Search results for "Gas chromatography–mass spectrometry"

Multiresidue analysis of pesticides in honey by quechers and gas chromatography mass spectrometry in tandem

2011

Botanical Origin Authentication of Polish Phacelia Honey Using the Combination of Volatile Fraction Profiling by HS-SPME and Lipophilic Fraction Prof…

2019

Eleven samples of Polish Phacelia tanacetifolia Benth., three Brassica napus and one Salix spp. honeys were characterized by melissopalynology and analysis of the compositions of their volatile fractions. Headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME/GC–MS) using PDMS/CAR/DVB fiber was used for the isolation of low-molecular weight compounds which create a volatile fraction. To differentiate and indicate the most representative unifloral samples, chemometric techniques such as principal component analysis (PCA) and hierarchical-tree clustering (HTC) were applied to the dataset of the chromatographic fingerprints. Based on the obtained resul…

Polycyclic aromatic hydrocarbons (PAHs) in coffee brew samples: analytical method by GC-MS, profile, levels and sources.

2009

Roasting is a crucial step for the production of coffee, as it enables the development of color, aroma, and flavor, which are essential for the characterization of the coffee quality. At the same time, roasting may lead to the formation of not desirable compounds, such as polycyclic aromatic hydrocarbons (PAHs). In this paper, we report a method for PAHs determination in coffee brew, based on saponification and liquid-liquid extraction with small volumes of hexane, with exclusion of further processes of purification since we analyze the extract by gas chromatography with mass spectrometric detectors in the single ion monitoring mode (SIM). The total concentration of the 28 compounds investi…

Determination of usnic and perlatolic acids and identification of olivetoric acids in Northern reindeer lichen (Cladonia stellaris) extracts

2010

AbstractThe ecologically important lichen Cladonia stellaris forms thick carpets in boreal forest floors. In addition to affecting temperature and water conditions in the soil underneath, the secondary metabolites formed by the lichen layer are of ecological interest. In this paper, we investigated the distribution of lichen acids in C. stellaris collected at different latitudes in Finland and developed methods to quantify the two optical enantiomers of usnic acid separately. The lichen extracts were analysed by high-performance liquid chromatography (HPLC) with UV and mass spectrometric (MS) detection and by gas chromatography with flame ionization (GC-FID) and MS detection. Usnic acid and…

Essential oil analysis ofTeucrium libanitisandT. turredanumby GC and GC-MS

2003

The chemical composition of the six essential oils obtained from Teucrium libanitis and Teucrium turredanum collected at different localities was analysed by GC and GC–MS. Fifty-three constituents were identified. The oil of T. libanitis is characterized by the monoterpene α-pinene (9.9–21.2%) and the sesquiterpene δ-cadinene (5.3–9.7%), while that of T. turredanum had a higher content of sesquiterpenoids: β-caryophyllene (15.6–32.6%), α-humulene (4.7–10.1%) and β-bisabolol (6.4–8.3%), and a lower percentage of monoterpenoids (<1%). A multivariate procedure (hierarchical clustering) for detecting natural grouping established that T. libanitis and T. turredanum constitute two independent taxa…

Seasonal variations of antimicrobial activity and chemical composition of essential oils extracted from three Citrus limon L. Burm. cultivars

2014

In order to investigate the seasonal variations of antimicrobial properties and chemical composition of essential oils (EOs), three different cultivars of Citrus limon L. Burm. spp. (Femminello Santa Teresa, Monachello and Femminello Continella) were collected at 6-week intervals, from December 2012 to April 2013, for a total of four harvests. The EOs were extracted from lemon peel by hydro-distillation. The antimicrobial activity, tested by paper disc diffusion method, was evaluated against common food-related pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica and Enterobacter spp.). EOs were more effective against Gram-positive than Gram-negative bacte…

Volatile Compounds of Lemon and Grapefruit IntegroPectin

2020

An HS-SPME GC-MS analysis of the volatile compounds adsorbed at the outer surface of lemon and grapefruit pectins obtained via the hydrodynamic cavitation of industrial waste streams of lemon and grapefruit peels in water suggests important new findings en route to understanding the powerful and broad biological activity of these new pectic materials. In agreement with the ultralow degree of esterification of these pectins, the high amount of highly bioactive &alpha

Study on the effects of chemical cleaning on pinaceae resin-based varnishes from panel and canvas paintings using pyrolysis-gas chromatography/mass s…

2006

Abstract Cleaning of varnish coatings is one of the most critical steps in the restoration treatment of paintings and characterization of physical and chemical processes involved in this practical procedure has attracted interest of scientists in the field of conservation. Evaluation of chemical cleaning methods based on the application of organic solvents and detergents on Pinaceae resin-based varnishes from panel and canvas paintings has been successfully carried out using pyrolysis-gas chromatograpy/mass spectrometry (Py-GC/MS). The proposed method includes the on-line derivatization of the diterpenoid resin using hexamethyldisilazane (HMDS). Analyses performed on a series of model varni…

Analyses of known and new types of polyhalogenated aromatic substances in oven ash from recycled aluminium production

2003

Abstract Persistent aromatic bromine, chlorine and mixed chlorine-bromine compounds were analysed from recycled aluminium smelter (ALS) ashes to explore the impact of brominated flame retardants (BFR) on their formation. Polybrominated diphenyl ethers (PBDE) were the most abundant original BFRs found. Induction furnace ash contained tetra- to octa-BDEs about 2000 ng g −1 in similar congener ratios as the original scrap, but contents of nona- and deca-BDEs were only 25 and 5 ng g −1 indicating their significant degradation in ALS process. In the most non-polar fraction, PCB levels and profiles were similar as earlier ALS ash samples in 1990s. The highest PCB level measured was that of deca-C…

Analysis of LSD in human body fluids and hair samples applying ImmunElute columns.

2000

Immunoaffinity extraction units (LSD ImmunElute) are commercially available for the analysis of lysergic acid diethylamide (LSD) in urine. The ImmunElute resin contains immobilized monoclonal antibodies to LSD. We applied the ImmunElute procedure to serum and also to human hair samples. For hair analysis the samples were first extracted with methanol under sonication. The extracts were then purified using the ImmunElute resin. LSD analysis was carried out with HPLC and fluorescence detection. The immunoaffinity extraction provides highly purified extracts for chromatographic analysis. The limit of detection (signal-to-noise ratio = 3) has been determined to be < 50 pg regardless of which sa…