Phase Microextraction-gas Chromatography-mass Spectrometry Research Articles

Comparison of the volatile compounds of Dermestes maculatus and Dermestes ater pupae: application of headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS)

The headspace solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) method was used for the determination of the volatile compounds of Dermestes maculatus and D. ater pupae. These beetles are of economic importance and they are a common pest of stored products and also serve as an intermediate host of the parasitic tapeworm, therefore an understanding of their biology is very important. Analyses of the volatile compounds of D. maculatus and D. ater pupae revealed differences between the insect species in their chemical composition. Sixteen volatile compounds of D. ater pupae, including 6 hydrocarbons, 5 fatty acids, 3 esters, and 2 aldehydes were identified. The major volatile compound in D. ater pupae was pentacosane. Ten compounds were present in < 10 % concentrations. A further five were present in < 1 % concentrations. A total of 39 compounds were identified in the D. maculatus pupae, including 28 esters of fatty acid, 4 fatty acids, 6 hydrocarbons and 1 aldehyde. Two volatile compounds were detected as major compounds: octadecadienoic acid methyl ester and octadecenoic acid methyl ester. A further eight were identified in smaller quantities (from 1.12 to 8.30 %) and the remaining volatile compounds were present in < 1 % concentrations.

Solid Phase Micro-extraction – Gas Chromatography–Mass Spectrometry to Characterize Pyrolysis Products from Textiles

ABSTRACTHeadspace solid phase micro-extraction gas chromatography–mass spectrometry (HS-SPME GC–MS) was used for identifying thermally labile volatile compounds from cotton, wool, polyester, olefin, silk, and acrylic. Volatile compounds were generated from the textiles using a pyrolysis apparatus prior to GC–MS. Pyrolysis temperatures ranged from 190 to 550°C. Each textile displayed a unique chromatogram containing compounds that were consistent with the chemical structure of the textile. Experimental parameters that were investigated included the temperature, sample size, and sampling time to determine their effect on the number and intensity of peaks in the chromatograms as well as to identify optimum conditions for analysis. Heating of each sample was achieved using a resistively heated Pt wire. Full pyrolysis at 550°C of the textiles appeared to give the best results in terms of peak height relative to background. A range of sample sizes (0.02–1.5 mg) were used and, generally, ≤0.02 mg was used for identifying the textiles. The reproducibility of retention times for selected compounds in the chromatograms was less than 1% relative standard deviation. The combination with mass spectrometry provided valuable structural information.

The Equine Volatilome: Volatile Organic Compounds as Discriminatory Markers

Animals rely on subtle signals perceived between individuals that convey information such as sex, reproductive status, individual identity, ownership, competitive ability, and health status. These cues have important influences on behaviors that are vital for reproductive success, such as parent–offspring attachment, recognition of relatedness, mate choice, and territorial marking. This study investigates individual odor profiles as discriminatory markers possibly affecting equine behavior. This study investigated the volatile compounds in horses using solid phase microextraction gas chromatography-mass spectrometry and hair samples. Two horse breeds, Appaloosa (n = 6) and Quarter Horses (n = 17), were used as a model to assess the volatilome that may be used to identify individuals and kin recognition. A total of 187 volatiles were identified and demonstrated that the volatilome carries information on genetic relatedness. Interestingly, apart from individualization and kinship, the volatiles detected were also able to discriminate between breeds. The study is limited exclusively to two horse breeds and should be expanded to include other domestic and wild horses. In addition, compounds were identified based on NIST 98 mass spectral library. The results of this study support the individual odor hypothesis suggesting that each individual possesses a unique scent that acts as a characteristic or odor fingerprint. Such qualitative and quantitative patterns have not been explored in domestic or wild animals and there is a need to understand more about the influence of odor on behavior and interactions.

Factors Affecting Species Identifications of Blow Fly Pupae Based upon Chemical Profiles and Multivariate Statistics.

