Gas Chromatographic-mass Spectral Analysis Research Articles

Chemical constituents and in vitro antimicrobial activity of rhizome essential oils of Zingiber densissimum S.Q.Tong & Y.M.Xia and Kaempferia laotica Gagnep. growing wild in Vietnam

Zingiber densissimum S.Q.Tong & Y.M.Xia and Kaempferia laotica Gagnep., belong to the Zingiberaceae family, which were found in Vietnam and Laos in recent years. To date, there has been very limited information on their phytochemical profiles and pharmacological activities. The present study was conducted to give insights into the chemical composition of the essential oils isolated from two plants and their antimicrobial activities. Gas Chromatographic–Mass Spectral (GC-MS) analysis was utilized to identify the chemical composition of the rhizome essential oils of Z. densissimum and K. laotica. The antimicrobial activities were evaluated on three Gram-positive bacterial strains, three Gram-negative bacterial strains, and a pathogenic yeast. The GC-MS analysis showed that β-pinene (38.36%), β-phellandrene (26.85%), and α-pinene (13.31%) were the most dominant components in Z. densissimum rhizome essential oil, while K. laotica rhizome essential oil was found to contain mainly camphene (23.44%), α-pinene (10.69%), 3-carene (8.60%) and β-pinene (6.85%). As for the antimicrobial activity test results, the rhizome essential oil of Z. densissimum displayed potent activities against Candida albicans (MIC value = 2 μg/mL), Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli (MIC values = 8 μg/ mL). Meanwhile, the rhizome essential oil of K. laotica showed weaker activities against all investigated microbial strains (MIC values ranging from 32 to 256 μg/mL). The study results indicated the chemical constituents of the essential oils prepared from these plants. The two essential oil samples were also shown to exhibit potential antimicrobial activities against several pathogenic bacterial and fungal strains.

Isolation, Characterization and Antimicrobial Activity of Endophytic Actinobacteria from Medicinal Plants

The current study is aimed to isolate endophytic actinobacteria from various medicinal plants for exploring its antimicrobial activity against clinical pathogens. Out of 50 actinobacterial cultures isolated from eleven medicinal plants, 58 % of the cultures showed antimicrobial activity against at least two out of nine pathogens tested. Strain KCA1 isolated from Phyllanthus niruri leaves showed maximum zone of inhibition against all of the nine pathogens tested. Strain KCA1 exhibited maximum level of antimicrobial metabolite production in solid state fermentation during 9 d of incubation. Three well separated spots were observed when the ethyl acetate extract of strain KCA1 was analyzed through thin-layer chromatography. One spot with retardation factor value 0.82 was found to inhibit Staphylococcus aureus in thin-layer chromatography bioautographic assay. The active fraction eluted from thin-layer chromatography was further characterized by gas chromatography-mass spectral analysis. The mass spectral data revealed the presence of three compounds viz., 2,4-di-tert-butylphenol (C14H22O), 1-hexadecanol (C16H34O) and 1-nonadecene (C19H38) present in major proportions which are responsible for the antimicrobial activity of the strain KCA1. In fermentation experiment, variables such as glucose, yeast extract and sodium chloride were found to influence the antimicrobial compound production. The potential strain KCA1 was identified as Streptomyces sp. on the basis of microscopic, cultural, physiological and 16S ribosomal ribonucleic acid analysis.

42 Feeding stalled horses a diet high omega-3 fatty acids results in a plasma fatty acid profile similar to horses on pasture

