Search results for "Gas chromatography–mass spectrometry"

A gas chromatography-mass spectrometric method to determine skin-whitening agents in cosmetic products.

2010

An analytical method is proposed here to determine three allowed (kojic acid, azelaic acid and arbutin) and two forbidden (resorcinol and hydroquinone) skin-whitening agents in cosmetics. The method is based on gas chromatography coupled with mass spectrometric detection, which allows the two prohibited target compounds to be identified unequivocally by means of their mass spectra acquired in full-scan mode at the retention time of these compounds. Owing to their low volatility, target analytes are derivatized using N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) (containing 1% trimethylchlorosylane) prior to injection into the chromatographic system. The accuracy and precision of the pr…

Chromatographic and mass spectrometric characteristics of 20-dihydroaldosterone.

1992

The 20 alpha-reduced derivative of aldosterone, 20 alpha-dihydroaldosterone, was needed as reference compound in order to continue the studies on 18-hydroxylation in the Y-1 adrenal cell line. It was obtained by reduction of aldosterone with sodium borohydride. Analysis of the products of the reaction as methoxime trimethylsilyl (MO-TMS) derivatives by gas chromatography (GC) and GC-mass spectrometry (GC-MS) showed three possible forms of the compound. Their identification was confirmed by comparison with the products obtained by stereospecific reduction of aldosterone using 3 alpha,20 beta-hydroxysteroid dehydrogenase. Chromatographic behavior and mass spectra are given for the three forms…

Gas chromatography-mass spectrometry characterization of the varnish and glue of an ancient 18th century double bass.

2007

A GC–MS investigation is conducted on the double bass “Panormus”, property of Conservatorio di Musica “Vincenzo Bellini” in Palermo. The most important components of the varnish (fatty acids) and of the glue (proteinaceous amino acids), with which the musical instrument was treated in the past, are determined. The analyses are carried out by prior derivatization of fatty acids by acidic methanol and of amino acids by acidic methanol and trifluoroacetic anhydride (TFAA). Analytes identification is achieved by direct comparison with several reference materials and the use of a digitized library.

Chromatographic Profiles of the main Secondary Metabolites in the Monarda fistulosa L. Aerial Part

2021

Two different methods of chromatographic analysis have been used in this study for the phytochemical evaluation of main secondary metabolites in the aerial part of bee balm (Monarda fistulosa L.) as the non-officinal medicinal plant of the Lamiaceae Martinov family. The high performance thin layer chromatography (HPTLC) fingerprinting method was developed for the qualitative analyses of phenolic and non-polar compounds in the bee balm herb after its maceration in the solvents of different polarity. Such polyphenols as rosmarinic, caffeic and chlorogenic acids were authentically identified in the methanol extract of herb using HPTLC. Aromatic monoterpenoid thymol was identified by the HPTLC …

2019

This paper describes data collected on 2 sets of 8 French red wines from two grape varieties: Pinot Noir (PN) and Cabernet Franc (CF). It provides, for the 16 wines, (i) sensory descriptive data obtained with a trained panel, (ii) volatile organic compounds (VOC) quantification data obtained by Headspace Solid Phase Micro-Extraction - Gas Chromatography - Mass Spectrometry (HS-SPME-GC-MS) and (iii) odor-active compounds identification by Headspace Solid Phase Micro-Extraction - Gas Chromatography - Mass Spectrometry - Olfactometry (HS-SPME-GC-MS-O). The raw data are hosted on an open-access research data repository [1].

Aroma characterization of freshly-distilled French brandies; their specificity and variability within a limited geographic area

2016

Freshly-distilled French wine brandies were evaluated by gas chromatography-olfactometry (GC-O). Six brandy samples were studied, coming from two growth areas, both belonging to the same limited geographic zone, which is a homogeneous vineyard area. The GC-O methodology, using detection frequency analysis, revealed 88 olfactive areas (OAs) for which the detection frequency was ≥ 25%. OAs were then identified using gas chromatography-mass spectrometry in electron and chemical ionization modes and semi-quantified by internal normalization using gas-chromatography with flame ionization detection. Co-eluting species were separated by multidimensional gas chromatography-mass spectrometry/olfacto…

Air monitoring of selected volatile organic compounds in wineries using passive sampling and headspace-gas chromatography–mass spectrometry

2014

Abstract Volatile compounds released during the production of wine at different steps of the winemaking process were evaluated using semipermeable membranes based passive samplers. Preliminary data on the differences between five wine varieties were provided together with the indoor quality of air to which winery workers are exposed during their professional activity. A simple, green and fast analytical methodology was employed for the direct analysis of deployed samplers by using head space (HS) gas chromatography–mass spectrometry (GC–MS) without any sample pre-treatment and avoiding the use of solvents. Terpenes as styrene, pinene, p-cymene and limonene were found at concentration levels…

Ancient wood of the Acqualadrone rostrum: Materials history through gas chromatography/mass spectrometry and sulfur X-ray absorption spectroscopy

2012

In 2008 the rostrum from an ancient warship was recovered from the Mediterranean near Acqualadrone, Sicily. To establish its provenance and condition, samples of black and brown rostrum wood were examined using sulfur K-edge X-ray absorption spectroscopy (XAS) and gas chromatography/mass spectrometry (GC/MS). GC/MS of pyrolytic volatiles yielded only guaiacyl derivatives, indicating construction from pinewood. A derivatized extract of black wood yielded forms of abietic acid and sandaracopimaric acid consistent with pine pitch waterproofing. Numerical fits to the sulfur K-edge XAS spectra showed that about 65% of the endogenous sulfur consisted of thiols and disulfides. Elemental sulfur was…

Pyrolysis-gas chromatography-mass spectrometry of cured phenolic resins.

2003

A previously described pyrolysis device with a movable reaction zone was used in the present work for thermal degradation of cured novolac and resol resins. After the pyrolysis the usual major components were identified, as well as relatively low-volatile aromatic compounds which were revealed after their separation in a capillary chromatographic column. Among the latter components, for both types of cured resins, xanthene and its methyl derivatives were found. The isomers of bis(hydroxyphenyl)methane were found in considerable quantities only in the case of partially cured novolac resins which contained any linear sequences in their structure.

Determination at low ppm levels of dithiocarbamate residues in foodstuff by vapour phase-liquid phase microextraction-infrared spectroscopy

2010

Abstract A methodology based on the vapour phase (VP) generation of carbon disulphide from non-volatile dithiocarbamate compounds has been developed for determination of pesticide residues in foodstuff at low ppm levels. The method involves a selective reaction combined with liquid phase microextraction (LPME) and transmission infrared measurements. The use of a home made transmission cell improved the detection limits (LOD) compared to the use of attenuated total reflectance measurements by a factor of approximately 80. Using the most appropriate experimental conditions for the CS2 generation and LPME preconcentration, the precision of the methodology, expressed as the relative standard de…