25 and 200 mg/kg. Analysis of beeswax samples showed a good correlation between the results obtained by DHS-VTT-GC-MS analysis and those of a previous method based on SPE extraction followed by gas chromatography and triple- quadrupole mass spectrometry (GC-MS/MS) (R2 = 0.9770 for PDCB and 0.9666 for thymol). However, the sample preparation and chromatography were much shorter using the DHS-VTT-GC-MS method. Forty comb foundations samples produced in Switzerland in 2019 and 2021 were analysed using DHS-VTT-GC-MS. Fourteen samples contained PDCB above the LOQ of 0.05 mg/kg, ranging up to a maximum of 1.53 mg/kg. The mean concentration of the positive samples was 0.22 mg/kg. All samples contained thymol residues ranging between 3.9 and 84.4 mg/kg with mean and median concentrations of 22.7 mg/kg and 17.4 mg/kg. Residue levels of PCDB and thymol in Swiss beeswax were substantially below those measured 20 (PDCB) and 10 (thymol) years ago, respectively. [ABSTRACT FROM AUTHOR]

Detection and interpretation of chemical cues is essential for Varroa destructor Anderson and Trueman, an important parasite of honey bees (Apis mellifera L.), to complete its life cycle. We collected volatiles from honey bee brood at various developmental stages and screened for V. destructor electrophysiological responses to these with gas chromatography-linked electrotarsal detection. Volatile collections contained several methyl-alkanes that evoked electrophysiological responses from V. destructor. Moreover, odors in honey bee colonies that regulate honey bee colony structure and function were also detected by V. destructor. Collections from mid- to late-stage larvae had detectable levels of low-volatility odors identified as components of the honey bee brood pheromone and branched alkanes likely originating from brood cuticle. Among these, several mid- to heavy-molecular weight compounds elicited high proportional electrophysiological responses by V. destructor relative to their abundance but could not be identified using chemical standards of previously documented honey bee brood odors. We suggest further investigation of these unknown volatiles and future behavioral assays to determine attractiveness/repellency (valence) of those identified through chemical standards. [ABSTRACT FROM AUTHOR]

In this study, Tombul type hazelnuts (Corylus avellana L.) were extracted by supercritical carbondioxide (SCCO2) extraction and maceration method. The extraction yielded in 8.5% by SC-CO2 extraction when 0.84% by maceration. Extracted hazelnuts were analyzed by Dynamic Headspace Analysis/Gas Chromatography-Mass Spectrometry and 24 volatile compounds were detected after SC-CO2 method while 41 compounds were detected after maceration. Flavour and antioxidant value preserved Hazelnut extract by SC-CO2 technique showed better radical scavenging ability in 2,2-Diphenyl-1-picrylhydrazyl (DPPH) than the one by maceration. Antioxidant activities of the extracts obtained by SC-CO2 (12.35±0.06 μg/mL) and by maceration (8.79±0.23 μg/mL) had a medium impact compared with the synthetic antioxidant standards (P< 0.05). No significant difference was observed between the total phenolic contents of the hazelnut extracts obtained by SC-CO2 method and by maceration (P < 0.05). As a result, SC-CO2 technique for extraction of Tombul type hazelnuts was concluded to be more beneficial and suitable compared to maceration technique. [ABSTRACT FROM AUTHOR]

In this study, optimum process parameters for supercritical carbon dioxide (CO2) (SC-CO2) extraction of roasted pistachio (Pistacia vera L.) were investigated by depending on amount of the characteristic flavouring components (α-pinene, limonene-D, α-terpinolene and β-myrcene). The extracts were analysed by DHA/GC-MS for determination of the volatile compounds and the optimum process parameters were decided as 200 g, 350 Bar, 70°C, 75 g CO2/min and 60 min. In the pistachio extracts obtained having the optimum process parameters, α-pinene, β-myrcene, limonene-D and α-terpinolene were detected as 24.47 g/100 g, 0.52 g/100 g, 2.25 g/100 g and 5.70 g/100 g among 31 volatile compounds in total, respectively. The fatty acid composition of the extract, which had the most desirable taste and flavour, was detected by gas chromatography using fatty acid methyl esters (FAME) preparation. The fatty acid composition analysis showed that the pistachio extract had included mostly oleic acid (67.51%, w/w) and linoleic acid (17.85%, w/w).

Usually considered anemophilous, grasses (Poaceae) have been the subject of few studies that recorded insects visiting their flowers. Such visitors, with wind, could act as pollen vectors in a possible ambophilous system. Since colour and scent are floral cues attracting pollinating insects, we aimed to provide the first insights into how these cues could be involved in the attraction of pollinators by grasses. Chloris barbata, Paspalum maritimum (with two morphotypes), P. millegrana and Urochloa plantaginea were studied. We determined the role of each pollen vector (wind and insect) and we registered the frequency of floral visitors. Also, we characterized the colour reflectance of glumes, anthers and stigmas and we determined the colour space in the bee colour hexagon and the chemical composition of floral scents. The floral structures of each species reflect colour differently and are perceived differently by pollinators. Furthermore, the volatile organic compounds detected are similar to those found in entomophilous species. In two of the grass species, we registered eight species of visitors, including bees, wasps and flies. Overall, wind was the most important vector for reproductive success. Insects, however, may induce wind pollination by creating pollen clouds when they visit inflorescences. [ABSTRACT FROM AUTHOR]