Omega-3 fatty acids (O-3) are a popular topic in equine nutrition, but it is not commonly acknowledged that a prevalent source of O-3 in a horse's diet can be from pasture. Pasture is low fat, but O-3 are the largest fraction, and horses on pasture have higher circulating O-3 than horses without pasture access. Therefore, the objective of these studies was to test the hypothesis that a feed high in O-3 that also matches the ratio of O-3:omega-6 (O-6) in pasture, would increase stalled horses’ plasma O-3 and result in a similar fatty acid profile to pastured horses. Three identical trials were completed between 2017 and 2020. Mature American Quarter Horses (n = 10 per trial; 610.5 ± 14 kg BW) were offered 0.9 kg per 454 kg BW Purina Omega Match Horse Feed (OM) and 2.0% BW Timothy hay split into equal meals (0700 a.m., 1300 p.m.) starting on d 1 of the trial. Horses were housed in individual stalls with attached dry lot turnouts for the duration of each study. The feed had a minimum of 3.5% O-3 with an O-3:O-6 ratio of 2.6. Baseline blood samples were obtained via jugular venipuncture into potassium oxalate tubes before transition to the experimental diet (d 0), and all horses were consuming a variety of other PurinaⓇ feeds before transition. Blood samples were collected on d 30 and 60 post dietary transition. Also, at d 60, blood samples were obtained from 10 horses each year at the Purina Animal Nutrition Center (Gray Summit, MO) that had free-choice access to mixed fescue pasture. These 10 horses were also fed 1.8 kg of Purina Strategy to meet nutritional needs and maintain body weight. All samples were obtained before AM feeding, were immediately centrifuged, and plasma collected for analysis. Fatty acids were analyzed via gas chromatographic-mass spectral analysis of fatty acid methyl esters. Data were analyzed using an ANOVA in SAS 9.4 (Cary, NC). All data are mean ± SD, ug/mL. Plasma O-3 levels increased from baseline (2.07 ± 0.54) to d 60 (6.29 ± 1.82) in horses consuming OM (P < 0.05). Conversely, plasma O-6 levels decreased from baseline (47.21 ± 3.86) to d 30 (42.56 ± 5.47) and remained lower at d 60 (43.89 ± 4.78) in horses consuming OM (P < 0.05). At d 60, horses consuming OM had similar plasma levels of O-3 (6.29 ± 1.82 vs 6.76 ± 2.01, P = 0.45) and O-6 (43.89 ± 4.78 vs 42.36 ± 5.80, P = 0.37) as horses on pasture, respectively. In conclusion, a feed formulated with a high level of O-3 can alter horses’ plasma O-3 concentrations until they match those of horses on pasture. This technique is helpful to boost horses’ O-3 values if they cannot tolerate pasture grass or simply do not have access to it.

Biocontrol of Colletotrichum falcatum with volatile metabolites produced by endophytic bacteria and profiling VOCs by headspace SPME coupled with GC–MS

A total of 49 endophytic bacteria isolated from sugarcane were screened in vitro for antagonistic property against C. falcatum through production of volatile organic compounds (VOCs). Among them, 27 bacteria produced volatiles with moderate inhibitory level, i.e. 30 to 50% and 9 produced volatiles with strong inhibitory properties, i.e. > 50% mycelial growth inhibition over control. The volatile compounds produced by B. axarquiensis—ESR 7 inhibited C. falcatum mycelia growth to the tune of 59.2% followed by B. licheniformis—ESR 26 (57.8%) and B. subtilis—ESR 24 (54.8%), respectively. The volatiles produced by bacteria not only inhibited the radial growth of mycelium but also suppressed the vertical expansion of mycelia and caused deformation in mycelia growth. The VOCs produced by 24 endophytic bacteria completely inhibited spore formation in C. falcatum culture. Profiling of antagonistic VOCs produced by bacterial strains ESR 7, ESR 24 and ESR 26 was done by head space-solid phase microextraction (SPME) coupled with gas chromatography mass spectral analysis. The analysis showed the presence of 63 compounds belonging to chemical groups of alcohols, esters, hydrocarbons, ketones, acids, amino acid, carbohydrates, ethers, aldehydes, amines and amides. Among the identified microbial volatiles, 6 compounds viz., acetic acid, methoxy-phenyl-oxime, octamethyl-cyclotetrasiloxane, 5,7-dimethyl-undecane, hexamethyl-cyclotrisiloxane and dodecane were reported in VOCs produced by all three bacteria. However, among 63 volatiles, only 31 were already reported to be produced by many bacteria and fungi and 11 compounds viz., acetic acid, hexanal, 2-ethyl-1-hexanol, undecane 5,7-dimethyl, undecane 3,7-dimethyl, 2-decanone, dodecane, 2-undecanone, 2-dodecanone, 1,2-Benzenedicarboxylic acid, diisooctyl ester and 2-methyl-hexadecanol were reported with antagonistic property against many plant pathogens. The study revealed that many VOCs produced by B. axarquiensis—ESR 7, B. subtilis—ESR 24 and B. licheniformis—ESR 26 play role in mediating antagonism against C. falcatum.

