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https://www.readbyqxmd.com/read/28527332/determination-of-parabens-in-human-urine-by-optimal-ultrasound-assisted-emulsification-microextraction-and-on-line-acetylation-gas-chromatography-mass-spectrometry
#1
Zhou Hui-Ting, Erica M C Ding, Wang-Hsien Ding
An effective and solvent-less method for the rapid determination of four commonly detected parabens (methyl-, ethyl-, propyl- and butyl-) in human urine samples is described. This method employed ultrasound-assisted emulsification microextraction (USAEME) before identification and quantitation of the parabens via on-line acetylation gas chromatography-mass spectrometry (GC-MS). Urine samples were enzymatically de-conjugated with β-glucuronidase and then extracted by an optimal USAEME procedure for the measurement of total concentrations of target analytes...
May 10, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28527034/simultaneous-determination-of-selected-hormones-endocrine-disruptor-compounds-and-pesticides-in-water-medium-at-trace-levels-by-gc-ms-after-dispersive-liquid-liquid-microextraction
#2
Dotse Selali Chormey, Çağdaş Büyükpınar, Fatma Turak, Okan Tarık Komesli, Sezgin Bakırdere
The need to enhance food safety has led to major advancements in pesticide productions, and though many benefits have been gained, environmental contamination has also risen from these chemicals that tend to persist in the environment. Some pesticides, together with other chemicals commonly called endocrine disruptor compounds, block the receptor sites of hormones or mimic displaced hormones, leading to imbalanced hormonal levels that result in health disorders and diseases. These chemicals occur at trace levels and are not directly detected by conventional analytical methods...
June 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28527016/chemical-derivatization-of-metabolite-mass-profiling-of-the-recretohalophyte-aeluropus-lagopoides-revealing-salt-stress-tolerance-mechanism
#3
Murali Krishna Paidi, Parinita Agarwal, Prashant More, Pradeep K Agarwal
Plants are the primary producers of food for human being. Their intracellular environment alternation is influenced by abiotic stress factors such as drought, heat and soil salinity. Aeluropus lagopoides is a strong halophyte that grows with ease under high saline muddy banks of creeks of Gujarat, India. To study the response of salinity on metabolite changes in Aeluropus, three treatments, i.e. control, salinity and recovery, were selected for both shoot and root tissue. The cytosolic metabolite state was analysed by molecular chemical derivatization gas chromatography mass profiling...
May 19, 2017: Marine Biotechnology
https://www.readbyqxmd.com/read/28526637/identification-and-biological-activity-of-the-volatile-compounds-of-glycyrrhiza-triphylla-fisch-c-a-mey
#4
Abolfazl Shakeri, Javad Akhtari, Vahid Soheili, Seyedeh Faezeh Taghizadeh, Amirhossein Sahebkar, Rezvan Shaddel, Javad Asili
Chemical composition and biological (antimicrobial, antioxidant and cytotoxic) activities of essential oils (EO) obtained from the aerial parts of Glycyrrhiza triphylla Fisch. & C.A.Mey (G. triphylla) were evaluated in the present study. The EO was isolated and analyzed using gas chromatography-mass spectrometry (GC-MS). Fifty-five compounds representing 99.3% of the total oil composition were identified. Major components of the oil were β-caryophyllene (25.4%), limonene (16.7%), β-myrcene (16.0%) and α-humulene (4...
May 16, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28526084/liver-phospholipids-fatty-acids-composition-in-response-to-different-types-of-diets-in-rats-of-both-sexes
#5
Slavica Ranković, Tamara Popović, Jasmina Debeljak Martačić, Snježana Petrović, Mirko Tomić, Đurđica Ignjatović, Gordana Tovilović-Kovačević, Maria Glibetić
BACKGROUND: Dietary intake influence changes in fatty acids (FA) profiles in liver which plays a central role in fatty acid metabolism, triacylglycerol synthesis and energy homeostasis. We investigated the effects of 4-weeks treatment with milk- and fish-based diet, on plasma biochemical parameters and FA composition of liver phospholipids (PL) in rats of both sexes. METHODS: Adult, 4 months old, Wistar rats of both sexes, were fed with different types of diets: standard, milk-based and fish-based, during 4 weeks...
