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gas chromatography

Lanling Chu, Siwei Deng, Renshan Zhao, Jianjun Deng, Xuejun Kang
The objective of this study was to compare the adsorption/desorption of target compounds on homemade electrospun nanofibers, polystyrene (PS) nanofibers, acrylic resin (AR) nanofibers and PS-AR composite nanofibers with Tenax TA. Ten volatile organic compounds (VOCs) were analyzed by preconcentration onto different sorbents followed by desorption (thermal and solvent orderly) and analysis by capillary gas chromatography. In comparison to Tenax TA, the electrospun nanofibers displayed a significant advantage in desorption efficiency and adsorption selectivity...
2016: PloS One
Hongtao Guo, Xuyan Niu, Yan Gu, Cheng Lu, Cheng Xiao, Kevin Yue, Ge Zhang, Xiaohua Pan, Miao Jiang, Yong Tan, Hongwei Kong, Zhenli Liu, Guowang Xu, Aiping Lu
Pattern classification is a key approach in Traditional Chinese Medicine (TCM), and it is used to classify the patients for intervention selection accordingly. TCM cold and heat patterns, two main patterns of rheumatoid arthritis (RA) had been explored with systems biology approaches. Different regulations of apoptosis were found to be involved in cold and heat classification in our previous works. For this study, the metabolic profiling of plasma was explored in RA patients with typical TCM cold or heat patterns by integrating liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS) platforms in conjunction with the Ingenuity Pathway Analysis (IPA) software...
October 21, 2016: International Journal of Molecular Sciences
Bartosz Tylkowski, Martyna Nowak, Irene Tsibranska, Anna Trojanowska, Łukasz Marciniak, Ricard Garcia Valls, Tania Gumi, Marta Giamberini, Renata Jastrząb
BACKGROUND: This review aims to present the relevant background information and current research status in concentration of polyphenols using membrane technologies. The potential implementation of membrane separation to bioactive compounds like soluble phenolics from aqueous and organic solvent solutions is gaining increasing interest in the recent years. This review does not pretend to cover the abundant published literature on the subject, but to be representative for the observed tendencies in membrane processes applications for concentration of polyphenols derived from natural products...
October 21, 2016: Current Pharmaceutical Design
Ján Krupčík, Roman Gorovenko, Ivan Špánik, Daniel W Armstrong, Pat Sandra
The enantiomeric composition of several chiral markers in lavender essential oil was studied by flow modulated comprehensive two-dimensional gas chromatography operated in the reverse flow mode and hyphenated to flame ionization and quadrupole mass spectrometric detection. Two capillary column series were used in this study, 2,3-di-O-ethyl-6-O-tert-butyldimethylsilyl-β-cyclodextrin or 2,3,6-tri-O-methyl-β-cyclodextrin, as the chiral column in the first dimension and α polyethylene glycol column in the second dimension...
October 24, 2016: Journal of Separation Science
Sachiko Iizuka-Furukawa, Atsuko Isogai, Kazutaka Kusaka, Tsutomu Fujii, Yoshinori Wakai
The grassy characteristic aroma perceived in brewed sake made from low-glutelin rice (Oryza sativa L. Mizuhonoka) was examined by gas chromatography-olfactometry and gas chromatography-mass spectrometry. By comparing the odor properties and Kovats retention indices to those of standard compounds, 4-mercapto-4-methylpentan-2-one (4MMP) was found to contribute to the characteristic aroma. Sake brewing using Mizuhonoka, low-glutelin rice, and Gin-ohmi (a control) revealed that 4MMP concentrations in Mizuhonoka sake samples were higher than those in Gin-ohmi samples over the fermentation period...
October 20, 2016: Journal of Bioscience and Bioengineering
Fabrice Gritti, Michael Fogwill, Martin Gilar, Joseph A Jarrell
The rapid and complete baseline separation of both volatile (C5 to C16 alkanes in gasoline or terpenes in plant extracts) and non-volatile (>C20 alkanes) organic compounds was achieved by combining (1) low-density fluid chromatography (LDFC) using carbon dioxide at elevated temperature (>90°C) and low pressure (1500psi) designed to increase the retention of the most volatile compounds and (2) high-vacuum technology (<10(-4)Torr) in order to preserve the maximum efficiency of short analytical columns (3...