The development of sample preparation procedures is still a dynamic process despite a number of already proposed techniques. The main challenge in this research field is to fully replace classical procedures like liquid‐liquid extraction and solid‐phase extraction in gas chromatographic analysis. Some progress has been already achieved for the last 20 years when miniaturized techniques were incorporated in ISO standards. The current review is focused on novel approaches in sample treatment that appeared since 2010. It includes research studies describing non‐conventional instrumental design available to inspire future progress in the field. A combination of a few extraction principles and supporting with additional treatment are the main core suggested for improvement of sample preparation efficiency. This requires good compatibility of extraction media, assessment of multiple experimental parameters, and potential automatization possibilities. [ABSTRACT FROM AUTHOR]

• Yak milk is rich in flavor components and is mostly in trace levels. • DHS method allowed a green, high throughput and efficient sample extraction. • Analytical method was developed and validated by chemometrics. • An external standard provided more accurate quantitative. • The CAR/PDMS/DVB material provided the best extraction of volatiles from yak milk. A dynamic headspace (DHS) with DVB/CAR/PDMS trapping materials was coupled to a gas chromatography-mass spectrometry for the separation and identification of volatile-flavor compounds in bos grunniens (yak) milk. The principal components analysis coupled with response surface methodology optimized the main variables of the device (10 g sample quality, 5 min desorption time, 3.0 g adding sodium chloride, 72 °C extraction temperature, 28 min pre-equilibrium time and 86 min extraction time). Total 235 volatile components were identified. The limit of detections and quantifications of volatile components were 0.01–5.35 mg kg−1 and 0.01–9.41 mg kg−1, respectively, with relative standard deviation from 0.2% to 6.4%. The method performed well during volatile-flavor components analysis from the yak milk sample, producing excellent extraction parameters for the volatile components. Eighty-two volatile components identified in yak milk belonged to a broad range of chemical classes (ketones, aldehydes, aromatics, acids, alkanes, and estes), and 73 of them were at trace levels. Meanwhile, using gas chromatography-olfactometry technique, 11 volatile components were identified as contributors to the aroma of yak milk. In conclusions, a sensitive, convenient and reliable method was developed for the accurate determination of volatile-flavor compounds in yak milk utilizing DHS-GC/MS analyses. [ABSTRACT FROM AUTHOR]

Highlights • DMTS is a promising next-generation cyanide antidote. • It requires small blood volumes (50 μL) and can detect 0.04 μM (LOD) of DMTS. • The sample preparation is fast (10 min), simple, and economical. • Impressive pharmacokinetic behavior of DMTS was demonstrated in rats. • The method presented should be considered the "gold-standard" for DMTS analysis. Abstract Cyanide is a rapidly acting and highly toxic chemical. It inhibits cytochrome c oxidase in the mitochondrial electron transport chain, resulting in cellular hypoxia, cytotoxic anoxia and potentially death. In order to overcome challenges associated with current cyanide antidotes, dimethyl trisulfide (DMTS), which converts cyanide to less toxic thiocyanate in vivo , has gained much attention recently as a promising next-generation cyanide antidote. While there are three analysis methods available for DMTS, they each have significant disadvantages. Hence, in this study, a dynamic headspace (DHS) gas chromatography–mass spectroscopy method was developed for the analysis of DMTS from rabbit whole blood. The method is extremely simple, involving only acidification of a blood sample, addition of an internal standard (DMTS-d 6) and DHS-GC–MS analysis. The method produced a limit of detection of 0.04 μM for DMTS with dynamic range from 0.2 to 50 μM. Inter- and intraassay accuracy (100 ± 15% and 100 ± 9%, respectively), and precision (<10% and <9% relative standard deviation, respectively) were good. The validated method performed well during pharmacokinetic analysis of DMTS from the blood of rats treated with DMTS, producing excellent pharmacokinetic parameters for the treatment of cyanide exposure. The method produced significant advantages over current methods for analysis of DMTS and should be considered as a "gold standard" method for further development of DMTS as a potential next-generation cyanide countermeasure. [ABSTRACT FROM AUTHOR]

• Dynamic headspace sampling with on-line monitoring of CH 4 and NMHC reflects quasi-realtime release behavior of volatile compounds. • Profiles of VOCs and their released rates described by NMHC were closely related to microalgae's state of health or the life stages. • NMHC and methane were estimated from 0.02 to 0.59 μgC/(h g) and 0.05–3.96 μgC/(h g), respectively. The spectrum of Volatile Organic Compounds (VOCs) released by the microalgae-water phase of Taihu Lake in China was examined, then release behaviors were studied using non-methane hydrocarbons (NMHC, including a few polar organics) to describe the total amount of the released VOCs. Coupled dynamic headspace sampling with on-line monitoring of methane and NMHC was used to reflect the quasi-realtime release behavior of methane and NMHC by the microalgae-water phase. Alkanes, alkenes, oxygenated VOCs (OVOCs) and volatile sulfide chemicals (VOSCs) were detected. Their relative contents over time varied markedly from the stationary to the apoptosis phase, with their release rates as described by NMHC estimated from 0.02 to 0.59 μgC/(h g). Methane was investigated simultaneously, and its release rate was found to be 0.05–3.96 μgC/(h g). The release rates of both NMHC and methane were found to relate to the culture phase of the microalgae. [ABSTRACT FROM AUTHOR]

