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Wei Liu, Jichun Jiang, Keyong Hou, Weiguo Wang, Yachen Qi, Yan Wang, Yuanyuan Xie, Lei Hua, Haiyang Li
Chlorinated benzenes are typical precursors and indicators for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emissions from waste incinerators. Online and real-time monitoring of chlorobenzenes is a challenge due to their low concentration and complex nature of the flue gas. In this work, a continuous online monitoring system was built for detection of trace chlorinated benzenes based on a time-of-flight mass spectrometer (TOFMS). A single photon ionization (SPI) source based on a radiofrequency-excited windowless vacuum ultraviolet (VUV) lamp was developed for the first time to eliminate the signal attenuation resulting from the contamination of magnesium fluoride windows and to avoid the fragment ions...
December 1, 2016: Talanta
Chris E Freye, Robert E Synovec
A high temperature diaphragm valve-based two-dimensional (2D) gas chromatography (GC×GC) with time-of-flight mass spectrometry (TOFMS) instrument, with the valve mounted directly in the GC oven, is demonstrated with separations up to 325°C. Use of the diaphragm valve allowed for the use of uncoupled carrier gas flows for (1)D (first column dimension) and (2)D (second column dimension), with a (1)D flow rate of 1ml/min, and a (2)D flow rate 3ml/min. The 3ml/min flow rate on (2)D was selected to ensure compatibility with most TOFMS detectors...
December 1, 2016: Talanta
Du Toit Loots, Conrad C Swanepoel, Mae Newton-Foot, Nicolaas C Gey van Pittius
The ESX-1 gene cluster, encoding the Type-VII secretion (T7S) system and its virulence associated proteins, ESAT-6 and CFP-10, is thought to be responsible for the transport of extracellular proteins across the hydrophobic and highly impermeable, cell envelope of Mycobacterium, and is involved in virulence in Mycobacterium tuberculosis, the causative agent of tuberculosis. Using a GCxGC-TOFMS metabolomics approach, a M. smegmatis ESX-1 knock-out strain (ΔESX-1ms) was compared to that of the M. smegmatis wild-type parent strain, and the metabolite markers due to the presence or absence of the ESX-1 gene cluster were identified...
October 12, 2016: Microbial Pathogenesis
Lin Qiao, Lirong Gao, Dan Xia, Huiting Huang, Minghui Zheng
Chlorinated paraffins (CPs) are easily adsorbed into sediments where they pose potential risks to the ecosystem and human health. Few studies have investigated short- and medium-chain CPs (SCCPs and MCCPs) in sediments. The aim of the present study was to comprehensively investigate contamination levels, spatial distributions, sources and risks posed by CPs in sediments from the middle reaches of the Yangtze River. The sediment samples were analyzed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS)...
September 30, 2016: Science of the Total Environment
S K Lengger, J Fromont, K Grice
Over 8600 species are currently recorded in the phylum Porifera (sponges). They produce a large diversity of biochemical compounds including sterols, with more than 250 different sterols identified. Some of these sterols are of great interest, due to their use for fingerprinting in ecological and biomarker (molecular fossil) studies. As a large number of identified extant species from biodiversity surveys are housed in museum collections, preserved in ethanol, these present a potentially rich source of identified specimens for comparative lipid analyses...
September 29, 2016: Geobiology
Shuhei Miura, Tomohiro Uchimura
We describe a new technique for evaluating the translational temperature of molecules by applying online concentration via analyte adsorption/laser desorption, which is a sample-introduction technique for resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS). In the present study, analyte molecules were adsorbed via a narrowed capillary tip once, and then the flow of the carrier gas containing the analyte was stopped. After laser desorption, the ion signals induced by REMPI were monitored...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Yuki Kageyama, Takaoki Kasahara, Hiromasa Morishita, Nobuko Mataga, Yasuhiko Deguchi, Munehide Tani, Kenji Kuroda, Kotaro Hattori, Sumiko Yoshida, Koki Inoue, Tadafumi Kato
AIMS: There is an urgent need for diagnostic biomarkers of bipolar disorder (BD) and schizophrenia (SZ); however, confounding effects of medication on hamper biomarker discovery. In this study, we conducted metabolome analyses to identify novel plasma biomarkers in drug-free patients with BD and SZ. METHODS: We comprehensively analyzed plasma metabolites using capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS) in patients with SZ (n = 17), BD (n = 6), and major depressive disorder (n = 9), who had not received psychotropics for at least two weeks, and in matched healthy controls (n = 19)...