October 18, 2016: Journal of Chromatography. A
Yu-Hsuan Chen, Chia-Yu Chang, Wang-Hsien Ding
A simple and effective method for determining short chain chlorinated paraffins (SCCPs) in indoor dust is presented. The method employed a modified vortex-homogenized matrix solid-phase dispersion (VH-MSPD) prior to its detection by gas chromatography - electron-capture negative-ion mass spectrometry (GC-ECNI-MS) operating in the selected-ion-monitoring (SIM) mode. Under the best extraction conditions, 0.1-g of dust sample was dispersed with 0.1-g of silica gel by using vortex (2min) instead of using a mortar and pestle (3min)...
October 19, 2016: Journal of Chromatography. A
Shirin Babaee, Ali Daneshfar, Tahere Khezeli
Magnetically separable layered double hydroxide Ni/CuAl-LDH nanocomposites were synthesized and employed as ultrasonic-assisted dispersive micro-solid phase extraction (UA-D-μSPE) sorbent to extract several carboxylic acids (namely propionic, butyric, pentanoic, hexanoic, heptanoic, octanoic, and decanoic) from non-alcoholic beer samples. Ni/CuAl-LDH sorbent was characterized by Fourier transform-infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). Effective variables such as amount of sorbent (mg), pH and ionic strength of sample solution, volume of eluent solvent (μL), vortex, and ultrasonic times (min) were investigated via fractional factorial design (FFD)...
January 2017: Ultrasonics Sonochemistry
Jun Tabata, Ryoko T Ichiki
The cotton mealybug, Phenacoccus solenopsis, the distribution of which was formerly limited to Nearctic and Neotropical regions, recently invaded many countries in various regions including Asia, Africa, and the Pacific. More recently, P. solenopsis was newly recorded in Japan and is currently an emerging pest of agricultural crops. In this study, we determined the structure of a sex pheromone of P. solenopsis in order to develop an effective lure for monitoring this pest. From volatiles emitted by virgin adult females, we isolated a compound attractive to males...
October 22, 2016: Journal of Chemical Ecology
Jennifer Haggarty, Karl Ev Burgess
The metabolome is the complete complement of metabolites (small organic biomolecules). In order to comprehensively understand the effect of stimuli on a biological system, it is important to detect as many of the metabolites within that system as possible. This review briefly describes some new advances in liquid and gas chromatography to improve coverage of the metabolome, including the serial combination of two columns in tandem, column switching and different variations of two-dimensional chromatography...
October 20, 2016: Current Opinion in Biotechnology
Larissa Rangel Peixoto, Pedro Luiz Rosalen, Gabriela Lacet Silva Ferreira, Irlan Almeida Freires, Fabíola Galbiatti de Carvalho, Lúcio Roberto Castellano, Ricardo Dias de Castro
OBJECTIVE: The present study demonstrated the antifungal potential of the chemically characterized essential oil (EO) of Laurus nobilis L. (bay laurel) against Candida spp. biofilm adhesion and formation, and further established its mode of action on C. albicans. METHODS: L. nobilis EO was obtained and tested for its minimum inhibitory and fungicidal concentrations (MIC/MFC) against Candida spp., as well as for interaction with cell wall biosynthesis and membrane ionic permeability...
October 18, 2016: Archives of Oral Biology
Behrooz Alizadeh Behbahani, Fakhri Shahidi, Farideh Tabatabaei Yazdi, Seyed Ali Mortazavi, Mohebbat Mohebbi
In this study, Plantago major seed mucilage (PMSM) was extracted from whole seeds using hot-water extraction (HWE). The dill (D) essential oil components were identified through gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) and its antioxidant properties were examined through the methods of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant potential (FRAP) and ß-carotene-linoleic acid assay (B-CL). Total phenolic content (TPC) was characterized through the Folin-Ciocalteu method and the antimicrobial effect was evaluated on 10 pathogenic microorganisms...
October 19, 2016: International Journal of Biological Macromolecules
Tom F O'Callaghan, Hope Faulkner, Stephen McAuliffe, Maurice G O'Sullivan, Deirdre Hennessy, Pat Dillon, Kieran N Kilcawley, Catherine Stanton, R Paul Ross
This study evaluated the effects of 3 widely practiced cow feeding systems in the United States, Europe, and Southern Hemisphere regions on the characteristics, quality, and consumer perception of sweet cream butter. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a total mixed ration diet (TMR) of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass-only pasture (GRS); and group 3 was maintained outdoors on a perennial ryegrass/white clover pasture (CLV)...