Alternative methods for the identification of species of blow fly pupae have been developed over the years that consist of the analyses of chemical profiles. However, the effect of biotic and abiotic factors that could influence the predictive manner for the tests have not been evaluated. The lipids of blowfly pupae (Cochliomyia macellaria, Lucilia cuprina, Lucilia sericata, and Phormia regina) were extracted in pentane, derivatized, and analyzed by total-vaporization solid phase microextraction gas chromatography-mass spectrometry (TV-SPME GC-MS). Peak areas for 26 compounds were analyzed. Here we evaluated one biotic factor (colonization) on four species of blow flies to determine how well a model produced from lipid profiles of colonized flies predicted the species of flies of offspring of wild-caught flies and found very good species identification following 10 generations of inbreeding. When we evaluated four abiotic factors in our fly rearing protocols (temperature, humidity, pupation substrate, and diet), we found that the ability to assign the chemical profile to the correct species was greatly reduced.

Evaluation of volatile profiles obtained for minimally-processed pineapple fruit samples during storage by headspace-solid phase microextraction gas chromatography-mass spectrometry

This paper describes the application of the solid-phase microextraction (SPME) technique for the determination and monitoring of the volatile profile of minimally-processed pineapple fruit stored at various temperatures (-12 °C, 4 °C and 25 °C) for different periods (1, 4 and 10 days). The SPME fiber coating composed of Car/PDMS presented the best performance. The optimal extraction conditions obtained through a Doehlert design were 60 min at 35 °C. The profiles for the volatile compounds content of the fruit at each stage of storage were determined by gas chromatography-mass spectrometry (GC-MS). The variation in the volatile profile over time was greater when the fruit samples were stored at 25 °C and at -12 °C compared to 4 °C. Thus, according to the volatile profiles associated with the storage conditions evaluated in this study, packaged pineapple retains best its fresh fruit aroma when stored at 4 °C.

The detection of active moulds on historical silk by the means of the headspace–solid phase micro-extraction–gas chromatography–mass spectrometry method

The goal of this work was to analyze the profile of microbial volatile organic compounds (MVOCs) emitted by moulds growing on silk samples in search of particular volatiles mentioned in the literature as indicators of active mould growth. The selected moulds were inoculated on three types of media: (1) samples of pure silk placed on microbial media, (2) samples of historical silk placed on microbial media, and (3) agar containing amino acids that are elements of the structure of fibroin. All samples were prepared inside vials (closed system). In the first and second cases the media did not contain any sources of organic carbon, nitrogen, or sulfur—the silk was the only nutrient for the moulds. A fourth type of sample was historical silk prepared in a Petri dish without a microbial medium and inoculated with a fibroinolytically active mould (open system). The MVOCs emitted by moulds were sampled with the headspace–solid phase micro-extraction method. Volatiles extracted on Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) fibers were analyzed in a gas chromatography–mass spectrometry system. Qualitative and quantitative analyses of chromatograms were carried out in search of indicators of metabolic activity. The results showed that there are three groups of volatiles that can be used for the detection of active forms of moulds on silk. Thus, this can be a valuable tool for the fast detection of mould activity on historical silk objects. To the best of our knowledge, this is the first work to measure MVOCs emitted by moulds growing on silk.

The Impact of Wine Style and Sugar Addition in liqueur d’expedition (dosage) Solutions on Traditional Method Sparkling Wine Composition

The purpose of this study was to investigate the effect of wine style and cane sugar addition in the liqueur d’expedition (dosage) solution on volatile aroma compounds (VOCs) in traditional method sparkling wine. There were 24 bottles of each treatment produced. Treatments were sparkling wine zero dosage (ZD); NV sparkling wine + sugar (BS); unoaked still Chardonnay wine + sugar (UC); Pinot noir 2009 sparkling wine + sugar (PN); Niagara produced Brandy + sugar (B) and Icewine (IW). The control treatment in the sensory analysis was an oaked still Chardonnay wine + sugar (OC) because the zero-dosage wine was not suitable for a difference test that compared wines with sugar to one without. Standard wine chemical parameters were analysed before disgorging and after liqueur d’expedition was added and included; pH, titratable acidity (TA g/L), alcohol (v/v %), residual sugar (RS g/L), free and total SO2 and total phenolics (A.U.). Volatile aroma compounds (VOCs) analysed by Headspace Solid- Phase Micro-Extraction Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS) included two alcohols, and six ethyl esters. ZD wines had the highest foam height and highest dissolved oxygen level. Sugar affected VOC concentrations in all treatments at five weeks post-disgorging, but by 15 weeks after liqueur d’expedition addition, the wine with added sugar had similar VOC concentrations to the ZD wines. The type of wines used in the dosage solutions had more influence on VOC concentrations than sugar addition.