September 27, 2016: Psychiatry and Clinical Neurosciences
Akitomo Shibata, Yu Ishima, Mayumi Ikeda, Hirokazu Sato, Tadashi Imafuku, Victor T G Chuang, Yuya Ouchi, Takaya Abe, Hiroshi Watanabe, Tatsuhiro Ishida, Masaki Otagiri, Toru Maruyama
Recently, hydropersulfide (RSSH) was found to exist in mammalian tissues and fluids. Cysteine hydropersulfide can be found in free cysteine residues as well as in proteins, and it has potent antioxidative activity. Human serum albumin (HSA) is the most abundant protein in mammalian serum. HSA possesses a free thiol group in Cys-34 that could be a site for hydropersulfide formation. HSA hydropersulfide of high purity as a positive control was prepared by treatment of HSA with Na2S. The presence of HSA hydropersulfide was confirmed by spectroscopy and ESI-TOFMS analysis where molecular weights of HSA hydropersulfide by increments of approximately 32 Da (Sulfur atom) were detected...
October 21, 2016: Biochemical and Biophysical Research Communications
Kazuhiko Uchiyama, Nobuaki Yagi, Katsura Mizushima, Yasuki Higashimura, Yasuko Hirai, Tetsuya Okayama, Naohisa Yoshida, Kazuhiro Katada, Kazuhiro Kamada, Osamu Handa, Takeshi Ishikawa, Tomohisa Takagi, Hideyuki Konishi, Yoshiaki Kuriu, Masayoshi Nakanishi, Eigo Otsuji, Yoshito Itoh, Yuji Naito
BACKGROUND: Although colorectal cancer (CRC) is one of the most common causes of cancer mortality, early-stage detection improves survival rates dramatically. Because cancer impacts important metabolic pathways, the alteration of metabolite levels as a potential biomarker of early-stage cancer has been the focus of many studies. Here, we used CE-TOFMS, a novel and promising method with small injection volume and high resolution, to separate and detect ionic compounds based on the different migration rates of charged metabolites in order to detect metabolic biomarkers in patients with CRC...
September 20, 2016: Journal of Gastroenterology
Yutaka Konya, Moyu Taniguchi, Eiichiro Fukusaki
Recently, the demand for d-amino acid profiling has been drastically increasing because the significance of d-amino acid in various biological events is suggested. However, the present methodologies for d-amino acid profiling are still unsatisfactory. Therefore, a highly sensitive, robust, high-throughput, and user-friendly method for d-amino acid profiling must be developed. In this paper, we developed a novel method for d-amino acid profiling using a combination of a chiral column and time of flight mass spectrometry (TOFMS)...
September 17, 2016: Journal of Bioscience and Bioengineering
J Budczies
Metabolomics, the newest of the omics sciences that also include genomics, transcriptomics and proteomics, has matured into a reliable high-throughput technology. Gas chromatography combined with time-of-flight mass spectrometry (GC-TOFMS) is a suitable method to analyze the central metabolism in fresh frozen tumor tissue samples. Bioinformatics methods, including the PROFILE clustering developed by us, permit integrated analysis and fast interpretation of metabolomics data in the context of enzymatic reactions and metabolic pathways...
September 15, 2016: Der Pathologe
Yan Wang, Jichun Jiang, Lei Hua, Keyong Hou, Yuanyuan Xie, Ping Chen, Wei Liu, Qingyun Li, Shuang Wang, Haiyang Li
Photon ionization mass spectrometry (PI-MS) is a widely used technique for the online detection of trace substances in complex matrices. In this work, a new high-pressure photon ionization (HPPI) ion source based on a vacuum ultraviolet (VUV) Kr lamp was developed for time-of-flight mass spectrometry (TOFMS). The detection sensitivity was improved by elevating the ion source pressure to about 700 Pa. A radio frequency (RF)-only quadrupole was employed as the ion guide system following the HPPI source to achieve high ion transmission efficiency...
September 20, 2016: Analytical Chemistry
Sabra Botch-Jones, Jamie Foss, David Barajas, Frank Kero, Craig Young, Jason Weisenseel
New psychoactive substances (NPS) have been associated with fatalities and severe injuries in a number of cases in the United States and have led investigators to rethink traditional drug monitoring protocols. Of particular interest are the variable phenethylamine chemical structures known as 'NBOMes', which pose an emerging threat to public health with incidence steadily growing over the past decade. In this study, direct sample analysis (DSA)-time of flight mass spectrometry was employed to leverage rapid and sensitive ambient ionization mass spectrometry without chromatographic separation as verified with an authentic case sample...