Floral scents vary spatially within flowers and inflorescences, with effects on pollinator behaviour. Here, we restudied the spatial scent pattern of Arum maculatum , an Araceae, with a higher spatial resolution than previously. The inflorescence of this species consists of a spadix, whose distal part is a sterile osmophore called the appendix, whereas its basal part bears sterile and fertile male and female flowers. This spadix is surrounded by a spathe, which forms a floral chamber around the flowers. So far, it was known that the appendix is responsible for the emission of most of the volatiles, but some volatiles were specifically found within the floral chamber, with the organ(s) responsible for their emission being unclear. By repeatedly collecting (dynamic headspace) and analysing (gas chromatography/mass spectrometry) the scent of whole inflorescences and of inflorescences with the spathe and the various zones of the spadix sequentially removed, we determined and quantified all scent compounds of the major units of the inflorescence of A. maculatum. We confirm that the inflorescence scent is mainly composed of scents released by the appendix, and we for the first time provide evidence that the male flower zone of the spadix also contributes to the inflorescence scent. Future studies are needed to test whether, and if, how, this spatial scent pattern in A. maculatum affects the movement of pollinators within the inflorescence and their pollination effectiveness. • The inflorescence of deceptive Arum maculatum consists of a spadix and a spathe. • The appendix, a sterile part of the spadix, releases most inflorescence scents. • Bicyclogermacrene is specifically released from male flower zones. • No evidence that female flower zone-specific compounds are released. [ABSTRACT FROM AUTHOR]

Floral scent is an important trait in plant–pollinator interactions. It not only varies among plant species but also among populations within species. Such variability might be caused by various non–selective factors, or, as has been shown in some instances, might be the result of divergent selective pressures exerted by variable pollinator climates. Cypripedium calceolus is a Eurasian deceptive orchid pollinated mainly by bees, which spans wide altitudinal and latitudinal gradients in mainly quite isolated populations. In the present study, we investigated whether pollinators and floral scents vary among different latitudes. Floral scents of three C. calceolus populations in the Southern Alps were collected by dynamic headspace and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). These data were completed by previously published scent data of the Northern Alps and Scandinavia. The scent characteristics were compared with information on pollinators recorded for present study or available in the literature. More than 80 scent compounds were overall recorded from plants of the three regions, mainly aliphatics, terpenoids, and aromatics. Seven compounds were found in all samples, and most samples were dominated by linalool and octyl acetate. Although scents differed among regions and populations, the main compounds were similar among regions. Andrena and Lasioglossum species were the main pollinators in all three regions, with Andrena being relatively more abundant than Lasioglossum in Scandinavia. We discuss natural selection mediated by pollinators and negative frequency–dependent selection as possible reasons for the identified variation of floral scent within and among populations and regions.

Abstract Iris species can adopt different pollination strategies to attract their pollinators, generalized shelter-mimicking, specialized deceptive sexual-mimicking or food-rewarding. As attractive stimuli, Iris flowers may use their colours, large-size, symmetry, and volatile organic compounds (VOCs). However, relatively few studies investigated Iris floral olfactory cues in the context of plant-visitor/pollinator interactions. In the present study we combined the identification of the floral volatiles of the nectariferous I. planifolia with insects visiting its flowers to gather data on its biology. Floral volatiles were collected in the natural environment by dynamic headspace and analysed by gas chromatography-mass spectrometry (GC-MS). Insect visitors/pollinators were also recorded. The volatile bouquet was aromatic-dominated with 1,4 dimethoxybenzene as major compound. Among the insects visiting its flowers, bumble and honey bees were the most abundant followed by hover flies. Overall, our results suggest that I. planifolia advertises its food reward by an aromatic dominated volatile composition. Graphical abstract Iris planifolia (Iridaceae) advertises its food reward by an aromatic dominated floral volatile composition. Image Highlights • Aromatic compounds dominate the floral scent bouquet. • 1,4-dimethoxybenzene is the major compound. • The floral scent advertises a food-rewarding species. • Bumble and honey bees are pollinators whereas a syrphid fly is visitor. • Floral olfactory cues probably act in synergy with visual ones to attract bees and flies. [ABSTRACT FROM AUTHOR]