Analysis of the Essential Oils ofEucalyptus camaldulensisDehnh. andE. viminalisLabill. as a Contribution to Fortify Their Insecticidal Application

The use of synthetic chemicals, with harmful effects on the environment and human health, is the principal strategy in the management of stored-product insect pests such as Oryzaephilus surinamensis and Sitophilus oryzae. Various studies in recent years have highlighted the possibility of using plant essential oils as available and low-risk factors in insect pest management. Therefore, in the present study, the possibility of controlling O. surinamensis and S. oryzae was investigated using Eucalyptus camaldulensis and Eucalyptus viminalis leaf essential oils. The essential oils were obtained by hydrodistillation of the leaves of the 2 Eucalyptus species, and the chemical compositions were determined by gas chromatographic-mass spectral analysis. The essential oil of E. camaldulensis was dominated by p-cymene (24.8%), cryptone (18.9%), and spathulenol (12.4%), while the major components in E. viminalis essential oil were 1,8-cineole (51.6%) and α-pinene (15.8%). The essential oils displayed promising fumigant toxicity against insect pests, which was positively dependent on utilized concentrations and exposure times. Oryzaephilus surinamensis, with low median lethal concentrations, was more susceptible than S. oryzae to the essential oils after 24, 48, and 72 hours. Also, E. viminalis essential oil, with a high level of insecticidal monoterpenes such as 1,8-cineole and α-pinene, was more toxic to insect pests than E. camaldulensis oil. According to the results of the current study, E. camaldulensis and E. viminalis essential oils, rich in insecticidal terpenes, can be alternative candidates to synthetic chemicals in the management of O. surinamensis and S. oryzae.

Relative response of male Bactrocera frauenfeldi (Diptera: Tephritidae) to phenylbutanoid phytochemicals: implications for fruit fly control and plant–insect interactions

The interactions between Dacini male fruit flies and phytochemical male lures are unique. Lure response, fate and its effects after consumption on fruit fly mating behaviour are species- and lure-specific. Bactrocera frauenfeldi is known to respond to the phenylbutanoids raspberry ketone (RK) and cue lure (CL), anisyl acetone (AA), and zingerone (ZN), which are produced by some rainforest orchids. Here we compared the relative field responses of B. frauenfeldi males to these phenylbutanoids in two selected locations to determine the most attractive lure for this species. We also performed gas chromatographic-mass spectral analyses of male rectal pheromone glands to understand the fate of the ingested compounds. Results showed that B. frauenfeldi males were most responsive to CL, equally to RK and AA, while poorly to ZN in Cairns, a site with high population density. No significant difference was observed in Lockhart River which has a low population density of B. frauenfeldi. Chemical analyses showed that most of the ingested phenylbutanoids were sequestered into rectal glands, either unchanged or with minimal structural changes except for AA, which is converted to RK via a demethylation of the methoxy- to a hydroxy-moiety and reduced to 4-(4-methoxyphenyl)-2-butanol via the keto-moiety. This study provides both practical and ecological implications: it identified the most attractive lure, which is important for monitoring and management of B. frauenfeldi; and based on the relative responses, conversion and retention rates by B. frauenfeldi males, revealed the ecological significance of these phytochemical lures in plant-fruit fly co-evolution.

Unraveling the cause of white striping in broilers using metabolomics.