Use of novel attraction compounds increases monitoring success of a rare beetle, Elater ferrugineus

Abstract The use of pheromones to determine distributions of rare saproxylic insects is an increasingly popular technique. Pheromones may, however, also be used to elucidate the biology of these cryptic species, a vital requirement if they are to be accurately monitored and conserved. We used non‐invasive aerial trapping to compare the effectiveness of chemicals produced by Elater ferrugineus L (Coleoptera: Elateridae), namely 7‐methyloctyl (Z)‐4‐decenoate (the female‐produced sex pheromone), and male compounds (geranyl and neryl acetone and 6‐methyl‐5‐heptene‐2‐one). The male compounds were identified using headspace analysis by solid phase micro‐extraction gas chromatography‐mass spectrometry. We discovered that males only produce these two compounds after having been attracted to a female, and that this serves to attract further males to a female. Such compounds do not appear to attract females but for a species that has a short activity period and is non‐feeding in the adult stage, may ensure breeding success when populations are low. By marking all beetles caught, we were able to demonstrate that recapture rate using this method is low (approximately 11% of total captures annually). Therefore, the method does not limit dispersal or breeding opportunities, making it a valuable tool for monitoring endangered saproxylic beetle species.

Performance, litter quality and gaseous odour emissions of broilers fed phytase supplemented diets.

The effect of graded levels of phytase on performance, bone characteristics, excreta/litter quality and odorant emissions was examined using 720 Ross 308 male d-old broilers. A 2 × 4 factorial arrangement of treatments was employed with 6 replicates of 15 birds per pen. Factors were: diets-positive and negative control (PC, NC); phytase – 0, 500, 1,000, 1,500 FTU/kg. The PC was formulated to meet the 2014 Ross 308 nutrient specifications, whereas the NC was formulated with lower Ca (−1.4 g/kg), available P (−1.5 g/kg), Na (−0.3 g/kg), dLys (−0.2 g/kg) and MEn (−0.28 MJ/kg) equivalent to nutrient matrix values for 500 FTU/kg phytase in the starter, grower and finisher periods (i.e., downspec diet). On d 24, phytase decreased FCR by 1.6, 4.3 and 4.6 points at inclusion levels of 500, 1,000 and 1,500 FTU/kg, respectively (P < 0.01) across all diets. Phytase by diet interactions on BW gain were observed on d 24 and 35 (P < 0.01). The effect of phytase was much more pronounced in the NC diet as compared with the PC diet. On d 24, phytase increased BW gain by 37, 55 and 68 g in the PC and 127, 233 and 173 g in the NC at 500, 1,000 and 1,500 FTU/kg, respectively. Diet by phytase interactions were also observed for tibia ash, litter quality and water to feed intake ratio (P < 0.01) with higher phytase effect in NC as compared with PC. Neither diet nor phytase impacted excreta moisture content on d 18 or 21 (P > 0.05). Solid phase micro-extraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis of gaseous emissions on d 39 indicated no difference in the emission of alcohols, aldehydes, ketones, volatile fatty acids and phenols between treatments (P > 0.05). The results indicate that phytase has greater benefits when formulated using nutrient matrix values as compared with adding it over the top in an already nutrient sufficient diet. The later method would be expected to increase feed costs without concomitant performance benefits.