Highlights • Dynamic headspace-GC–MS is an efficient methodology for olive oil classification. • PARADISe software for advanced deconvolution in non-targeted approaches. • Important complement to the official “PANEL TEST” method for quality control. Abstract The capabilities of dynamic headspace entrainment followed by thermal desorption in combination with gas chromatography (GC) coupled to single quadrupole mass spectrometry (MS) have been tested for the determination of volatile components of olive oil. This technique has shown a great potential for olive oil quality classification by using an untargeted approach. The data processing strategy consisted of three different steps: component detection from GC–MS data using novel data treatment software PARADISe, a multivariate analysis using EZ-Info, and the creation of the statistical models. The great number of compounds determined enabled not only the development of a quality classification method as a complementary tool to the official established method “PANEL TEST” but also a correlation between these compounds and different types of defect. Classification method was finally validated using blind samples. An accuracy of 85% in oil classification was obtained, with 100% of extra virgin samples correctly classified. [ABSTRACT FROM AUTHOR]

The study explores the complex volatile fraction of extra-virgin olive oil by combining high concentration-capacity headspace approaches with comprehensive two-dimensional gas chromatography, which is coupled with time of flight mass spectrometry. The static headspace techniques in this study are: (a) Solid-phase microextraction, with multi-polymer coating (SPME- Divinylbenzene/Carboxen/Polydimethylsiloxane), which is taken as the reference technique; (b) headspace sorptive extraction (HSSE) with either a single-material coating (polydimethylsiloxane—PDMS) or a dual-phase coating that combines PDMS/Carbopack and PDMS/EG (ethyleneglycol); (c) monolithic material sorptive extraction (MMSE), using octa-decyl silica combined with graphite carbon (ODS/CB); and dynamic headspace (d) with either PDMS foam, operating in partition mode, or Tenax TA™, operating in adsorption mode. The coverage of both targeted and untargeted 2D-peak-region features, which corresponds to detectable analytes, was examined, while concentration factors (CF) for a selection of informative analytes, including key-odorants and off-odors, and homolog-series relative ratios were calculated and the information capacity was discussed. The results highlighted the differences in concentration capacities, which were mainly caused by polymer-accumulation characteristics (sorptive/adsorptive materials) and its amount. The relative concentration capacity for homologues and potent odorants was also discussed, while headspace linearity and the relative distribution of analytes, as a function of different sampling amounts, was examined. This last point is of particular interest in quantitative studies where accurate data is needed to derive consistent conclusions.

The impact of surfactant structure and composition on the micellar partitioning of hydrophobic fragrance molecules was studied. Based on molecular diffusion coefficients derived from self-diffusion NMR spectroscopy the partition coefficient K M between water and micellar phases turned out to be directly proportional to the octanol-water partition coefficient P O/W of the fragrance molecules. By partially replacing the main surfactant sodium laureth sulfate with low- and high-molecular weight co-surfactants a shift of the fraction of fragrance molecules towards the water phase could be observed. The shift is related to a change in the hydrophobic environment inside the micelles as evidenced by fluorescence spectroscopy. A micellar affinity factor was defined and free energy differences were calculated that take into account the compatibility between solute and micellar core. A variation of micellar affinity of up to a factor of 10 was observed between various surfactant systems and mixtures, affecting significantly the proportions of the fragrance molecules in micellar and water phases. According to the Henry’s law constant, the availability of volatile fragrance molecules in the aqueous phase has a direct impact on the headspace concentration in a liquid-gas equilibrium. The shift of fragrance molecules towards the water phase and a subsequent concentration increase in the gas phase was experimentally confirmed by dynamic headspace measurements. The selection of type and composition of surfactant has thus a direct consequence on the concentration of volatiles in the gas phase and on the final perceived fragrance intensity. [ABSTRACT FROM AUTHOR]

In this study, optimum process parameters for supercritical carbon dioxide (CO2) (SC-CO2) extraction of roasted pistachio (Pistacia vera L.) were investigated by depending on amount of the characteristic flavouring components (α-pinene, limonene-D, α-terpinolene and β-myrcene). The extracts were analysed by DHA/GC-MS for determination of the volatile compounds and the optimum process parameters were decided as 200 g, 350 Bar, 70°C, 75 g CO2/min and 60 min. In the pistachio extracts obtained having the optimum process parameters, α-pinene, β-myrcene, limonene-D and α-terpinolene were detected as 24.47 g/100 g, 0.52 g/100 g, 2.25 g/100 g and 5.70 g/100 g among 31 volatile compounds in total, respectively. The fatty acid composition of the extract, which had the most desirable taste and flavour, was detected by gas chromatography using fatty acid methyl esters (FAME) preparation. The fatty acid composition analysis showed that the pistachio extract had included mostly oleic acid (67.51%, w/w) and linoleic acid (17.85%, w/w). [ABSTRACT FROM AUTHOR]