May 19, 2017: Lipids in Health and Disease
https://www.readbyqxmd.com/read/28525867/evaluation-of-alternative-environmentally-friendly-matrix-solid-phase-dispersion-solid-supports-for-the-simultaneous-extraction-of-15-pesticides-of-different-chemical-classes-from-drinking-water-treatment-sludge
#6
Karina Lotz Soares, Maristela Barnes Rodrigues Cerqueira, Sergiane Souza Caldas, Ednei Gilberto Primel
This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses...
May 12, 2017: Chemosphere
https://www.readbyqxmd.com/read/28525599/analytical-method-for-pyrethroid-metabolites-in-urine-of-the-non-occupationally-exposed-population-by-gas-chromatography-mass-spectrometry
#7
Toshiaki Yoshida
Pyrethroids are widely being used as household insecticides or mothproof repellents. An analytical method is described for determination of urinary metabolites as biomarkers for monitoring exposure to the pyrethroids. In total, 11 urinary metabolites, 3-(2-carboxyprop-1-enyl)-2,2-dimethylcyclopropanecarboxylic acid, 3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylic acid, 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid, 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid, 4-fluoro-3-phenoxybenzoic acid, 4-methoxymethyl-2,3,5,6-tetrafluorobenzly alcohol, 2-methyl-3-phenylbenzoic acid, 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol, 3-phenoxybenzoic acid, 2,3,5,6-tetrafluorobenzoic acid and 2,2,3,3-tetramethylcyclopropanecarboxylic acid, were enzymatically hydrolyzed and extracted with toluene...
May 19, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28525576/profiling-of-volatile-organic-compounds-produced-by-clinical-aspergillus-isolates-using-gas-chromatography-mass-spectrometry
#8
M G Gerritsen, P Brinkman, N Escobar, L D Bos, K de Heer, M Meijer, H-G Janssen, H de Cock, H A B Wösten, C E Visser, M H J van Oers, P J Sterk
Volatile organic compounds (VOCs) in exhaled breath may identify the presence of invasive pulmonary aspergillosis. We aimed to detect VOC profiles emitted by in vitro cultured, clinical Aspergillus isolates using gas chromatography-mass spectrometry (GC-MS). Three clinical Aspergillus isolates and a reference strain were cultured while conidiation was prevented. Headspace samples were analyzed using a standardized method. Breath samples of patients from which the cultures were obtained were checked for the presence of the VOCs found in vitro...
May 18, 2017: Medical Mycology: Official Publication of the International Society for Human and Animal Mycology
https://www.readbyqxmd.com/read/28524783/quantitative-analysis-of-veterinary-drugs-in-bovine-muscle-and-milk-by-liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry
#9
Shizuka Saito-Shida, Takatoshi Sakai, Satoru Nemoto, Hiroshi Akiyama
A simple and reliable multiresidue method for quantitative determination of veterinary drugs in bovine muscle and milk using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was developed. Critical MS parameters such as capillary voltage, cone voltage, collision energy, desolvation gas temperature, and extraction mass window were carefully optimised to obtain the best possible sensitivity. Analytical samples were prepared using extraction with acetonitrile and hexane in the presence of anhydrous sodium sulphate and acetic acid, followed by ODS cartridge clean-up...
May 19, 2017: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
https://www.readbyqxmd.com/read/28524084/bordetella-holmesii-lipid-a-structures-and-corresponding-genomic-sequences-comparison-in-three-clinical-isolates-and-the-reference-strain-atcc-51541
#10
Valérie Bouchez, Sami AlBitar-Nehmé, Alexey Novikov, Nicole Guiso, Martine Caroff
Bordetella holmesii can cause invasive infections but can also be isolated from the respiratory tract of patients with whooping-cough like symptoms. For the first time, we describe the lipid A structure of B. holmesii reference strain ATCC 51541 (alias NCTC12912 or CIP104394) and those of three French B. holmesii clinical isolates originating from blood (Bho1) or from respiratory samples (FR4020 and FR4101). They were investigated using chemical analyses, gas chromatography-mass spectrometry (GC-MS), and matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS)...