Comparison of volatile organic compounds from lung cancer patients and healthy controls—challenges and limitations of an observational study

This paper outlines the design and performance of an observational study on the profiles of volatile organic compounds (VOCs) in the breath of 37 lung cancer patients and 23 healthy controls of similar age. The need to quantify each VOC considered as a potential disease marker on the basis of individual calibration is elaborated, and the quality control measures required to maintain reproducibility in breath sampling and subsequent instrumental trace VOC analysis using solid phase microextraction–gas chromatography–mass spectrometry over a study period of 14 months are described. Twenty-four VOCs were quantified on the basis of their previously suggested potential as cancer markers. The concentration of aromatic compounds in the breath was increased, as expected, in smokers, while lung cancer patients displayed significantly increased levels of oxygenated VOCs such as aldehydes, 2-butanone and 1-butanol. Although sets of selected oxygenated VOCs displayed sensitivities and specificities between 80% and 90% using linear discriminant analysis (LDA) with leave-one-out cross validation, the effective selectivity of the breath VOC approach with regard to cancer detection is clearly limited. Results are discussed against the background of the literature on volatile cancer marker investigations and the prospects of linking increased VOC levels in patients’ breath with approaches that employ sniffer dogs. Experience from this study and the literature suggests that the currently available methodology is not able to use breath VOCs to reliably discriminate between cancer patients and healthy controls. Observational studies often tend to note significant differences in levels of certain oxygenated VOCs, but without the resolution required for practical application. Any step towards the exploitation of differences in VOC profiles for illness detection would have to solve current restrictions set by the low and variable VOC concentrations. Further challenges are the technical complexity of studies involving breath sampling and possibly the limited capability of current analytical procedures to detect unstable marker candidates.

Characterisation of volatile profiles in 50 native Peruvian chili pepper using solid phase microextraction–gas chromatography mass spectrometry (SPME–GCMS)

The volatiles were characterised by headspace solid phase micro extraction (HS-SPME), gas chromatography mass spectrometry (GC-FID/MS). A total of 127 compounds were identified with terpenes (including mono terpenes and sesquiterpenes – a total of 45 compounds), esters (31 compounds) and hydrocarbons (20 compounds) were the predominant volatile compounds. Principal component analysis (PCA) of the volatile compounds yielded 2 significant PC's, which together accounted for 90.3% of the total variance in the data set and the scatter plot generated between PC1 and PC2 successfully segregated the 50 chili pepper samples into 7 groups. Clusters of hydrocarbons, esters, terpenes, aldehyde and ketones formed the major determinants of the difference.

Assessment of the key aroma compounds in rose-based products

In this study, headspace solid phase microextraction–gas chromatography-mass spectrometry and GC-olfactometry were used to analyze the key aroma compounds in three types of rose-based products, including low-temperature extracts (LTEs), high-temperature extracts (HTEs), and rose drinks (RDs). In combination with the Guadagni theory, it was confirmed that the key aroma components of LTE were β-phenyl ethyl alcohol, citronellol, geraniol, and eugenol. The main aroma compounds in HTE were β-phenyl ethyl alcohol, citronellol, geraniol, eugenol, linalool, and rose oxide. The four key aroma compounds in RDs were β-phenyl ethyl alcohol, eugenol, geraniol, and linalool.

Partial oxidation of n-pentane over vanadium phosphorus oxide supported on hydroxyapatites

Several off-the-shelf products (personal care, fragrances and oils, food) were analyzed by solid phase micro-extraction gas chromatography-mass spectrometry to determine the most prevalent volatile compounds responsible for the product aroma. Both one-dimensional and two-dimensional gas chromatography were used, and coupled with low and high-resolution, accurate mass time of flight mass spectrometry. The spectrum of components present in the different products was examined to see if a commonality of constituents could be identified which might lead to a typical fynbos aroma profile.

Characterization of volatiles Tribolium castaneum (H.) in flour using solid phase microextraction–gas chromatography mass spectrometry (SPME–GCMS)

The objective of this study was to identify volatile organic compounds (VOCs) from flour, Tribolium castaneum (Herbst) and flour infested by T. castaneum separately, to confirm the difference of healthy flour and flour infested by T. castaneum and to explore the new technique to diagnose stored flour's quality by its VOCs change. Headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) were used to detect the VOCs of three different samples. Totally, 71 different compounds were identified in flour, T. castaneum and T. castaneum infested flour. Therefore, 27 VOCs were identified from flour alone, 32 VOCs from T. castaneum and 39 VOCs from T. castaneum infested flour. The compound 2-ethyl-2,5-cyclohexadiene-1,4-dione is only found in T. castaneum infested flour. This suggests that 2-ethyl-2,5-cyclohexadiene-1,4-dione can be a useful VOC for detecting T. castaneum in flour.