It has been known since Stefan Vogel’s observations in 1969 that solitary female oil bees collect fatty floral oils from specialized oil-secreting plants with the aid of hairy patches on either their legs or abdomen, a reward used as food for their larvae and/or to line their brood cells. Similar adaptations are also known from male oil bees, although the purpose of their oil-collecting behavior has not yet been clarified. Here, we describe a novel pollination system involving male Paratetrapedia oil bees and the tropical herb Anthurium acutifolium . We present ultrastructural morphological details of bee and plant structures involved in this interaction and the composition of floral scents likely mediating pollinator attraction. Inflorescences of A. acutifolium were visited almost exclusively by male P. chocoensis oil bees. The bees mopped with a hairy patch of their abdominal sterna 3 across the inflorescence surface. During this activity on both staminate and pistillate stage inflorescences, bees’ abdomens and legs became loaded with pollen and contacted receptive stigmas. In contrast to what has been observed in other angiosperms visited for the collection of fatty floral oils, the inflorescences/flowers of A. acutifolium do not have structures specialized in oil secretion, i.e., elaiophores. These inflorescences, nonetheless, were strongly scented during the time interval they were visited by the bees. Gas chromatography/mass spectrometry (GC/MS) analyses of dynamic headspace floral samples revealed that inflorescences of both anthetic phases emitted scent bouquets consisting mainly of aliphatic esters, indole and uncommmon terpenoids (megastigmanes). Interestingly enough, our data suggest that the unusual floral scent of A. acutifolium is a perfume reward collected by male P. chocoensis oil bees. This pollination system thus bears a remarkable resemblence with the interactions between perfume-collecting male euglossine bees and their preferred flowers, discovered by Stefan Vogel half a century ago. [ABSTRACT FROM AUTHOR]

Floral scent is a key mediator in many plant-pollinator interactions. It is known to vary not only among plant species, but also within species among populations. However, there is a big gap in our knowledge of whether such variability is the result of divergent selective pressures exerted by a variable pollinator climate or alternative scenarios (e.g., genetic drift). Cypripedium calceolus is a Eurasian deceptive lady's-slipper orchid pollinated by bees. It is found from near sea level to altitudes of 2500 m. We asked whether pollinator climate and floral scents vary in a concerted manner among different altitudes. Floral scents of four populations in the Limestone Alps were collected by dynamic headspace and analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Flower visitors and pollinators (the subset of visitors with pollen loads) were collected and identified. Preliminary coupled gas chromatographic and electroantennographic measurements with floral scents and pollinators revealed biologically active components. More than 70 compounds were detected in the scent samples, mainly aliphatics, terpenoids, and aromatics. Although several compounds were found in all samples, and all samples were dominated by linalool and octyl acetate, scents differed among populations. Similarly, there were strong differences in flower visitor spectra among populations with most abundant flower visitors being bees and syrphid flies at low and high altitudes, respectively. Pollinator climate differed also among populations; however, independent of altitude, most pollinators were bees of Lasioglossum, Andrena, and Nomada. Only few syrphids acted as pollinators and this is the first record of flies as pollinators in C. calceolus. The electrophysiological tests showed that bees and syrphid flies sensed many of the compounds released by the flowers, among them linalool and octyl acetate. Overall, we found that both floral scent and visitor/pollinator climate differ among populations. We discuss whether interpopulation variation in scent is a result of pollinator-mediated selection. [ABSTRACT FROM AUTHOR]

Recent technological advances in dynamic headspace sampling (D-HS) and the possibility to automate this sampling method have lead to a marked improvement in its the performance, a strong renewal of interest in it, and have extended its fields of application. The introduction of in-parallel and in-series automatic multi-sampling and of new trapping materials, plus the possibility to design an effective sampling process by correctly applying the breakthrough volume theory, have make profiling more representative, and have enhanced selectivity, and flexibility, also offering the possibility of fractionated enrichment in particular for high-volatility compounds. This study deals with fractionated D-HS ability to produce a sample representative of the volatile fraction of solid or liquid matrices. Experiments were carried out on a model equimolar (0.5 mM) EtOH/water solution, comprising 16 compounds with different polarities and volatilities, structures ranging from C5 to C15 and vapor pressures from 4.15 kPa (2,3-pentandione) to 0.004 kPa (t-β-caryophyllene), and on an Arabica roasted coffee powder. Three trapping materials were considered: Tenax TA™ (TX), Polydimethylsiloxane foam (PDMS), and a three-carbon cartridge Carbopack B/Carbopack C/Carbosieve S-III™ (CBS). The influence of several parameters on the design of successful fractionated D-HS sampling. Including the physical and chemical characteristics of analytes and matrix, trapping material, analyte breakthrough, purge gas volumes, and sampling temperature, were investigated. The results show that, by appropriately choosing sampling conditions, fractionated D-HS sampling, based on component volatility, can produce a fast and representative profile of the matrix volatile fraction, with total recoveries comparable to those obtained by full evaporation D-HS for liquid samples, and very high concentration factors for solid samples. [ABSTRACT FROM AUTHOR]

Summary: Volatile organic compounds (VOCs) play important roles in the environmental adaptation and fitness of plants. Comparison of the qualitative and quantitative differences in VOCs among closely related taxa and assessing the effects of environment on their emissions are important steps to deducing VOC function and evolutionary importance.Headspace VOCs from five taxa of sagebrush (Artemisia, subgenus Tridentatae) growing in two common gardens were collected and analyzed using GC‐MS.Of the 74 total VOCs emitted, only 15 were needed to segregate sagebrush taxa using Random Forest analysis with a low error of 4%. All but one of these 15 VOCs showed qualitative differences among taxa. Ordination of results showed strong clustering that reflects taxonomic classification. Random Forest identified five VOCs that classify based on environment (2% error), which do not overlap with the 15 VOCs that segregated taxa.We show that VOCs can discriminate closely related species and subspecies of Artemisia, which are difficult to define using molecular markers or morphology. Thus, it appears that changes in VOCs either lead the way or follow closely behind speciation in this group. Future research should explore the functions of VOCs, which could provide further insights into the evolution of sagebrushes. [ABSTRACT FROM AUTHOR]