May 18, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28524080/cereus-sinensis-polysaccharide-and-its-immunomodulatory-properties-in-human-monocytic-cells
#11
Junwen Wu, Xuefei Zhou, Min Zhang, Yun Yao, Juanjuan Han, Kehai Liu
In this study, the extraction conditions of the crude polysaccharide from Cereus sinensis were optimized by response surface methodology. The optimum extraction conditions were: a ratio of raw material to water volume of 1:80 (g/mL); an extraction temperature of 72 °C; and an extraction time of 3 h. Then, a purified polysaccharide named Cereus sinensis polysaccharide-1 (CSP-1) was obtained from the crude polysaccharide by the Diethylaminoethyl cellulose-52 (DEAE-52) cellulose chromatography column and Sephadex G-100 column...
May 18, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28523515/distribution-of-exogenous-and-endogenous-cyp3a-markers-and-related-factors-in-healthy-males-and-females
#12
Jieon Lee, Andrew HyoungJin Kim, SoJeong Yi, SeungHwan Lee, Seo Hyun Yoon, Kyung-Sang Yu, In-Jin Jang, Joo-Youn Cho
Cytochrome P450 (CYP) 3A is an important drug-metabolizing enzyme in humans. Assessing CYP3A activity is necessary for predicting therapeutic outcomes or the potential adverse events of various therapeutics. This study sought to evaluate the distribution of endogenous and exogenous markers reflecting hepatic CYP3A activity and related factors affecting its activity in healthy male and female. Each subject was given a single 1 mg dose of midazolam intravenously. Pharmacokinetics, pharmacometabolomics, and pharmacogenomics analyses were performed to evaluate CYP3A activity...
May 18, 2017: AAPS Journal
https://www.readbyqxmd.com/read/28523505/mass-spectrometry-imaging-of-drugs-of-abuse-in-hair
#13
Bryn Flinders, Eva Cuypers, Tiffany Porta, Emmanuel Varesio, Gérard Hopfgartner, Ron M A Heeren
Hair testing is a powerful tool routinely used for the detection of drugs of abuse. The analysis of hair is highly advantageous as it can provide prolonged drug detectability versus that in biological fluids and chronological information about drug intake based on the average growth of hair. However, current methodology requires large amounts of hair samples and involves complex time-consuming sample preparation followed by gas or liquid chromatography coupled with mass spectrometry. Mass spectrometry imaging is increasingly being used for the analysis of single hair samples, as it provides more accurate and visual chronological information in single hair samples...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28522166/development-and-validation-of-a-simplified-titration-method-for-monitoring-volatile-fatty-acids-in-anaerobic-digestion
#14
Hao Sun, Jianbin Guo, Shubiao Wu, Fang Liu, Renjie Dong
The volatile fatty acids (VFAs) concentration has been considered as one of the most sensitive process performance indicators in anaerobic digestion (AD) process. However, the accurate determination of VFAs concentration in AD processes normally requires advanced equipment and complex pretreatment procedures. A simplified method with fewer sample pretreatment procedures and improved accuracy is greatly needed, particularly for on-site application. This report outlines improvements to the Nordmann method, one of the most popular titrations used for VFA monitoring...
May 15, 2017: Waste Management
https://www.readbyqxmd.com/read/28521980/sulphated-polysaccharide-isolated-from-sargassum-vulgare-characterization-and-hypolipidemic-effects
#15
Rihab Ben Abdallah Kolsi, Hichem Ben Salah, Neila Jardak, Rim Chaaben, Imed Jribi, Abdelfattah El Feki, Tarak Rebai, Kamel Jamoussi, Noureddine Allouche, Cristophe Blecker, Hafedh Belghith, Karima Belghith
A sulphated polysaccharide from brown algae Sargassum vulgare (SVSP) was extracted and examined with respect to chemical, structural characterization and hypolipidemic effects. SVSP consisted mainly of sulphate and total sugars with low levels of lipids and proteins. Its structure was studied by nuclear magnetic resonance (RMN), gas chromatography-mass spectrometry (GC-MS), infra-red spectroscopic, differential scanning calorimetry and X-ray diffraction analysis. Allowing us therefore to revealed that SVSP was composed of glucose, rhamnose, xylose, galactose, mannose and arabinose with XRD pattern that was typical for a semi-crystalline polymer and complexities of the spectra reflected its homogeneous structure...
