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Micro gas chromatograph

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https://www.readbyqxmd.com/read/29227020/determination-of-herbicides-in-environmental-water-samples-by-simultaneous-in-syringe-magnetic-stirring-assisted-dispersive-liquid-liquid-microextraction-and-silylation-followed-by-gc-ms
#1
Ruth Suárez, Sabrina Clavijo, Alba González, Víctor Cerdà
An on line, fast, simple, selective and sensitive method has been developed for the determination of three herbicides belonging to the following families: triazines (atrazine), chloroacetamide (alachlor) and phenoxy (2,4-dichlorophenoxyacetic acid) in water samples. The method involves an in-syringe magnetic stirring-assisted dispersive liquid-liquid microextraction along with simultaneous silylation prior to their determination by gas chromatography with mass spectrometry. Extraction, derivatization and preconcentration have been simultaneously performed using acetone as dispersive solvent, N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide as derivatization agent and trichloroethylene as extraction solvent...
December 11, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/29224338/dynamic-behavior-of-rh-species-of-rh-al2o3-model-catalyst-during-three-way-catalytic-reaction-an-operando-xas-study
#2
Hiroyuki Asakura, Saburo Hosokawa, Toshiaki Ina, Kazuo Kato, Kiyofumi Nitta, Kei Uera, Tomoya Uruga, Hiroki Miura, Tetsuya Shishido, Jun-Ya Ohyama, Atsushi Satsuma, Katsutoshi Sato, Akira Yamamoto, Satoshi Hinokuma, Hiroshi Yoshida, Masato Machida, Seiji Yamazoe, Tatsuya Tsukuda, Kentaro Teramura, Tsunehiro Tanaka
The dynamic behavior of Rh species in 1 wt% Rh/Al2O3 catalyst during the three-way catalytic reaction was examined using a micro gas chromatograph, a NOx meter, a quadrupole mass spectrometer, and time-resolved quick X-ray absorption spectroscopy (XAS) measurements at a public beamline for XAS, BL01B1 at SPring-8, operando. The combined data suggest different surface rearrangement behavior, random reduction processes, and autocatalytic oxidation processes of Rh species when the gas is switched from a reductive to an oxidative atmosphere and vice versa...
December 11, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29218109/rational-lung-tissue-and-animal-models-for-rapid-breath-tests-to-determine-pneumonia-and-pathogens
#3
Yong Zhou, Enguo Chen, Xiaohong Wu, Yanjie Hu, Huiqing Ge, Peifeng Xu, Yingchang Zou, Joy Jin, Ping Wang, Kejing Ying
OBJECTIVE: This study works to develop novel models that may be adopted for earlier non-invasive breathomics tests to determine pneumonia pathogens. METHODS: Two types of pneumonia models were created, both in vitro and in vivo. Paraneoplasm lung tissue and specific pathogen-free (SPF) rabbits were adopted and separately challenged with sterile saline solution control or three pathogens: Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. After inoculation, headspace air or exhaled air were absorbed by solid phase micro-extraction (SPME) fibers and subsequently analyzed with gas chromatograph Mass Spectrometer (GCMS)...
2017: American Journal of Translational Research
https://www.readbyqxmd.com/read/29178245/temperature-programmed-multi-capillary-gas-chromatograph-microcolumn-for-the-analysis-of-odorous-sulfur-pollutants
#4
Huan Yuan, Xiaosong Du, Huiling Tai, Ming Xu
We report the fabrication and performance of a silicon-on-glass micro gas chromatography eight-capillary column based on micro-electromechanical systems technology which is 50 cm long, 30 μm wide and 300 μm deep. According to the theory of a gas chromatography column, an even gas flow among different capillaries play a vital role in the peak broadening. Thus, a flow splitter structure is designed by the finite element method through the comparison of the velocity distributions of the eight-capillary columns with and without splitter as well as an open tubular column...