Inflorescences of Araceae pollinated by cyclocephaline scarab beetles are visited frequently by a wide array of other arthropods that exploit floral resources without taking part in pollination, including earwigs, flies, and true bugs. To date, nothing is known about the cues these insect visitors use to locate the inflorescences and whether or to what extent floral scents play a role. An aroid visited by large numbers of plant bugs (Miridae) in addition to cyclocephaline scarab beetle pollinators is the Neotropical species Dieffenbachia aurantiaca. We identified the plant bug species and investigated their behavior and arrival time on the inflorescences. To test the importance of olfactory cues in locating their host we conducted experiments with open and gauze-bagged inflorescences as well as natural scent samples of D. aurantiaca. Inflorescence scents were analyzed by gas chromatography linked to mass spectrometry (GC/MS), and the attractive potential of the main scent compound was determined by behavioral assays. Three species of Neella, the most common one being N. floridula, visited the inflorescences at nightfall, shortly after the beginning of scent emission, and showed feeding and copulation activity. Bagged inflorescences as well as natural scent samples attracted similar numbers of plant bugs as the non-bagged inflorescences, showing that olfactory cues are sufficient for them to locate their host. Cis-jasmone was the major component within the inflorescence scent bouquet. In two-choice field bioassays, this compound proved to be highly attractive to Neella, and thus obviously plays a key role in finding host plants. [ABSTRACT FROM AUTHOR]

The article focuses on conducting an experiment to modify the Metropolitan Museum of Art's Oddy test and highlights the evaluation of volatiles that were identified using gas chromatography-mass spectrometry. Topics discussed include corrosion of copper, silver and lead coupons associated with the chemicals identified using chromatographic methods, intensity of acetic acid volume showing a temporary rating in the Oddy test, and evaluation of silicone stopper and three dimensional printed nylon sample holder and a custom-made lid.

The analysis of water samples containing volatile organic compounds has become an important task in analytical chemistry. Gas chromatography has been widely used for the analysis of volatile organic compounds in water. The headspace analysis shows as a principal characteristic the possibility of determination of the volatile components in drinking water. Benzene, Toluene and Xylene (BTX) are important compounds usually present in drinking water, from contamination by petroleum derivatives. Since they are toxic compounds even when present in low concentration levels, their determination is important in order to define the quality of the water. The sampling technique using headspace, coupled with gas chromatography as the separation method, showed to be suitable for BTX analysis in several samples at the mug/L (ppb) level.

In plants, the oxidative cleavage of carotenoid substrates produces volatile apocarotenoids, including α-ionone, β-ionone, and dihydro-β-ionone, compounds that are important in herbivore-plant communication. For example, β-ionone is part of an induced defense in canola, Brassica napus, and is released following wounding by herbivores. The objectives of the research were to evaluate whether these volatile compounds would: 1) be released in higher quantities from plants through the over-expression of the carotenoid cleavage dioxygenase1 ( CCD1) gene and 2) cause herbivores to be repelled or attracted to over-expressing plants relative to the wild-type. In vivo dynamic headspace collection of volatiles coupled with gas chromatography-mass spectrometry was used to determine volatile organic compounds (VOC) in the headspace of the Arabidopsis thaliana ecotype Columbia-0 (L.) over-expressing the AtCCD1 gene. The analytical method allowed the detection of β-ionone in the Arabidopsis headspace where emission rates ranged between 2 and 5-fold higher compared to the wild type, thus corroborating the in vivo enhancement of gene expression. A two chamber choice test between wild type and AtCCD1 plants revealed that crucifer flea beetle Phyllotreta cruciferae (Goeze) adults were repelled by the AtCCD1 plants with the highest transcription and β-ionone levels. α-Ionone and dihydro-β-ionone were not found in the headspace analysis, but solutions of the three compounds were tested in the concentration range of β-ionone found in the Arabidopsis headspace (0.05 to 0.5 ng/μl) in order to assess their biological activity with crucifer flea beetle, two spotted spider mite Tetranychus urticae (Koch), and silverleaf whiteflies Bemisia tabaci (Gennadius). Choice bioassays demonstrated that β-ionone has a strong repellent effect toward both the flea beetle and the spider mite, and significant oviposition deterrence to whiteflies. In contrast, dihydro-β-ionone had attractant properties, especially to the crucifer flea beetle, while α-ionone did not show any significant activity. These findings demonstrate how regulating genes of the carotenoid pathway can increase herbivore deterrent volatiles, a novel tool for insect pest management. [ABSTRACT FROM AUTHOR]