ABSTRACTWhite striping (WS) is a major problem affecting the broiler industry. Fillets affected by this myopathy present pathologies that compromise the quality of the meat, and most importantly, make the fillets more prone to rejection by the consumer. The exact etiology is still unknown, which is why a metabolomics analysis was performed on breast samples of broilers. The overall objective was to identify biological pathways involved in the pathogenesis of WS. The analysis was performed on a total of 51 muscle samples and distinction was made between normal (n = 19), moderately affected (n = 24) and severely affected (n = 8) breast fillets. Samples were analyzed using gas chromatographic mass spectral analysis and liquid chromatography quadrupole time-of-flight mass spectrometry. Data were subsequently standardized, normalized and analyzed using various multivariate statistical procedures. Metabolomics allowed for the identification of several pathways that were altered in white striped breast fillets. The tricarboxylic acid cycle exhibited opposing directionalities. This is described in literature as the backflux and enables the TCA cycle to produce high-energy phosphates through matrix-level phosphorylation and, therefore, produce energy under conditions of hypoxia. Mitochondrial fatty acid oxidation was limited due to disturbances in especially cis-5–14:1 carnitine (log2 FC of 2, P < 0.01). Because of this, accumulation of harmful fatty acids took place, especially long-chain ones, which damages cell structures. Conversion of arginine to citrulline increased presumably to produce nitric oxide, which enhances blood flow under conditions of hypoxia. Nitric oxide however also increases oxidative damage. Increases in taurine (log2 FC of 1.2, P < 0.05) suggests stabilization of the sarcolemma under hypoxic conditions. Lastly, organic osmolytes (sorbitol, taurine, and alanine) increased (P < 0.05) in severely affected birds; likely this disrupts cell volume maintenance. Based on the results of this study, hypoxia was the most likely cause/initiator of WS in broilers. We speculate that birds suffering from WS have a vascular support system in muscle that is borderline adequate to support growth, but triggers like activity results in local hypoxia that damages tissue.

ТЕРПЕНОИДЫ И ДРУГИЕ КОМПОНЕНТЫ ARTEMISIA SOGDIANA И A. SEROTINA, ПРОИЗРАСТАЮЩИХ В УЗБЕКИСТАНЕ

It was conducted the investigation of secondary metabolites by gas chromatography-mass spectral analysis of benzene extracts of the aerial parts of Artemisia sogdiana Bunge. and Artemisia serotina Bunge., collected during budding and early flowering spurs Nurata ridge Jizzakh region of Uzbekistan. The basic components of A. sogdiana are 5,5-dimethyl-2(5Н)-furanone – 17,99%, g-vinyl-g-valerolactone – 8,71%; monoterpenoids: 1,8-cineole – 28,13%, a-thujone – 3,18%, b- thujone – 2,69%, camphor – 8,65%, filifolide А – 4,05%, chrysanthenone – 5,23%.The basic components of A. serotina are 1,8-cineole – 10,08%, filifolide А – 8,62%, chrysanthenone – 13,00%, (Z)-jasmone – 1,95%.The represented in this report A. sogdiana and A. serotina both have available α-pinene, 5,5-dimethyl-2(5Н)-furanone, g-vinyl-g-valerolactone, 1,8-cineole, chrysanthenone, α-isophorone and filifolide А, which could be marker compounds for them.It should also be noted that the detected volatile monoterpenoids α- and β-thujones, camphor and 1,8-cineole are active inhibitors of seed germination and growth of seedlings of annual plants surrounding.The analysis identified 19 and 22 compounds of those Artemisia species for the first time, respectively.

Biological control of phytopathogenic bacteria Pantoea agglomerans and Erwinia chrysanthemi using 100 essential oils

Plants interact with a wide variety of pathogenic organisms by virtue of their sessile lifestyle. The Pantoea agglomerans and Erwinia chrysanthemi are major plant pathogen amongst them. They are known to cause significant losses in many crop plants. In the present study, bacteria isolated from infected Cajanus cajan and Arachis hypogaea seed are identified by 16S rDNA sequencing as P. agglomerans and E. chrysanthemi, respectively. In vitro antimicrobial properties of 100 essential oils (EOs) were evaluated against P. agglomerans and E. chrysanthemi. The chemical composition of most active EOs was investigated by gas chromatography–mass spectral analysis. The potential properties of these EOs as ecofriendly and economical biocontrol in agriculture is discussed.

