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https://www.readbyqxmd.com/read/28937162/experimentally-validated-mathematical-model-of-analyte-uptake-by-permeation-passive-samplers
#1
F Salim, M Ioannidis, T Górecki
A mathematical model describing the sampling process in a permeation-based passive sampler was developed and evaluated numerically. The model was applied to the Waterloo Membrane Sampler (WMS), which employs a polydimethylsiloxane (PDMS) membrane as a permeation barrier, and an adsorbent as a receiving phase. Samplers of this kind are used for sampling volatile organic compounds (VOC) from air and soil gas. The model predicts the spatio-temporal variation of sorbed and free analyte concentrations within the sampler components (membrane, sorbent bed and dead volume), from which the uptake rate throughout the sampling process can be determined...
September 22, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28936871/effect-of-drying-moisture-exposed-almonds-on-the-development-of-the-quality-defect-concealed-damage
#2
Cristian Eduardo Rogel-Castillo, Kathleen K Luo, Guangwei Huang, Alyson Elayne Mitchell
Concealed damage (CD), is a term used by the nut industry to describe a brown discoloration of kernel nutmeat that becomes visible after moderate heat treatments (e.g. roasting). CD can result in consumer rejection and product loss. Postharvest exposure of almonds to moisture (e.g. rain) is a key factor in the development of CD as it promotes hydrolysis of proteins, carbohydrates and lipids. The effect of drying moisture-exposed almonds between 45°C - 95°C, prior to roasting was evaluated as a method for controlling CD in roasted almonds...
September 22, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28936271/comparison-of-the-volatile-organic-compound-recovery-rates-of-commercial-active-samplers-for-evaluation-of-indoor-air-quality-in-work-environments
#3
Yuichi Miyake, Masahiro Tokumura, Qi Wang, Zhiwei Wang, Takashi Amagai
The Industrial Safety and Health Law in Japan established administrative levels for volatile organic compounds (VOCs) in indoor air. In the present study, these 49 VOCs were extracted from the absorbents of commercial active samplers from Sibata Scientific Technology (carbon-bead active sampler), SKC Inc. (Anasorb CSC sorbent tube), and Gastec (bead-shaped activated carbon tube) using carbon disulfide, and the recovery rates were compared. The VOCs were added to the adsorbents at three concentration levels relative to the administrative levels (×0...
2017: Air Quality, Atmosphere, & Health
https://www.readbyqxmd.com/read/28935261/optimization-of-the-solvent-based-dissolution-method-to-sample-volatile-organic-compound-vapors-for-compound-specific-isotope-analysis
#4
Daniel Bouchard, Philipp Wanner, Hong Luo, Patrick W McLoughlin, James K Henderson, Robert J Pirkle, Daniel Hunkeler
The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant...
August 24, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28933773/rapid-quantification-of-major-volatile-metabolites-in-fermented-food-and-beverages-using-gas-chromatography-mass-spectrometry
#5
Farhana R Pinu, Silas G Villas-Boas
Here we present a method for the accurate quantification of major volatile metabolites found in different food and beverages, including ethanol, acetic acid and other aroma compounds, using gas chromatography coupled to mass spectrometry (GC-MS). The method is combined with a simple sample preparation procedure using sodium chloride and anhydrous ethyl acetate. The GC-MS analysis was accomplished within 4.75 min, and over 80 features were detected, of which 40 were positively identified using an in-house and a commercialmass spectrometry (MS) library...
July 26, 2017: Metabolites
https://www.readbyqxmd.com/read/28933109/-study-on-volatile-components-of-lonicerae-japonicae-flos-in-bud-stage-extended-type
#6
Jing-Ru Zhang, Gen-Ben Bai, Wei-Dong Li, Zhong-Shuang Zhang, Jin-Rui Gu, Cai-Qiao Zhang
Volatile components of Lonicerae Japonicae Flos in bud stage extended type Beihua 1 were determined by the headspace solid-phase micro-extraction, compared with traditional cultivar Damaohua. There are fifty-two volatile compounds were identified and the relative content of the volatiles was calculated by the area normalization method. Thirty-nine compounds were found in Beihua 1, whereas thirty-three components in Damaohua. Total twenty identical compounds existed in Beihua 1 and Damaohua. The contents of alcohols and hydrocarbons of Beihua 1 were higher significantly than that of Damaohua, while significantly lower than that of Damaohua in ketones content...
December 2016: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
https://www.readbyqxmd.com/read/28933107/-research-progress-of-chemical-constituents-and-pharmacological-activities-of-essential-oil-of-ligusticum-chuanxiong
#7
REVIEW
Jing-Chang Du, Xiao-Fang Xie, Liang Xiong, Chen Sun, Cheng Peng
Essential oil is the low polar and volatile components distilled or extracted from Ligusticum chuanxiong, the dry root of perennial herb L. chuanxiong, which has proven to be one of the main biological active ingredients of L. chuanxiong. Studies suggested that essential oil of L. chuanxiong mainly contains phthalide, terpene alcohols and fatty acids compounds. Different regions or varied extraction technology had influences on the type and contents of compound in essential oil of L. chuanxiong and the total yield efficiency of essential oil, while the differences among the distribution of compounds leads to the variant pharmacological function of essential oil of L...