Sampling teams performing work at sea in areas where chemical munitions may have been dumped require rapid and reliable analytical methods for verifying sulfur mustard leakage from suspected objects. Here we present such an on-site analysis method based on dynamic headspace GC–MS for analysis of five cyclic sulfur mustard degradation products that have previously been detected in sediments from chemical weapon dumping sites: 1,4-oxathiane, 1,3-dithiolane, 1,4-dithiane, 1,4,5-oxadithiephane, and 1,2,5-trithiephane. An experimental design involving authentic Baltic Sea sediments spiked with the target analytes was used to develop an optimized protocol for sample preparation, headspace extraction and analysis that afforded recoveries of up to 60–90%. The optimized method needs no organic solvents, uses only two grams of sediment on a dry weight basis and involves a unique sample presentation whereby sediment is spread uniformly as a thin layer inside the walls of a glass headspace vial. The method showed good linearity for analyte concentrations of 5–200 ng/g dw, good repeatability, and acceptable carry-over. The method's limits of detection for spiked sediment samples ranged from 2.5 to 11 μg/kg dw, with matrix interference being the main limiting factor. The instrumental detection limits were one to two orders of magnitude lower. Full-scan GC–MS analysis enabled the use of automated mass spectral deconvolution for rapid identification of target analytes. Using this approach, analytes could be identified in spiked sediment samples at concentrations down to 13–65 μg/kg dw. On-site validation experiments conducted aboard the research vessel R/V Oceania demonstrated the method's practical applicability, enabling the successful identification of four cyclic sulfur mustard degradation products at concentrations of 15–308 μg/kg in sediments immediately after being collected near a wreck at the Bornholm Deep dumpsite in the Baltic Sea. [ABSTRACT FROM AUTHOR]

Instant coffee is awidespread product, generally related to a high consumer acceptability, also because of its ease of preparation. The present work addresses the characterization of the headspace of freshly brewed instant coffees resulting from different blends, during and immediately after preparation. The sample set consisted of 10 coffees, obtained by mixing three different blends in different proportions. The employment of Proton Transfer Reaction-Mass Spectrometry (PTR-MS) allowed for direct and real-time sampling from the headspace, under conditions that mimic those that are encountered above the cup during and right after brewing. Different coffee brews were separated on the basis of the respective volatile profiles, and data showed good consistency with the respective blend compositions. When the headspace evolution was monitored during preparation, similar results were obtained in terms of blend separation;moreover, different blends displayed different and reproducible 'signatures' in terms of time evolution. A straightforwardmethod for the prediction of headspace composition is proposed, allowing to predict the volatile profiles of two-component and three-component blends on the basis of the respective parent components. Overall, the results constitute a successful example of the applicability of PTR-MS as a tool for product development in food science. [ABSTRACT FROM AUTHOR]

Static and dynamic headspace techniques have been applied to the extraction and concentration of volatile organic compounds (VOCs) from paprika oleoresin. In dynamic headspace, both purge and trap and sweeping techniques have been used. In order to show the influence of temperature on the extraction techniques, three differents temperatures have been applied to each technique. The separation and identification of the extracted VOCs has been carried out through HRGC/MS. The extraction techniques are simple and easily reproducible.

Concentrating cashew apple juice alters the beverage aroma and flavor, compromising consumer acceptability of the concentrated beverage. To understand the mechanisms involved in these changes, this research characterized the dynamics of the loss and emergence of volatile compounds during cashew apple juice concentration, reporting their impact on beverage sensory quality. Fresh cashew apple juice (10.3°Brix) was concentrated in a thermal-siphon type evaporator operating in a closed system. Five samples were taken throughout the concentration process with the following soluble solids contents: 11.8°Brix, 14.9°Brix, 20.2°Brix, 29.6°Brix and 42.1°Brix. Trained judges rated the aroma note intensities, described as “fresh cashew apple” and “cooked” as perceived in the fresh and concentrated beverages. The headspace volatiles of the six samples were identified and quantified by GC–MS. The results indicated the esters as the major component in the fresh juice (226.46 μg kg − 1 ) representing 45.0% of the total mass of volatiles, followed by the terpenes (118.98 μg kg − 1 ), acids (45.23 μg kg − 1 ), aldehydes (39.10 μg kg − 1 ), alcohols (18.91 μg kg − 1 ), lactones (19.15 μg kg − 1 ), hydrocarbons (18.02 μg kg − 1 ) and ketones (11.05 μg kg − 1 ). Predictive statistical models (R 2 > 0.956, p ≤ 0.002) revealed that on reaching 14.9°Brix, the ester concentration declined more than 90%, the terpene content almost 100%, alcohols 85%, aldehydes 80% and hydrocarbons 90%. At 14.9°Brix, the intensity of “fresh cashew apple” aroma still predominated in the juice, but the panelists detected the presence of a weak “cooked” aroma. Concentration of the beverage to 20.2°Brix or above expressively increased the cooked aroma intensity and the concentration of hydrocarbons, alcohols and some aldehydes usually associated with off-flavors such as pentanal and decanal. This raises the possibility that some of these compounds might have been formed during juice processing. Juice with better sensory quality could possibly be obtained by concentrating the beverage to levels below 20.2°Brix, recovering the esters that evaporated off the juice until ~ 15°Brix is reached, and re-adding them to the juice concentrated. [ABSTRACT FROM AUTHOR]

