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Micro gas chromatograph

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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Jiwon Lee, Menglian Zhou, Hongbo Zhu, Robert Nidetz, Katsuo Kurabayashi, Xudong Fan
A photoionization detector (PID) is widely used as a gas chromatography (GC) detector. By virtue of its non-destructive nature, multiple PIDs can be used in multi-dimensional GC. However, different PIDs have different responsivities towards the same chemical compound with the same concentration or mass due to different aging conditions of the PID lamps and windows. Here, we carried out a systematic study regarding the response of 5 Krypton μPIDs in a 1 × 4-channel 2-dimensional μGC system to 7 different volatile organic compounds (VOCs) with the ionization potential ranging from 8...
June 20, 2016: Analyst
Maria Letizia Amadori, Gianluca Poldi, Sara Barcelli, Pietro Baraldi, Michela Berzioli, Antonella Casoli, Susanna Marras, Giulio Pojana, Giovanni C F Villa
This paper presents the results of a comprehensive diagnostic investigation carried out on five paintings (three wood panels and two paintings on canvas) by Lorenzo Lotto, one of the most significant artists of the Italian Renaissance in the first half of 16th century. The paintings considered belong to 1508-1522 period, corresponding to the most significant years of Lotto's evolution. A wide array of non-invasive (reflectance spectrometry and X-ray fluorescence) and micro-invasive analytical techniques (optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, micro-FTIR spectroscopy, micro-Raman spectroscopy, gas chromatography coupled with mass spectrometry and high performance liquid chromatography coupled with photodiode array detection and mass spectrometry) were applied in order to provide a large set of significant data, limiting as much as possible the sampling...
July 5, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jim Van Durme, Isabel Ingels, Ann De Winne
Today, the cocoa industry is in great need of faster and robust analytical techniques to objectively assess incoming cocoa quality. In this work, inline roasting hyphenated with a cooled injection system coupled to a gas chromatograph-mass spectrometer (ILR-CIS-GC-MS) has been explored for the first time to assess fermentation quality and/or overall aroma formation potential of cocoa. This innovative approach resulted in the in-situ formation of relevant cocoa aroma compounds. After comparison with data obtained by headspace solid phase micro extraction (HS-SPME-GC-MS) on conventional roasted cocoa beans, ILR-CIS-GC-MS data on unroasted cocoa beans showed similar formation trends of important cocoa aroma markers as a function of fermentation quality...
August 15, 2016: Food Chemistry
Francesca Patrignani, Fabio Chinnici, Diana I Serrazanetti, Pamela Vernocchi, Maurice Ndagijimana, Claudio Riponi, Rosalba Lanciotti
In wines, the presence of sulfur compounds is the resulting of several contributions among which yeast metabolism. The characterization of the starter Saccharomyces cerevisiae needs to be performed also taking into account this ability even if evaluated together with the overall metabolic profile. In this perspective, principal aim of this experimental research was the evaluation of the volatile profiles, throughout GC/MS technique coupled with solid phase micro extraction, of wines obtained throughout the fermentation of 10 strains of S...
2016: Frontiers in Microbiology
Wladimir Costa Paradas, Leonardo Tavares Salgado, Renato Crespo Pereira, Claire Hellio, Georgia Correa Atella, Davyson de Lima Moreira, Ana Paula Barbosa do Carmo, Angélica Ribeiro Soares, Gilberto Menezes Amado-Filho
We investigated the organelles involved in the biosynthesis of fatty acid (FA) derivatives in the cortical cells of Laurencia translucida (Rhodophyta) and the effect of these compounds as antifouling (AF) agents. A bluish autofluorescence (with emission at 500 nm) within L. translucida cortical cells was observed above the thallus surface via laser scanning confocal microscopy (LSCM). A hexanic extract (HE) from L. translucida was split into two isolated fractions called hydrocarbon (HC) and lipid (LI), which were subjected to HPLC coupled to a fluorescence detector, and the same autofluorescence pattern as observed by LSCM analyses (emission at 500 nm) was revealed in the LI fraction...
May 2016: Plant & Cell Physiology
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