November 27, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/29150927/identification-of-proteins-drying-oils-waxes-and-resins-in-the-works-of-art-micro-samples-by-chromatographic-and-mass-spectrometric-techniques
#5
Bartłomiej Witkowski, Anna Duchnowicz, Monika Ganeczko, Agnieszka Laudy, Tomasz Gierczak, Magdalena Biesaga
Simplified method for simultaneous identification of proteins, drying oils, waxes and resins in the works-of-art samples was developed. Liquid chromatography with mass spectrometry and gas chromatography with mass spectrometry were used to identify natural materials most frequently encountered in historical paintings. Protein binders were extracted with ammonia and purified using miniaturized solid-phase microextraction (Omix tips) to efficiently suppress matrix interferences. Zwitterionic stationary phase was used for separation of sixteen underivatized amino acids analysis with hydrophilic interaction liquid chromatography that were subsequently quantified with liquid chromatography with mass spectrometry...
November 18, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28753000/an-easy-to-manufacture-micro-gas-preconcentrator-for-chemical-sensing-applications
#6
Mitchell M McCartney, Yuriy Zrodnikov, Alexander G Fung, Michael K LeVasseur, Josephine M Pedersen, Konstantin O Zamuruyev, Alexander A Aksenov, Nicholas J Kenyon, Cristina E Davis
We have developed a simple-to-manufacture microfabricated gas preconcentrator for MEMS-based chemical sensing applications. Cavities and microfluidic channels were created using a wet etch process with hydrofluoric acid, portions of which can be performed outside of a cleanroom, instead of the more common deep reactive ion etch process. The integrated heater and resistance temperature detectors (RTDs) were created with a photolithography-free technique enabled by laser etching. With only 28 V DC (0.1 A), a maximum heating rate of 17...
August 25, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28745351/atmospheric-concentrations-and-gas-particle-partitioning-of-polycyclic-aromatic-hydrocarbons-pahs-and-nitro-pahs-at-indo-gangetic-sites
#7
Puneet Kumar Verma, Dinesh Sah, K Maharaj Kumari, Anita Lakhani
Aerosol samples in the dual-phase (gaseous and particulate) were collected simultaneously for the first time in Agra at a rural and a traffic dominated site during post-monsoon and winter seasons to investigate the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). The samples were collected using a high volume sampler on quartz micro-fiber filter papers and polyurethane foam plugs for particulate and gas phases respectively. The samples were extracted in a mixture of DCM and n-hexane. 16 priority PAHs and two nitro-PAHs were analyzed using gas chromatograph-mass spectrometry...
August 16, 2017: Environmental Science. Processes & Impacts
https://www.readbyqxmd.com/read/28675034/electropolymerized-pyrrole-based-conductive-polymeric-ionic-liquids-and-their-application-for-solid-phase-microextraction
#8
Amila M Devasurendra, Cheng Zhang, Joshua A Young, L M Viranga Tillekeratne, Jared L Anderson, Jon R Kirchhoff
Pyrrole was covalently bonded to 1-methyl and 1-benzylimidazolium ionic liquids (ILs) via an N-substituted alkyl linkage to prepare electropolymerizable IL monomers with excellent thermal stability. The methylimidazolium IL, [pyrrole-C6MIm](+), was then electropolymerized on macro- and microelectrode materials to form conductive polymeric IL (CPIL)-modified surfaces. Electrochemical characterization of a 1.6 mm diameter Pt disk electrode modified with poly[pyrrole-C6MIm](+) demonstrated a selective uptake for an anionic redox probe while rejecting a cationic redox probe...
July 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28662852/ionic-liquid-functionalization-of-semi-packed-columns-for-high-performance-gas-chromatographic-separations
#9
Bishnu P Regmi, Ryan Chan, Masoud Agah
Gas chromatography columns fabricated using microelectromechanical system (MEMS) technology provide a number of clear advantages. However, successful deposition of stationary phases having a wide application range remains an important technical challenge. In this paper, we report, for the first time, on the deposition of room temperature ionic liquids (RTILs)-a versatile class of stationary phases-inside the channels of semi-packed columns (SPCs) for high-performance gas chromatographic separation of complex chemical mixtures...
August 11, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28535880/development-and-validation-of-a-novel-quantification-approach-for-gradient-elution-reversed-phase-high-performance-liquid-chromatography-coupled-to-tandem-icp-mass-spectrometry-rp-hplc-icp-ms-ms-and-its-application-to-diclofenac-and-its-related-compounds
#10
Balázs Klencsár, Lieve Balcaen, Filip Cuyckens, Frédéric Lynen, Frank Vanhaecke
A novel quantification approach, compensating for the effect of gradient elution on the instrumental response during reversed phase high-performance liquid chromatography - inductively coupled plasma - tandem mass spectrometry analysis, has been developed and validated. As a proof of concept, diclofenac and its related compounds, including its major metabolite i.e. 4'-hydroxy-diclofenac, have been quantitatively determined in human plasma matrix. An inductively coupled plasma - tandem mass spectrometer has been applied for the interference-free determination of Cl as (35)ClH2(+) using H2 as a reaction gas in the collision/reaction cell...