In this work, we report the detection in air of two families of illicit drugs using a high sensitivity portable instrument based on a Field Asymmetric Ion Mobility Spectrometry microchip sensor. Methamphetamine, Amphetamine and Δ 9 -Tetrahydrocannabinol (Δ 9 -THC) were detected in the vapor phase at atmospheric pressure and a concentration of 12.5, 25 and 65 ppb, respectively. Each target molecule appears at a specific Compensation Voltage (CV) under a fixed Dispersion Field (DF). A linear FAIMS response at different concentrations and low limits of detection were successfully achieved. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new GC/TOFMS method for the quantitation of boar taint compounds in pig fat is presented. [•] An optimised dynamic headspace-thermal desorption sampling achieves a solvent-free quantitation. [•] Isotopically labeled internal standards are used to compensate matrix effects. [•] Validation data demonstrate high sensitivity, accuracy and precision. [•] Matrix effects on the partitioning of boar taint compounds between fat and gas phase can be evaluated. [ABSTRACT FROM AUTHOR]

Sulfur-fumigation is known to reduce volatile compounds that are the main active components in herbs used in herbal medicine. We investigated changes in chemical composition between sun-dried and sulfur-fumigated Radix Angelicae Dahuricae using a purge and trap technique to capture volatile compounds, and two-dimensional gas chromatography/time-of-flight mass spectrometry for identification. Using sun-dried Radix Angelicae Dahuricae samples as a reference, the results showed that 73 volatile compounds, including 12 sulfide compounds, were found to be present only in sulfur-fumigated samples. Furthermore, 32 volatile compounds that were found in sun-dried Radix Angelicae Dahuricae samples disappeared after sulfur-fumigation. The proposed method can be applied to accurately discriminate sulfur-fumigated Radix Angelicae Dahuricae from different commercial sources. [ABSTRACT FROM AUTHOR]

A dynamic headspace sorptive extraction (DHS) combined with thermal desorption (TD) and coupled with gas chromatography–mass spectrometry (GC/MS) was developed for the determination of 11 esters which contribute to the fruity aroma in sweet wines. A full factorial (4 factors, 2 level) experiment design was used to optimize the extraction conditions and the results were evaluated by multiple linear regression (MLR) and principal component analysis (PCA). The esters showed optimal extraction using an extraction temperature of 30°C during 20min, and a subsequent purge volume of 300mL and dry volume of 50mL. Afterwards, quantification was achieved using calibration curves constructed for each ester with linear regression equations having correlation coefficients (R 2) ranging from 0.9894 to 0.9981. The proposed method was successfully validated and showed good intermediate precision, repeatability and accuracy values for all the monitored compounds. Finally, the method was applied to quantify esters, with fruity aromatic notes, of sweet white and red wines, elaborated with different winemaking processes. [ABSTRACT FROM AUTHOR]

Highlights: [•] An Online PTV inlet allows for direct sampling and quantitation of TATP vapor via GC/MS. [•] Estimates of vapor concentration determined from mass loss of a solid sample are in good agreement with GC/MS quantitation. [•] Vapor concentration varies from 50 to 5400ngL−1. [ABSTRACT FROM AUTHOR]

The gas-liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RF/RF) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling. [ABSTRACT FROM AUTHOR]

Biogas slurry is not suitable for liquid fertilizer due to its high amounts of volatile materials being of complicated composition and peculiar smell. In order to remove volatiles from biogas slurry efficiently, the dynamic headspace and gas chromatography-mass spectrometry were used to clear the composition of volatiles. Nitrogen stripping and superfluous ozone were also used to remove volatiles from biogas slurry. The results showed that there were 21 kinds of volatile compounds in the biogas slurry, including sulfur compounds, organic amines, benzene, halogen generation of hydrocarbons and alkanes, some of which had strong peculiar smell. The volatile compounds in biogas slurry can be removed with the rate of 53.0% by nitrogen stripping and with rate of 81.7% by the oxidization and stripping of the superfluous ozone. On this basis, the removal rate of the volatile compounds reached 99.2% by chloroform and n -hexane extraction, and almost all of odor was eliminated. The contents of some dissolved organic compounds decreased obviously and however main plant nutrients had no significant change in the biogas slurry after being treated. [ABSTRACT FROM AUTHOR]

Comprehensive 2 D GC coupled to time-of-flight mass spectrometry was applied for the characterization of the particulate phase of mainstream tobacco smoke particulate. Five 3R4F research cigarettes were smoked on a rotary smoking machine under standardized conditions, total particular matter was collected on Cambridge filter pads and extracted using methanol-based liquid extraction and dynamic headspace ( DHS) approaches. Automated peak finding and mass spectral deconvolution combined with scripting and manual revision of library hits were used to evaluate the library search results. The revised peak table contained nearly 1800 individual compounds for the DHS sample and over 900 for the solvent extracted sample. These methods of extraction were shown to be complementary, leading to only 11% of repeated analytes, and their combination gave rise to a list of almost 2500 individual compounds. [ABSTRACT FROM AUTHOR]