August 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28521954/gas-chromatography-mass-spectrometry-strategies-for-the-accurate-and-sensitive-speciation-of-sulfur-dioxide-in-wine
#16
Vanesa Carrascon, Ignacio Ontañón, Mónica Bueno, Vicente Ferreira
Understanding the chemistry of wine oxidation requires the accurate and sensitive quantitative determination of the most important molecular species which SO2 can form. An analytical strategy based in three independent static headspace GC-MS determinations is proposed in order to obtain information about the total, nominally free and truly free levels of SO2. Nominally free forms are directly determined after sample acidulation, total forms require the previous incubation at 100°C, and truly free forms are determined after preconcentration of the headspace of the undisturbed sample in an alkaline solution...
May 8, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28521812/radiotherapy-improves-serum-fatty-acids-and-lipid-profile-in-breast-cancer
#17
Sana Shaikh, Naseem Aslam Channa, Farha Naz Talpur, Muhammad Younis, Naila Tabassum
BACKGROUND: Breast cancer is a disease with diverse clinical symptoms, molecular profiles, and its nature to response its therapeutic treatments. Radiotherapy (RT), along with surgery and chemotherapy is a part of treatment in breast cancer. The aim of present study was to investigate pre and post treatment effects of radiotherapy in serum fatty acids and its lipids profile in patients with breast cancer. METHODS: In this comparative as well as follow up study, Serum fatty acids were performed by gas chromatography to investigate fatty acids and Microlab for analysis of lipid profile...
May 18, 2017: Lipids in Health and Disease
https://www.readbyqxmd.com/read/28520922/gc-ms-method-for-quantification-of-mephedrone-in-human-blood-sample
#18
Khaled M Mohamed
Abuse of mephedrone (4-methylmethcathinone) has emerged among the last few years. Intoxication and fatality associated with mephedrone have been reported in the literature. The present work describes a simple and rapid gas chromatography-mass spectrometry (GC-MS) method for detection and quantification of mephedrone in human blood samples using GC-MS. Blood was deproteinated with acetonitrile and the supernatant was derivatized and extracted in a single step with ethyl chloroformate and ethyl acetate. Methamphetamine-d5 was used as an internal standard (IS)...
May 18, 2017: Journal of Chromatographic Science
https://www.readbyqxmd.com/read/28520815/metabolic-profiling-by-gas-chromatography-mass-spectrometry-of-energy-metabolism-in-high-fat-diet-fed-obese-mice
#19
Daxesh P Patel, Kristopher W Krausz, Cen Xie, Diren Beyoğlu, Frank J Gonzalez, Jeffrey R Idle
A novel, selective and sensitive single-ion monitoring (SIM) gas chromatography-mass spectrometry (GCMS) method was developed and validated for the determination of energy metabolites related to glycolysis, the tricarboxylic acid (TCA) cycle, glutaminolysis, and fatty acid β-oxidation. This assay used N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA) containing 1% tert-butyldimethylchlorosilane (TBDMCS) as derivatizing reagent and was highly reproducible, sensitive, specific and robust. The assay was used to analyze liver tissue and serum from C57BL/6N obese mice fed a high-fat diet (HFD) and C57BL/6N mice fed normal chow for 8 weeks...
2017: PloS One
https://www.readbyqxmd.com/read/28520742/experimental-outgassing-of-toxic-chemicals-to-simulate-the-characteristics-of-hazards-tainting-globally-shipped-products
#20
Lygia Therese Budnik, Nadine Austel, Sabrina Gadau, Stefan Kloth, Jens Schubert, Harald Jungnickel, Andreas Luch
Ambient monitoring analyses may identify potential new public health hazards such as residual levels of fumigants and industrial chemicals off gassing from products and goods shipped globally. We analyzed container air with gas chromatography coupled to mass spectrometry (TD-2D-GC-MS/FPD) and assessed whether the concentration of the volatiles benzene and 1,2-dichloroethane exceeded recommended exposure limits (REL). Products were taken from transport containers and analyzed for outgassing of volatiles. Furthermore, experimental outgassing was performed on packaging materials and textiles, to simulate the hazards tainting from globally shipped goods...
2017: PloS One
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