December 2016: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
https://www.readbyqxmd.com/read/28932891/identification-of-terpenes-and-essential-oils-by-means-of-static-headspace-gas-chromatography-ion-mobility-spectrometry
#8
Roman Rodríguez-Maecker, Eduardo Vyhmeister, Stefan Meisen, Antonio Rosales Martinez, Andriy Kuklya, Ursula Telgheder
Static headspace gas chromatography-ion mobility spectrometry (SHS GC-IMS) is a relatively new analytical technique that has considerable potential for analysis of volatile organic compounds (VOCs). In this study, SHS GC-IMS was used for the identification of the major terpene components of various essential oils (EOs). Based on the data obtained from 25 terpene standards and 50 EOs, a database for fingerprint identification of characteristic terpenes and EOs was generated utilizing SHS GC-IMS for authenticity testing of fragrances in foods, cosmetics, and personal care products...
September 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28931931/screening-of-obstructive-sleep-apnea-syndrome-by-electronic-nose-analysis-of-volatile-organic-compounds
#9
Simone Scarlata, Giorgio Pennazza, Marco Santonico, Simona Santangelo, Isaura Rossi Bartoli, Chiara Rivera, Chiara Vernile, Antonio De Vincentis, Raffaele Antonelli Incalzi
Obstructive Sleep Apnea Syndrome (OSAS) carries important social and economic implications. Once the suspicion of OSAS has arisen, Polysomnography (PSG) represents the diagnostic gold standard. However, about 45% of people who have undergone PSG are free from OSAS. Thus, efforts should be made to improve the selection of subjects. We verified whether the pattern of Volatile Organic Compounds (VOCs) helps to select patients amenable to PSG. We studied 136 subjects (20 obese non-OSAS, 20 hypoxic OSAS, 20 non-hypoxic OSAS, and 20 non-hypoxic Chronic Obstructive Pulmonary Disease (COPD) vs 56 healthy controls) without any criteria of exclusion for comorbidity to deal with a real-life population...
September 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28930472/light-absorption-of-secondary-organic-aerosol-composition-and-contribution-of-nitro-aromatic-compounds
#10
Mingjie Xie, Xi Chen, Michael D Hays, Michael Lewandowski, John H Offenberg, Tadeusz Edward Kleindienst, Amara Holder
Secondary organic aerosol (SOA) might affect the atmospheric radiation balance through absorbing light at shorter visible and UV wavelengths. However, the composition and optical properties of light-absorbing SOA is poorly understood. In this work, SOA filter samples were collected during individual chamber experiments with three biogenic and eight aromatic volatile organic compound (VOC) precursors in the presence of NOX and H2O2. Compared with the SOA generated using the aromatic precursors, biogenic SOA in general exhibits negligible light absorption above 350 nm; the aromatic SOA generated in the presence of NOX showed stronger light absorption than that generated with H2O2...
September 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28930277/biological-activities-of-three-essential-oils-of-the-lamiaceae-family
#11
REVIEW
Gema Nieto
Herbs and spices have been used since ancient times to improve the sensory characteristics of food, to act as preservatives and for their nutritional and healthy properties. Herbs and spices are generally recognized as safe (GRAS) and are excellent substitutes for chemical additives. Essential oils are mixtures of volatile compounds obtained, mainly by steam distillation, from medicinal and aromatic plants. They are an alternative to synthetic additives for the food industry, and they have gained attention as potential sources for natural food preservatives due to the growing interest in the development of safe, effective, natural food preservation...
August 23, 2017: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28930245/antioxidant-and-antimicrobial-activities-of-the-essential-oil-of-achillea-millefolium-l-grown-in-france
#12
Chaker El-Kalamouni, Petras Rimantas Venskutonis, Bachar Zebib, Othmane Merah, Christine Raynaud, Thierry Talou
Background: This study aimed to examine the composition of essential oil (EO) of A. millefolium aerial parts wild plant grown in France and evaluate its antioxidant, antibacterial, and antifungal activities. Methods: GC-MS was used to identify the chemical composition of EO. Antioxidant activity (AA) of EO was evaluated by Oxipres method. Antimicrobial activity of EO was evaluated by Agar-well diffusion and a broth microdilution assay. Results: Forty-three volatile compounds were identified. Major compounds were camphor (12...
May 19, 2017: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28930244/characterization-and-antioxidant-activity-of-volatile-constituents-from-different-parts-of-aframomum-danielli-hook-k-schum
#13
Emmanuel E Essien, Paul S Thomas, Kelly Oriakhi, Mohammad I Choudhary
Background:Aframomum danielli is used in ethno-medicine for the treatment of several ailments and as a traditional food spice. Methods: The hydro-distilled leaf, stem, seed, rhizome and pod volatile oils of A. danielli were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. Free radical scavenging capacity of the volatile oils was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Results: Thirty-nine (39) volatile compounds were identified in the oils of A...