October 2016: Forensic Science International
B Apicella, X Li, M Passaro, C Russo
This paper is the second of a series dealing with clusters formation mechanism. In part 1, water clusters with the addition of an electrophilic molecule such as ethanol were studied by Time Of Flight Mass Spectrometry (TOFMS). Mass distributions of molecular clusters of ethanol, water and ethanol-water mixed clusters, were obtained by means of two different ionization methods: Electron Ionization (EI) and picosecond laser Photo-Ionization (PI) at a wavelength of 355 nm. In part 2, the same experimental approach was employed to obtain mass spectra of clusters generated by acetone-water binary mixtures with a different composition...
November 2016: Journal of the American Society for Mass Spectrometry
Elise A Dennis, Alexander W Gundlach-Graham, Steven J Ray, Christie G Enke, Gary M Hieftje
Distance-of-flight mass spectrometry (DOFMS) separates ions of different mass-to-charge (m/z) by the distance they travel in a given time after acceleration. Like time-of-flight mass spectrometry (TOFMS), separation and mass assignment are based on ion velocity. However, DOFMS is not a variant of TOFMS; different methods of ion focusing and detection are used. In DOFMS, ions are driven orthogonally, at the detection time, onto an array of detectors parallel to the flight path. Through the independent detection of each m/z, DOFMS can provide both wider dynamic range and increased throughput for m/z of interest compared with conventional TOFMS...
November 2016: Journal of the American Society for Mass Spectrometry
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
Jumpei Washio, Tamaki Ogawa, Keisuke Suzuki, Yosuke Tsukiboshi, Motohiro Watanabe, Nobuhiro Takahashi
Dental plaque metabolizes both carbohydrates and amino acids. The former can be degraded to acids mainly, while the latter can be degraded to various metabolites, including ammonia, acids and amines, and associated with acid-neutralization, oral malodor and tissue inflammation. However, amino acid metabolism in dental plaque is still unclear. This study aimed to elucidate what kinds of amino acids are available as metabolic substrates and how the amino acids are metabolized in supragingival plaque, by a metabolome analysis...
2016: Biomedical Research
Keyong Hou, Jinxu Li, Tuanshuai Qu, Bin Tang, Liping Zhu, Yunguang Huang, Haiyang Li
RATIONALE: Sulfur hexafluoride (SF6 ) gas-insulated switchgear (GIS) is an essential piece of electrical equipment in a substation, and the concentration of the SF6 decomposition products are directly relevant to the security and reliability of the substation. The detection of SF6 decomposition products can be used to diagnosis the condition of the GIS. METHODS: The decomposition products of SO2 , SO2 F2 , and SOF2 were selected as indicators for the diagnosis. A suitcase time-of-flight mass spectrometer (TOFMS) was designed to perform online GIS failure analysis...
August 2016: Rapid Communications in Mass Spectrometry: RCM
Xiaoji Cao, Chenlu Wang, Weimin Mo
RATIONALE: Aryl thioethers are potentially useful precursors for constructing various biologically active sulfur-containing heterocycles. The detailed relationship between the losses of HS radical and CS with the spin multiplicity of positively charged diphenyl sulfide biradicals derived from 3-iodophenyl phenyl sulfides has not been obtained by tandem mass spectrometry combined with theoretical calculations. METHODS: Collision-induced dissociation mass spectrometry experiments were carried out using an ion trap mass spectrometer with APCI in positive mode...
August 2016: Rapid Communications in Mass Spectrometry: RCM
Saer Samanipour, Katherine Langford, Malcolm J Reid, Kevin V Thomas
Gas chromatography coupled with high resolution time of flight mass spectrometry (GC-HR-TOFMS) has gained popularity for the target and suspect analysis of complex samples. However, confident detection of target/suspect analytes in complex samples, such as produced water, remains a challenging task. Here we report on the development and validation of a two stage algorithm for the confident target and suspect analysis of produced water extracts. We performed both target and suspect analysis for 48 standards, which were a mixture of 28 aliphatic hydrocarbons and 20 alkylated phenols, in 3 produced water extracts...
September 9, 2016: Journal of Chromatography. A
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