Monoterpenes in cv. Zilavka Free-Run Musts from Prefermentatively Macerated Pomace

Five free volatile monoterpenes (linalool, α-terpineol, citronellol, nerol, and geraniol; FVmT) in free-run musts obtained from crushed grapes of white cv. Zilavka in two consecutive vintages (2011 and 2012) were quantified with headspace solid phase microextraction gas chromatography-mass spectrometry. Unexpectedly high concentrations of the analyzed FVmT were found in free-run musts of Zilavka, a variety of grapes (and wines) not previously described as having high monoterpene content. The most abundant monoterpenes were linalool, α-terpineol, and geraniol, with tens of μg/L of nerol. Citronellol was detectable, but its low concentration was quantified in free-run musts in only one experimental trial. Higher concentrations of the analyzed FVmT were found in the free-run musts obtained in 2012 after hot and dry summer months and an early grape harvest. Increasing maceration temperatures from 6 to 12°C, and then to 20°C during the 20-hr treatment resulted in increased extraction of FVmT. However, only the increases in nerol concentrations were statistically significant with increases found with higher maceration temperatures in both years. The calculated odor activity values for linalool, α-terpineol, and geraniol were relatively high (1.6 to 8). The results indicated monoterpenic potentials of Zilavka. Thus, there is an opportunity for wine producers to consider technological modifications directed to the extraction of FVmT and monoterpene profiling of Zilavka wines.

QUALITY CONTROL OF ZINGIBER OFFICINALE OILS IN PRODUCT FORMULATIONS

Zingiber officinale (ginger) is one of the most commonly used flavouring ingredients in food and culinary dishes. The essential oils are known for its unique aroma and characteristic and widely used as therapy. In this study, the essential oil was formulated as massage oil and the quality of massage oil was evaluated on its physicochemical properties, i.e. colour, odour, density, viscosity, refractive index and pH value. The efficacy of the product was determined by the value of the melanin (coloured pigment) and erythema (redness of skin) as well skin irritation analysis (Finn Chamber Patch). The massage oil was also tested using Head Space-Solid Phase Microextraction-Gas Chromatography Mass Spectrometry (HS-SPME-GCMS) to determine the presence of ginger’s essential oils important chemical constituents in the massage oil. Analysis revealed the presence of a-zingiberene, neral and geranial which are the main components found in ginger massage oil. For safety use, the finished product was tested for microbial enumeration test and heavy metal analysis. Result showed that there was no microbial contamination and meets the British Pharmacopoeia 2011 specifications in topical use. Meanwhile the results of limit test for heavy metals were found to be below detectable levels of National Pharmaceutical Control Bureau specifications.

Analysis of volatiles from stored wheat and Rhyzopertha dominica (F.) with solid phase microextraction-gas chromatography mass spectrometry.

Volatile organic compounds (VOCs) contribute significantly to food flavour and can be used as indicators of quality, age of storage, and hygiene condition of stored products. The VOCs in the headspace of three different samples - healthy wheat, Rhyzopertha dominica, and wheat with R. dominica - were analysed at 25°C by solid phase micro-extraction (SPME) coupled with gas chromatography-flame ionisation detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). All the experimental conditions were kept consistent except a polar column and a non-polar column were used to assess the differences in volatile fingerprints. A total of 114 volatiles were identified by both the polar and non-polar columns, of which 48 were specific to one of the three samples tested. The volatiles were mainly carbonyl chemical compounds such as aldehydes, ketones and alcohols. GC-MS results showed slightly more VOCs were identified from the polar column. The total number for the three samples was 43 from the polar column compared to 39 from the non-polar column. Conversely, 30 VOCs unique to a given sample were identified from the non-polar column compared to 18 from the polar column. The use of both polar and non-polar columns is essential to capture the full range of VOCs produced by the three specific sample types investigated. The data can form the basis of enquiry into the relationship between storage and grain quality, and insect infestation and grain quality by observing the impact that these circumstances have on the production of volatile organic compounds.

