Search results for "Chromatography-mass spectrometry"

Novel Source of Ubiquitous Phthalates as Analytical Contaminant

1981

Gas chromatography/mass spectrometry of catechol estrogens

1992

Abstract Catecholestrogens (CCEs), namely 2- or 4-hydroxyestradiol and hydroxyestrone, are highly polar, reactive, and extremely labile estrogen metabolites in many experimental conditions. For these reasons, indirect assay methods mainly have been used. Some experimental evidence suggests that CCEs are synthesized and biologically active mostly in target cells. At this level, unfortunately, the indirect assays cannot be used. We present a method of gas Chromatographic/mass spectral (GC/MS) analysis for the identification of individual CCEs; the major fragmentation ions of authentic estrogen standards as trimethylsilylether derivatives, and the MS patterns of the major CCEs, namely, 2-hydro…

Chemical composition of the essential oils of Centaurea formanekii and C. orphanidea ssp. thessala, growing wild in Greece.

2012

The volatile constituents of the aerial parts of Centaurea formanekii Halacsy and the aerial parts, capitula and roots of C. orphanidea Heldr. & Sart. ex Boiss. ssp. thessala (Hausskn.) Dostál from Greece were extracted by hydrodistillation and analyzed. The main components in C. formanekii were hexadecanoic acid (13.6%), δ-elemene (9.1%), and spathulenol (6.9%). The main components in C. orphanidea ssp. thessala were γ-elemene (26.1%) and caryophyllene oxide (13.2%) in the aerial parts, hexadecanoic acid (33.5%) and heptacosane (6.3%) in the capitula, and hexadecanoic acid methyl ester (22.0%) and α-chamigrene (14.0%) in the roots. The chemotaxonomic significance with respect to other…

Study of the influencing effect of pigments on the photoageing of terpenoid resins used as pictorial media

2006

Abstract Terpenoid resins have been mainly used as components of pictorial varnishes and binding media from ancient times. In such latest instances, the resin is mixed with pigments affecting its physical and chemical properties. A new procedure based on gas chromatography–mass spectrometry (GC/MS) has been applied, in this work, in combination with Fourier transform infrared spectroscopy (FTIR), with the aim of determining the changes undergone by di- and triterpenoid resins employed as components of binding media. The GC/MS method is based on the derivatisation of these resins using trimethylsilylimidazol. Characterization of the main components of the di- and triterpenoid fractions and t…

Identification of Volatile Compounds in Blackcurrant Berries: Differences Among Cultivars

2021

Berries of blackcurrant are known to produce a strong flavor. Some previous studies have reported that a given cultivar of blackcurrant can produce berries with a specific profile of volatile compounds. For the Burgundy region in France, the Noir de Bourgogne cultivar is especially important because it is the main ingredient of a liquor with a designation of origin. The aim of the present study was to characterize the volatile fractions of berries from 15 cultivars in order to explore the possibility of using different cultivars for liquor production. The plants were cultivated under the same conditions and harvested in the same year. The volatile fractions of the harvested berries were ana…

Chemical Composition Analysis, Antimicrobial Activity and Cytotoxicity Screening of Moss Extracts (Moss Phytochemistry)

2015

Mosses have been neglected as a study subject for a long time. Recent research shows that mosses contain remarkable and unique substances with high biological activity. The aim of this study, accordingly, was to analyze the composition of mosses and to screen their antimicrobial and anticancer activity. The total concentration of polyphenols and carbohydrates, the amount of dry residue and the radical scavenging activity were determined for a preliminary evaluation of the chemical composition of moss extracts. In order to analyze and identify the substances present in mosses, two types of extrahents (chloroform, ethanol) and the GC/MS and LC-TOF-MS methods were used. The antimicrobial activ…

Chemical composition of the essential oil of Salvia multicaulis Vahl. var. simplicifolia Boiss. growing wild in Lebanon

2004

The essential oil of aerial parts of Salvia multicaulis Vahl. var. simplicifolia Boiss. (Lamiaceae) growing wild in Lebanon was obtained by hydrodistillation and was analysed by GC and GC-MS. 67 compounds constituting 95.2% of the oil were identified, the major components being alpha-copaene (8.0%), alpha-pinene (6.6%), myrtenol (5.7%), trans-sabinyl acetate (5.3%).

Contribution to a Taxonomic Revision of the Sicilian Helichrysum Taxa by PCA Analysis of Their Essential-Oil Compositions

2016

The chemical profile of the essential oils in ten populations of the genus Helichrysum Mill. (Asteraceae), collected in the loci classici of the nomenclatural types of the taxa endemic to Sicily, were analyzed. Our results confirm that the analysis of secondary metabolites can be used to fingerprint wild populations of Helichrysum, the chemical profiles being coherent with the systematic arrangement of the investigated populations in three main clusters, referring to the aggregates of H. stoechas, H. rupestre, and H. italicum, all belonging to the section Stoechadina. The correct nomenclatural designation of the investigated populations is discussed and the following two new combinations ar…

The Seasonality Impact of the BTEX Pollution on the Atmosphere of Arad City, Romania

2021

Benzene, toluene, and total BTEX (benzene, toluene, ethylbenzene, and xylene) concentrations registered for one year (2016) have been determined every month for one high-density traffic area. The assessment was performed in Arad City, Romania, to evaluate these pollutants and their influence on the inhabitants’ health. The contaminants were sampled using a static sampling method and analyzed by gas chromatography coupled with mass spectrometry. Benzene was the most dominant among the BTEX compounds—the average concentrations ranged from 18.00 ± 1.32 µg m−3 in December to 2.47 ± 0.74 µg m−3 in August. The average toluene concentration over the year was 4.36 ± 2.42 µg m−3 (with a maximum of 9…

Phytoscreening as an efficient tool to delineate chlorinated solvent sources at a chlor-alkali facility

2017

Chlorinated ethenes (CE) are among the most common volatile organic compounds (VOC) that contaminate groundwater, currently representing a major source of pollution worldwide. Phytoscreening has been developed and employed through different applications at numerous sites, where it was generally useful for detection of subsurface chlorinated solvents. We aimed at delineating subsurface CE contamination at a chlor-alkali facility using tree core data that we compared with soil data. For this investigation a total of 170 trees from experimental zones was sampled and analyzed for perchloroethene (PCE) and trichloroethene (TCE) concentrations, measured by solid phase microextraction gas chromato…