Composition of the Essential Oil of Wild Growing Artemisia vulgaris from Erie, Pennsylvania

Essential oil from wild growing Artemisia vulgaris L. originating in Erie, Pennsylvania was obtained by hydrodistillation of the aerial parts of the plant. Gas chromatographic-mass spectral analysis was used to identify the major volatiles present. Up to 22 components were detected in the essential oils. Germacrene D (25%), Caryophyllene (20%), alpha-Zingiberene (15%) and Borneol (11%) represent the major components of leaf oil, while the buds were rich in 1,8-Cineole (32%), Camphor (16%), Borneol (9%), and Caryophyllene (5%). trans-2-Hexenal was also detected in the aerial parts of the plant. alpha-Zingiberene and trans-2-Hexenal have not been previously reported for Artemisia vulgaris L. The major analytes are compared to those from Artemisia vulgaris L, originating outside of the United States.

Variation in indoor levels of polycyclic aromatic hydrocarbons from burning various biomass types in the traditional grass-roofed households in Western Kenya

Biomass burning as fuel in the traditional grass-roofed rural households of Western Province of Kenya in open fire places, in poorly ventilated conditions, lead to accumulation of soot under the roofs. This study characterized and quantified the polycyclic aromatic hydrocarbons (PAHs) in accumulated soot in these households and determined the variation in PAHs concentrations with fuel biomass type. Soot samples collected from the households were extracted, cleaned and analysed by gas chromatography. The PAHs were identified using retention times, verified by gas chromatographic mass spectral analysis and quantified from peak area responses using the internal standard method. The PAHs levels significantly varied (P ≤ 0.05) with biomass type in the order: dung ≥ indigenous trees ≥ exotic trees ≥ shrubs and crop residues. Use of dung and wood from indigenous trees as fuel should be discouraged since they are higher emitters (P ≤ 0.05) of carcinogenic PAHs.

A method for concurrent diazomethane synthesis and substrate methylation in a 96-sample format

In the emerging field of metabolomics, there is an increasing need for improving sample derivatization reactions for gas chromatographic-mass spectral analysis of metabolites with large numbers of samples. This protocol details the safe direct derivatization of organic acids using diazomethane in a 96-sample format. Diazomethane is a highly reactive gas that readily forms methyl esters with carboxylic functionalities, with minimal side products or nonvolatile reaction residues. However, diazomethane's reactivity and explosive potential make it hazardous to store and work with. In this procedure, diazomethane is generated in situ and used concurrently to methylate up to 96 samples simultaneously, thus reducing concerns about reagent stability and obviating the need for storage of solutions of the highly reactive gas. Once the diazomethane generator has been assembled, processing 96 samples takes 2-3 h using this procedure.

Prebiotic chemistry: chemical evolution of organics on the primitive Earth under simulated prebiotic conditions

A series of prebiotic mixtures of simple molecules, sources of C, H, N, and O, were examined under conditions that may have prevailed during the Hadean eon (4.6-3.8 billion years), namely an oxygen-free atmosphere and a significant UV radiation flux over a large wavelength range due to the absence of an ozone layer. Mixtures contained a C source (methanol, acetone or other ketones), a N source (ammonia or methylamine), and an O source (water) at various molar ratios of C : H : N : O. When subjected to UV light or heated for periods of 7 to 45 days under an argon atmosphere, they yielded a narrow product distribution of a few principal compounds. Different initial conditions produced different distributions. The nature of the products was ascertained by gas chromatographic-mass spectral analysis (GC-MS). UVC irradiation of an aqueous methanol-ammonia-water prebiotic mixture for 14 days under low UV dose (6 x 10(-2) Einstein) produced methylisourea, hexamethylenetetramine (HMT), methyl-HMT and hydroxy-HMT, whereas under high UV dose (45 days; 1.9 x 10(-1) Einstein) yielded only HMT. By contrast, the prebiotic mixture composed of acetone-ammonia-water produced five principal species with acetamide as the major component; thermally the same mixture produced a different product distribution of four principal species. UVC irradiation of the CH(3)CN-NH(3)-H(2)O prebiotic mixture for 7 days gave mostly trimethyl-s-triazine, whereas in the presence of two metal oxides (TiO(2) or Fe(2)O(3)) also produced some HMT; the thermal process yielded only acetamide.