The sensory evaluation of 2,4,6-trichloroanisole in wines

This work proposes a sensory method to verify the ‘cork taint’ defect in food and beverages. This off-flavour has considerable economic impact in wine but occasionally can occur in other food and beverages. In wine, 2,4,6-trichloroanisole (TCA) is generally considered to be the main compound responsible for this taint. It is an easily recognized compound because of its low sensorial threshold, and it is described as a mouldy and damp cardboard odour. This sensory method, developed in wine, consists of specific panel training to recognize TCA in a series of olfactory tests. The effectiveness of the panel was tested with contaminated wines in which the TCA content had been previously determined by Solid Phase Microextraction-Gas Chromatography Mass Spectrometry (SPME-GC/MS) analysis. This sensory method is useful to train a panel able to recognize the ‘cork taint’ defect in different situations (legal appraisals or quality assurance systems). The use of a reliable sensory assay can reduce the number of chemical analyses and the proposed method can be applied to other beverages such as beer. Copyright © 2015 The Institute of Brewing & Distilling

Volatile aroma and sensory analysis of black raspberry wines fermented by different yeast strains

Robus coreanus Miquel is a small berry fruit used for Korean black raspberry (KBR) wine-making. Twelve different yeast strains were investigated by laboratory-scale fermentation to develop a wine with a high flavour quality. Volatile aroma compounds from the wines were analysed using headspace–solid phase microextraction–gas chromatography–mass spectrometry and sensory evaluation was performed to evaluate the flavour characteristics. The volatile aroma compounds that mostly contributed to the flavour of KBR wines were those related to fruity (esters) and floral (terpenes) aromas. Fifteen out of the 67 identified volatile compounds showed higher odour activity values than other compounds in the wines, and these compounds were considered as important contributors to the final aromas of the wine. Additionally, the KBR wine fermented by the M1 yeast strain had the highest sensory preference because of higher fruity and floral aroma characters compared with other wines. In addition to the M1 strain, the other yeast strains that produced favourable sensory characteristics included Enoferm CSM, Uvaferm VRB, Lalvin ICV GRE, Lalvin ICV Opale and LevureSeche Active. Of these strains, the M1 strain produced a particularly excellent black raspberry wine, and thus could be applied for further large-scale production of black raspberry wines. It is also expected that this work will expedite research on the production of high-quality black raspberry wines with beneficial physicochemical properties, functionality and good sensory characteristics. Copyright © 2015 The Institute of Brewing & Distilling

Influence of storage on volatile profiles in roasted almonds (Prunus dulcis).

Hexanal, peroxide value, and lipid hydroperoxides are common indicators of lipid oxidation in food products. However, these markers are not always reliable as levels are dynamic and often can be detected only after significant oxidation has occurred. Changes in the volatile composition of light- and dark-roast almonds were evaluated during storage over 24 weeks at 25 or 35 °C using headspace solid phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). Several volatile changes were identified in association with early oxidation events in roasted almonds. Hexenal decreased significantly during the first 6 weeks of storage and did not increase above initial levels until 20-24 weeks of storage depending upon the degree of roast. In contrast, levels of 1-heptanol and 1-octanol increased at 16-20 weeks, depending upon the degree of roast, and no initial losses were observed. Seventeen new compounds, absent in raw and freshly roasted almonds but detectable after 6 weeks of storage, were identified. Of these, 2-octanone, 2-nonanone, 3-octen-2-one, 2-decanone, (E)-2-decenal, 2,4-nonadienal, pentyl oxirane, and especially acetic acid increased significantly (that is, >10 ng/g). The degree of roasting did not correlate with the levels of these compounds. Significant decreases in roasting-related aroma volatiles such as 2-methylbutanal, 3-methylbutanal, furfural, 2-phenylacetaldehyde, 2,3-butanedione, 2-methylpyrazine, and 1-methylthio-2-propanol were observed by 4 weeks of storage independent of the degree of roast or storage conditions.