June 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28076838/identification-of-mdmb-fubinaca-in-commercially-available-e-liquid-formulations-sold-for-use-in-electronic-cigarettes
#11
Michelle R Peace, Rose I Krakowiak, Carl E Wolf, Alphonse Poklis, Justin L Poklis
MDMB-FUBINACA (aka MDMB(N)-Bz-F), chemical name Methyl (S)-2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3,3-dimethylbutanoate, a designer drug or a new psychoactive substance (NPS), was identified in three commercially available e-liquids formulated for electronic cigarette use. The e-liquids were evaluated using direct analysis in real time ion source attached to a time of flight mass spectrometer (DART-MS) and gas chromatograph mass spectrometer (GC-MS) to identify active ingredients/drugs, flavorants, and other possible constituents...
February 2017: Forensic Science International
https://www.readbyqxmd.com/read/27768075/combustion-characterization-and-model-fuel-development-for-micro-tubular-flame-assisted-fuel-cells
#12
Ryan J Milcarek, Michael J Garrett, Amrish Baskaran, Jeongmin Ahn
Combustion based power generation has been accomplished for many years through a number of heat engine systems. Recently, a move towards small scale power generation and micro combustion as well as development in fuel cell research has created new means of power generation that combine solid oxide fuel cells with open flames and combustion exhaust. Instead of relying upon the heat of combustion, these solid oxide fuel cell systems rely on reforming of the fuel via combustion to generate syngas for electrochemical power generation...
October 2, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27765417/electrodeposition-of-self-assembled-poly-3-4-ethylenedioxythiophene-gold-nanoparticles-on-stainless-steel-wires-for-the-headspace-solid-phase-microextraction-and-gas-chromatographic-determination-of-several-polycyclic-aromatic-hydrocarbons
#13
Liu Yang, Jie Zhang, Faqiong Zhao, Baizhao Zeng
In this work, a novel poly(3,4-ethylenedioxythiophene)@Au nanoparticles (PEDOT@AuNPs) hybrid coating was prepared and characterized. Firstly, the monomer 3,4-ethylenedioxythiophene was self-assembled on AuNPs, and then electropolymerization was performed on a stainless steel wire by cyclic voltammetry. The obtained PEDOT@AuNPs coating was rough and showed cauliflower-like micro-structure with thickness of ∼40μm. It displayed high thermal stability (up to 330°C) and mechanical stability and could be used for at least 160 times of solid phase microextraction (SPME) without decrease of extraction performance...
November 4, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27614975/determination-of-endocrine-disrupting-compounds-in-water-samples-by-magnetic-nanoparticle-assisted-dispersive-liquid-liquid-microextraction-combined-with-gas-chromatography-tandem-mass-spectrometry
#14
Rosa Ana Pérez, Beatriz Albero, José Luis Tadeo, Consuelo Sánchez-Brunete
A rapid extraction procedure is presented for the determination of five endocrine-disrupting compounds, estrone, ethinylestradiol, bisphenol A, triclosan, and 2-ethylhexylsalicylate, in water samples. The analysis involves a two-step extraction procedure that combines dispersive liquid-liquid microextraction (DLLME) with dispersive micro-solid phase extraction (D-μ-SPE), using magnetic nanoparticles, followed by in situ derivatization in the injection port of a gas chromatograph coupled to triple quadrupole mass spectrometry...
November 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27545394/vacuum-ultraviolet-absorption-spectroscopy-in-combination-with-comprehensive-two-dimensional-gas-chromatography-for-the-monitoring-of-volatile-organic-compounds-in-breath-gas-a-feasibility-study
#15
Beate Gruber, Thomas Groeger, Dale Harrison, Ralf Zimmermann
Vacuum ultraviolet (VUV) absorption spectroscopy was recently introduced as a new detection system for one, as well as comprehensive two-dimensional gas chromatography (GC×GC) and successfully applied to the analysis of various analytes in several matrices. In this study, its suitability for the analysis of breath metabolites was investigated and the impact of a finite volume of the absorption cell and makeup gas pressure was evaluated for volatile analytes in terms of sensitivity and chromatographic resolution...