Identification of methyl farnesoate from in vitro culture of the retrocerebral complex of adult females of the moth, Heliothis virescens (Lepidoptera: Noctuidae) and its conversion to juvenile hormone III

Gas chromatographic-mass spectral analysis of extracts obtained from in vitro culture of isolated retrocerebral complexes obtained from adult females of the moth Heliothis virescens resulted in identification of methyl farnesoate as well as juvenile hormone III (JH III) but not JH III acid. Inhibition of JH biosynthesis by incubation of tissue in synthetic Manduca sexta allatostatin (Manse-AST, pGlu-Val-Arg-Phe-Arg-Gln-Cys-Tyr-Phe-Asn-Pro-Ile-Ser-Cys-Phe-COOH) reduced production of these chemicals to negligible levels. However, incubation of tissue in the presence of Manse-AST plus farnesol resulted in production of significant amounts of both methyl farnesoate and JH III. Tissue incubated in the presence of Manse-AST plus methyl farnesoate produced only JH III. The results indicated that methyl farnesoate is naturally produced by the corpora allata of adult females of Heliothis virescens. However, tissue incubated in the presence of Manse-AST plus JH III acid also produced JH III in amounts equivalent to that produced by tissue incubated with methyl farnesoate. Thus, both methyl farnesoate and JH III acid could serve as a precursor for biosynthesis of JH III.

Chain cleavage and sulfoxidation of thiastearoyl-ACP upon reaction with stearoyl-ACP desaturase.

The fatty acid analogues 9- and 10-thiastearate were converted to acyl-ACP derivatives by in vitro enzymatic synthesis and reacted with the reconstituted soluble stearoyl-ACP Delta9 desaturase complex. Electrospray ionization mass spectral analysis of the acyl chains purified from the reaction mixtures showed that 10-thiastearoyl-ACP was converted to the 10-sulfoxide as the sole product. In the presence of (18)O(2), the sulfoxide oxygen was found to be derived exclusively from O(2). This result confirms the ability of the soluble stearoyl-ACP desaturase to catalyze O atom transfer in the presence of the appropriate substrate analogue. Inhibition studies showed that 10-thiastearoyl-ACP was a mixed-type inhibitor of 18:0-ACP, with an apparent K(I) of approximately 10 microM. Comparable reactions of the stearoyl-ACP desaturase complex with 9-thiastearoyl-ACP gave the 9-sulfoxide as approximately 5% of the total products, with the O atom again exclusively derived from O(2). The remaining 95% of the total products arose from an acyl chain cleavage reaction between S-9 and C-10. Matrix-assisted laser desorption ionization time-of-flight mass spectral analysis showed that 9-thiastearoyl-ACP had a mass of 9443 amu while the acyl chain cleavage product had a mass of 9322 amu, corresponding to the calculated mass of 8-mercaptooctanoyl-ACP. Recovery of the acyl chain from the ACP product gave the disulfide of 8-mercaptooctanoate (mass of 349.1 amu), arising from the dimerization of 8-mercaptooctanoate during product workup. Gas chromatography-mass spectral analysis also showed the accumulation of nonanal in sealed reaction vials, accounting for the other product of the acyl chain cleavage reaction. The reactivity at both the 9 and 10 positions of the thia-substituted acyl-ACPs is consistent with the proximity of both positions to the diiron center oxidant in the enzyme-substrate complex. Moreover, the differential reactivity of the 9- and 10-thiastearoyl-ACPs also suggests position-dependent consequences of the reaction within the Delta9D active site. Mechanisms accounting for both sulfoxidation and acyl cleavage reactions by the stearoyl-ACP Delta9 desaturase are proposed.

In vitro induction of benzo(a)pyrene cell-transforming activity by the glucosinolate gluconasturtiin found in cruciferous vegetables

Cytotoxic and cell-transforming activity of gluconasturtiin (GNST), a promising chemopreventive agent commonly found in human diet, was studied in a medium-term bioassay utilizing BALB/c 3T3 cells. We also assessed whether GNST coupled with myrosinase, thus yielding product phenylethyl isothiocyanate (as shown by gas chromatography–mass spectral analysis), can affect the transforming potential of benzo(a)pyrene (B(a)P). Neither cytotoxicity nor cell-transforming activity was recorded. On the contrary, a marked increase (up to sevenfold) of the transforming activity of B(a)P was seen. This cocarcinogenic potential could be ascribed to an imbalance among bioactivation/detoxication during cell growth. These results indicate the need for an overall toxicological characterization of a chemopreventive agent prior to large-scale use.

