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Analysis of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Adriana Arigò, Mariosimone Zoccali, Danilo Sciarrone, Peter Q. Tranchida, Paola Dugo, Luigi Mondello
Capillary gas chromatography is currently the method of choice for enantiomer analysis of essential oils, and enantioselective GC (Es-GC) has become an essential tool for stereochemical analysis, mainly after the introduction of cyclodextrin (CD) derivatives as chiral stationary phases (CSPs) in 1983 by Sybilska and Koscielski, at the University of Warsaw, for packed columns (Sybilska and Koscielski, 1983), and applied to capillary columns in the same decade (Schurig and Nowotny, 1988; König, 1991). Moreover, Nowotny et al. first proposed diluting CD derivatives in moderately polar polysiloxane (OV-1701) phases to provide them with good chromatographic properties and a wider range of operative temperatures (Nowotny et al., 1989).
Measurement of Exposure and Dose
Published in Samuel C. Morris, Cancer Risk Assessment, 2020
Each participant carried a personal air sampler throughout a normal 24-hour day, collecting two 12-h samples (a daytime sample and an overnight sample). Identical samplers were run in fixed locations in the backyard of one participant’s home in each of over 100 “clusters” to measure ambient air concentrations. At the end of the 24-h period, a sample of exhaled breath was collected from each participant. The study was conducted during three seasons (summer, fall, and winter), although samples were not taken in all cities during all three seasons. The air sampler was a glass cartridge containing a granular sorbent called Tenax-GC. The sampler was attached to a vest to hold it near the person’s breathing zone and air was pulled through the cartridge at 30 ml per minute by a small pump. Roughly 20 liters of air was pulled through the cartridge for each 12 h sample. The samples were analyzed by capillary gas chromatography mass spectrometry (GC-MS) techniques followed by a combination of manual and automated spectra analyses.
Toxicokinetics of Nerve Agents
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Marcel J. van der Schans, Hendrik P. Benschop, Christopher E. Whalley
Toxicokinetic studies were initiated in the last two decades of the last century. The reasons for the late development were two-fold. First, it was assumed that nerve agents react so quickly and are so rapidly degraded that it is impossible to measure these low levels of agent. Second, the expected levels were so low that the analytical capability was not sufficient to detect the nerve agent at relevant levels. With the advent of sophisticated sensitive analytical capabilities using capillary gas chromatography combined with sensitive detectors such as nitrogen phosphorus detection (NPD), flame photometric detection (FPD), and mass selective detection (MSD), it is possible to measure these extremely low levels of nerve agent. Moreover, there was reason to believe that the nerve agents might be more persistent than anticipated. Wolthuis et al. (1981) showed in 1982 that rats initially surviving a challenge with a supra-lethal dose of soman by immediate treatment with atropine and the oxime HI-6 became fatally re-intoxicated 4–6 h later. Hence, soman appeared to be far more persistent than anticipated. The persistence is even more pronounced in the case of percutaneous VX intoxication, which is caused by slow penetration through the skin and slow enzymatic hydrolysis. Especially in the case of intoxication with VX, toxicokinetic studies are of ultimate importance, because the time period of the intoxication might span several hours, which means that the timing of the antidote administration has to be adapted to the toxicokinetic process.
Role of 2.4 GHz radiofrequency radiation emitted from Wi-Fi on some miRNA and faty acids composition in brain
Published in Electromagnetic Biology and Medicine, 2022
Suleyman Dasdag, Mehmet Zulkuf Akdag, Mehmet Bashan, Veysi Kizmaz, Nurten Erdal, Mehmet Emin Erdal, Mehmet Tughan Kiziltug, Korkut Yegin
Fatty acid methyl esters were separated by capillary gas chromatography using a SHIMADZU GC 2010 PLUS equipped with a flame ionization detector (FID) and a fused silica capillary column (BP-21-Polyethylene Glycol (terephthalic acid treated)) (J & W Scientific, Folsom, CA, USA, 25 m × 0.32 mm internal diameter × 0.25 μm film thickness). Helium was used as the carrier gas. Gas flow rates: helium, 0.5 mL min−1; hydrogen, 30 mL min−1; dry air, 400 mL min−1. The temperature program used was as follows. The initial temperature (170°C) was kept for 8 min, raised to 190°C at a rate of 2°C min−1 and kept at 190°C for 17 min and raised to 220°C at a rate of 10°C min−1, and maintained at this temperature for 10 min. The injection and the detector temperatures were 250°C. The split ratio was 20/1. The FAMEs identification and quantification were performed through comparison of retention times (identification) and peak areas (quantification) with a calibration solution composed of a known quantity of each pure FAME (Sigma-Aldrich Chemicals, St., Louis, MO, USA). The amount of fatty acids was given as a percentage.
Cross-sectional association of seafood consumption, polyunsaturated fatty acids and depressive symptoms in two Torres Strait communities
Published in Nutritional Neuroscience, 2020
Maximus Berger, Sean Taylor, Linton Harriss, Sandra Campbell, Fintan Thompson, Samuel Jones, Maria Makrides, Robert Gibson, G. Paul Amminger, Zoltan Sarnyai, Robyn McDermott
Whole blood was collected on a validated dried blood spot system and fatty acid composition was analysed by capillary gas chromatography.30 Values for the following classes of LCPUFAs were obtained and included in the present analysis: Alpha-linolenic acid (18:3n-3), Eicosapentaenoic acid (20:5n-3), Docosapentaenoic acid (22:5n-3), Docosahexaenoic acid (22:6n-3), Linolenic acid (18:2n-6), Gamma-linolenic acid (18:3n-6), Eicosadienoic acid (20:2n-6), Dihomo-gamma-linolenic acid (20:3n-6), Arachidonic acid (20:4n-6), Docosadienoic acid (22:4n-6). The relative abundance (wt%) of these LCPUFAs was used for all analyses. We included the proportion of total n-3 LCPUFAs, the proportion of total n-6 LCPUFAs, the ratio between n-6 and n-3 LCPUFAs, and EPA and DHA separately due to their relevance to depression pathophysiology.
Isolation, characterisation and complement fixation activity of acidic polysaccharides from Argemone mexicana used as antimalarials in Mali
Published in Pharmaceutical Biology, 2022
Adama Dénou, Adiaratou Togola, Kari Tvete Inngjerdingen, Nastaran Moussavi, Frode Rise, Yuan Feng Zou, Dalen G. Dafam, Elijah I. Nep, Abubakar Ahmed, Taiwo E. Alemika, Drissa Diallo, Rokia Sanogo, Berit Smestad Paulsen
The monosaccharide compositions of the fractions were determined by gas chromatography of the trimethylsilylated (TMS) derivatives of the methyl-glycosides obtained after methanolysis with 3 M hydrochloric acid in anhydrous methanol for 24 h at 80 °C (Chambers and Clamp 1971; Barsett et al. 1992; Austarheim et al. 2012) (1 mg sample in 1 mL of 3 M hydrochloric acid in anhydrous methanol). Mannitol (100 µg) was used as an internal standard. The TMS derivatives were analysed by capillary gas chromatography on a Focus GC (Thermo Scientific, Milan, Italy).