May 10, 2017: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28930243/traditional-small-size-citrus-from-taiwan-essential-oils-bioactive-compounds-and-antioxidant-capacity
#14
Min-Hung Chen, Kai-Min Yang, Tzou-Chi Huang, Mei-Li Wu
Background: The calamondin (Citrus microcarpa Bunge) and the kumquat (Fortunella crassifolia Swingle) are two small-size citrus fruits that have traditionally been consumed in Taiwan; however, there has been a lack of scientific research regarding the active compounds and functionalities of these fruits. Methods: Analysis of volatile composition of essential oil and phytosterol was carried out using Gas Chromatography-Mass Spectrometry (GC-MS). Flavonoid and limonoid were analyzed by High Performance Liquid Chromatography (HPLC)...
May 8, 2017: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28930239/eryngium-foetidum-l-essential-oils-chemical-composition-and-antioxidant-capacity
#15
Paul S Thomas, Emmanuel E Essien, Samuel J Ntuk, Mohammad I Choudhary
Background:Eryngium foetidum essential oils from Nigeria were investigated for the first time in order to ascertain their potency as natural antioxidants. E. foetidum is an aromatic and medicinal herb used in ethno-medicine and as a traditional spice for foods. Methods: The hydro-distilled oils of E. foetidum were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. Free radical scavenging capacity of the volatile oils was determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays...
April 28, 2017: Medicines (Basel, Switzerland)
https://www.readbyqxmd.com/read/28928759/identification-of-biomarkers-for-defense-response-to-plasmopara-viticola-in-a-resistant-grape-variety
#16
Giulia Chitarrini, Evelyn Soini, Samantha Riccadonna, Pietro Franceschi, Luca Zulini, Domenico Masuero, Antonella Vecchione, Marco Stefanini, Gabriele Di Gaspero, Fulvio Mattivi, Urska Vrhovsek
Downy mildew (Plasmopara viticola) is one of the most destructive diseases of the cultivated species Vitis vinifera. The use of resistant varieties, originally derived from backcrosses of North American Vitis spp., is a promising solution to reduce disease damage in the vineyards. To shed light on the type and the timing of pathogen-triggered resistance, this work aimed at discovering biomarkers for the defense response in the resistant variety Bianca, using leaf discs after inoculation with a suspension of P...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28928524/volatiles-formation-in-gelled-emulsions-enriched-in-polyunsaturated-fatty-acids-during-storage-type-of-oil-and-antioxidant
#17
Lucía Gayoso, Candelaria Poyato, María Isabel Calvo, Rita Yolanda Cavero, Diana Ansorena, Iciar Astiasarán
Gelled emulsions with carrageenan are a novel type of emulsion that could be used as a carrier of unsaturated fatty acids in functional foods formulations. Lipid degradation through volatile compounds was studied in gelled emulsions which were high in polyunsaturated oils (sunflower or algae oil) after 49 days of storage. Aqueous Lavandula latifolia extract was tested as a natural antioxidant. Analysis of the complete volatile profile of the samples resulted in a total of 40 compounds, classified in alkanes, alkenes, aldehydes, ketones, acids, alcohols, furans, terpenes and aromatic hydrocarbons...
August 2017: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/28926863/evaluation-of-cannabinoid-and-terpenoid-content-cannabis-flower-compared-to-supercritical-co2-concentrate
#18
Michelle Sexton, Kyle Shelton, Pam Haley, Mike West
A recent cannabis use survey revealed that 60% of cannabis users rely on smelling the flower to select their cannabis. Olfactory indicators in plants include volatile compounds, principally represented by the terpenoid fraction. Currently, medicinal- and adult-use cannabis is marketed in the United States with relatively little differentiation between products other than by a common name, association with a species type, and Δ-9 tetrahydrocannabinol/cannabidiol potency. Because of this practice, how terpenoid compositions may change during an extraction process is widely overlooked...
September 19, 2017: Planta Medica
https://www.readbyqxmd.com/read/28926195/non-targeted-volatile-profiles-for-the-classification-of-the-botanical-origin-of-chinese-honey-by-solid-phase-microextraction-and-gc-ms-combined-with-chemometrics
#19
Hui Chen, Linghe Jin, Chunlin Fan, Wenwen Wang
A potential method for the discrimination and prediction of honey samples of various botanical origins was developed based on the non-targeted volatile profiles obtained by solid-phase microextraction with gas chromatography and mass spectrometry combined with chemometrics. The blind analysis of non-targeted volatile profiles was carried out using solid-phase microextraction with gas chromatography and mass spectrometry for 87 authentic honey samples from four botanical origins (acacia, linden, vitex and rape)...
September 19, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28925699/ab-initio-computation-of-energy-deposition-during-electron-ionization-of-molecules
#20
Karl K Irikura
The dissociative ionization of molecules under electron impact forms the basis for analytical mass spectrometry of volatile compounds. It is also important in other situations, notably plasmas. Although qualitative theory for mass spectrometry was developed long ago, progress toward predictive theory has been slow. A major obstacle has been ignorance of the amount of energy deposited in the molecular ion, prior to its fragmentation. Here, we consider the Binary-Encounter Bethe (BEB) theory, which was originally developed for predicting total ionization cross sections...
September 19, 2017: Journal of Physical Chemistry. A
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