Gas chromatography mass spectral analysis of free and glycosidically bound volatile compounds from Juniperus oxycedrus L. growing wild in Croatia

The essential oils in fresh needles and green and mature berries of Juniperus oxycedrus L. (Cupressaceae) were analyzed by GC–MS. A total of 36 compounds were identified from needles, representing 94.91% of the total oil. 15 compounds were identified in the green berry oil and 22 in the mature berry oil, which accounted for 94.33 and 90.94% of the total oil composition. The major component was α-pinene. The glycosidically bound volatile compounds amounted to 21 mg kg −1 in needles and 4 mg kg −1 from green berries. Only traces of aglycones were identified in mature berries. Sixteen volatile aglycones were identified in needle sample with 2-hydroxy-5-methylacetophenone as major component. A total of nine aglycones were identified in green berries. The major aglycones were 3-phenyl-2-propen-1-ol and myrtenol. There was no similarity between the glycosidically bound aglycones and the corresponding free compounds found in the essential oil.

Use of digital aroma technology and SPME GC-MS to compare volatile compounds produced by bacteria isolated from processed poultry

Digital aroma technology, solid-phase micro-extraction (SPME) and gas chromatographic mass spectral (GC-MS) analysis of the headspace volatile organic compounds were used to compare bacterial species important for food safety and common to biofilms in the poultry processing environment. The instrument for digital aroma technology, called the electronic nose, measured changes in resistance of polymer sensors caused by volatile gases from the headspace of samples. Graphical output by the Sammon mapping technique produced patterns of differences or similarities among the samples. Artificial neural network software was used to model groups of samples and classify subsequent unknowns. Compounds isolated from the headspace of sealed cultures using polydimethylsiloxane SPME fibres and identified by GC-MS analyses were predominantly alcohols and indole. These qualitative profiles were repetitive for specific organisms in relation to purity and repeatability of the cultures, differed by species and were used as objective standards to compare the graphical outputs of the electronic nose. © 1998 Society of Chemical Industry.

Use of digital aroma technology and SPME GC-MS to compare volatile compounds produced by bacteria isolated from processed poultry

Digital aroma technology, solid-phase micro-extraction (SPME) and gas chromatographic mass spectral (GC-MS) analysis of the headspace volatile organic compounds were used to compare bacterial species important for food safety and common to biofilms in the poultry processing environment. The instrument for digital aroma technology, called the electronic nose, measured changes in resistance of polymer sensors caused by volatile gases from the headspace of samples. Graphical output by the Sammon mapping technique produced patterns of differences or similarities among the samples. Artificial neural network software was used to model groups of samples and classify subsequent unknowns. Compounds isolated from the headspace of sealed cultures using polydimethylsiloxane SPME fibres and identified by GC-MS analyses were predominantly alcohols and indole. These qualitative profiles were repetitive for specific organisms in relation to purity and repeatability of the cultures, differed by species and were used as objective standards to compare the graphical outputs of the electronic nose. © 1998 Society of Chemical Industry.

Gas chromatography‐mass spectral analysis of roots of Echinacea species and classification by multivariate data analysis

An analytical method based on gas chromatography-mass spectral (GC-MS) analysis was developed as a fast screening tool in order to verify the authenticity of extracts of roots from different species of Echinacea, namely E. angustifolia, E. pallida and E. purpurea. Various extraction methods, i.e. soxhlet extraction, supercritical fluid extraction and maceration with three different solvents, were applied and the extracts were analysed by GC-MS. The chromatograms were evaluated by multivariate data analysis, i.e. cluster analysis, principal component analysis and discriminant analysis, in order to reveal if a classification into the three main species of Echinacea was possible using the information obtained. GC-MS analysis of the extracts of Echinacea, together with multivariate data analysis, displayed substantial classification power since a good separation of the three different species was achieved. This analytical approach was not only suitable for classification but was also sufficiently robust such that no distortion of root samples by ageing occurred. © 1998 John Wiley & Sons, Ltd.