October 19, 2016: Journal of Dairy Science
Campana Raffaella, Luca Casettari, Laura Fagioli, Marco Cespi, Giulia Bonacucina, Wally Baffone
Food safety is a fundamental concern for both consumers and the food industry, especially as the numbers of reported cases of food-associated infections continue to increase. Industrial surfaces can provide a suitable substrate for the development and persistence of bacterial organized in biofilms that represent a potential source of food contamination. The negative consumer perception of chemical disinfectants has shifted the attention to natural substances, such as plant extracts. The aim of this study was to investigate the possibility of using the essential oils (EOs) in the fight against S...
October 17, 2016: International Journal of Food Microbiology
Akiko Asada, Takahiro Doi, Takaomi Tagami, Akihiro Takeda, Yoshiyuki Sawabe
N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (APINACA) and N-(1-adamantyl)-1-pentyl-1H-indole-3-carboxamide (APICA) are carboxamide-type synthetic cannabinoids comprising indazole/indole-3-carboxylic acid and adamantan-1-amine moieties. However, in the case of compounds like APINACA or APICA, adamantyl positional isomers exist, wherein either adamantan-1-amine or adamantan-2-amine is present. These adamantyl positional isomers have not been reported in previous studies, and no analytical data are available yet...
October 21, 2016: Drug Testing and Analysis
Nur Nadia Mohamed, See Ling Loy, Che Nin Man, Abdullah Al-Mamun, Hamid Jan Jan Mohamed
OBJECTIVES: The objectives of this study are to determine parental and children's hair nicotine levels, their relationships as well as to investigate the association of smoking status of the fathers with mothers' and children's hair nicotine. METHODS: A cross-sectional study design was conducted among 124 families who were participants of the Universiti Sains Malaysia Pregnancy Cohort Study. Both parents with their 2 years old children joined this study. A total of 92 hair samples of fathers, 124 hair samples of mothers and 111 hair samples of children were collected and analyzed by gas chromatography-mass spectrometry...
October 21, 2016: Environmental Health and Preventive Medicine
Xiaxia Meng, Dengwu Li, Dan Zhou, Dongmei Wang, Qiaoxiao Liu, Sufang Fan
ETHNOPHARMACOLOGICAL RELEVANCE: Juniperus rigida is used as Tibetan and Mongolian medicine in China for the treatment of rheumatoid arthritis, nephritis, brucellosis and other various inflammatory diseases. AIM OF THE STUDY: To evaluate antibacterial potential of essential oils from J. rigida leaves against Klebsiella pneumoniae and to examine its possible related mechanisms. The study was undertaken in order to scientifically validate the traditional use of J. rigida...
October 18, 2016: Journal of Ethnopharmacology
Richard J Hamilton, Vadim Keyfes, Sahil S Banka
BACKGROUND: Synthetic cannabinoids (SC) are recreational designer drugs intended to mimic delta-9-tetrahydrocannabinol while surreptitiously circumventing classification by the Drug Enforcement Administration. CASE REPORT: A 50-year-old black male arrived in the Emergency Department transported by Emergency Medical Services (EMS) for altered mental status after complaining of chest pain associated with smoking SCs. EMS found the patient with an empty foil pack labeled "Scooby Snax Limited Edition Blueberry Potpourri...
October 19, 2016: Journal of Emergency Medicine
Siti Baidurah, Paramasivam Murugan, Lee Joyyi, Junya Fukuda, Masaya Yamada, Kumar Sudesh, Yasuyuki Ishida
Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of an organic alkali was validated for the compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] accumulated in whole bacterial cells. Recombinant Cupriavidus necator Re2058/pCB113 was grown in a batch fermentation with different concentration of palm oil and fructose in order to control the molar fraction of 3HHx in P(3HB-co-3HHx) produced in the cells. Trace amounts (30μg) of freeze-dried cells were directly subjected to THM-GC in the presence of tetramethylammonium hydroxide (TMAH) at 400°C...
October 14, 2016: Journal of Chromatography. A
Ji Ye Lee, Na Hyun Park, Wonwoong Lee, Eun Hye Kim, Young Ho Jin, Eun Kyung Seo, Jongki Hong
A comprehensive profiling method was established for the determination of various chemicals in Pinellia (P.) ternata and pedatisecta species. The profiling method comprises a fast ultrasonic extraction with various solvents, followed by GC-MS and LC-APCI-MS analysis. A total of 73 polar components as trimethylsilyl (TMS) derivatives were detected in methanol extract by GC-MS. The main components of the P. species were profiled as several kinds of fatty acids, amino acids, nucleic acids, carbohydrates, and phenolic compounds...
October 13, 2016: Journal of Chromatography. A
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