September 16, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27525449/timing-in-analytical-pyrolysis-py-hmds-gc-ms-of-glucose-and-cellulose-using-online-micro-reaction-sampler
#16
Marco Mattonai, Diego Tamburini, Maria P Colombini, Erika Ribechini
A novel analytical approach based on pyrolysis-gas chromatography coupled with mass spectrometry of carbohydrates with in situ silylation using hexamethyldisilazane is presented in this work for the first time. A micro reaction sampler was used to simultaneously achieve the pyrolyis reaction and facilitate the derivatization of pyrolysis products, by enabling the materials to react with the derivatizing agent in a sealed capsule at high temperature and pressure for long periods of time. This drastically increased the complete silylation of the pyrolysis products and the chromatographic resolution, resulting in less complex pyrograms and increased sensitivity toward the most stable compounds...
September 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/27378248/the-gas-chromatographic-analysis-of-the-reaction-products-of-the-partial-isobutane-oxidation-as-a-two-phase-process
#17
Thomas Willms, Holger Kryk, Uwe Hampel
The partial oxidation of isobutane to t-butyl hydroperoxide (TBHP) has been studied analytically for the first time as a two-phase process in a capillary micro reactor. In order to obtain detailed information on products, yields, selectivities and reaction pathways, the products have been investigated by GC/MS. An Rxi-5ms column and a PTV-injector have been used to analyze the liquid products. TBHP, di-t-butyl peroxide (DTBP), t-butanol (TBA), and propanone as main products as well as further by-products e...
August 5, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/27262105/determination-of-n-alkanes-contamination-in-soil-samples-by-micro-gas-chromatography-functionalized-by-multi-walled-carbon-nanotubes
#18
Yubo Li, Runzhou Zhang, Tao Wang, Yonghuan Wang, Tianbai Xu, Lingfeng Li, Weijun Zhao, Shurong Dong, Xiaozhi Wang, Jikui Luo
A new method for separation of 11 n-alkanes: octane, o-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentdecne, n-hexadecath, heptadecane, n-octadecane in soil samples was developed. Kuderna-Danish (K.D.) concentrator enrichment prior to ultrasonic extraction and the silicone chromatography column purification and with gas chromatography flame ionization detection (GC-FID) could be used for n-alkanes determination. The micro channels of open tubular column were fabricated onto a silicon wafer to replace the quartz capillary chromatographic column...
September 2016: Chemosphere
https://www.readbyqxmd.com/read/27231039/sampling-of-btx-in-hat-yai-city-using-cost-effective-laboratory-built-pcb-passive-sampler
#19
Jas Raj Subba, Chongdee Thammakhet, Panote Thavarungkul, Proespichaya Kanatharana
A laboratory-built printed circuit board (PCB) passive sampler used for the monitoring of xylene and styrene in copy print shops was re-validated for detecting benzene, toluene and xylene (BTX) and applied for the sampling of ambient air from Hat Yai city, Songkhla, Thailand, in the month of November 2014. For monitoring, the PCB passive samplers were exposed to target analytes in 16 locations covering high to low exposure areas. After sampling, the samplers were thermally desorbed and the analytes were trapped by multi-walled carbon nanotubes packed into a micro-preconcentrator coupled to a gas chromatograph (GC) equipped with a flame ionization detector...
August 23, 2016: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/27154713/integrated-gas-chromatography-for-ultrafast-analysis-of-volatile-organic-compounds-in-air
#20
Yanggang Zhang, Dapeng Wu, Xiaohui Yan, Kun Ding, Yafeng Guan
An integrated instrumentation of a cryogenic microtrap-thermal desorption-low thermal mass (LTM) fast gas chromatographic (GC) system had been designed and evaluated for the ultrafast enrichment and separation of trace amounts of highly volatile organic compounds (VOCs) in air. The LTM fast GC column was wrapped uniformly on outer surface of a thin metal heating cylinder of 65mm O.D. and 0.5mm in thickness. Both of microtrap and LTM column could be rapidly cooled by liquid CO2 down to -35°C, and heated by resistive heating...
July 1, 2016: Talanta
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