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Ambient ionization

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https://www.readbyqxmd.com/read/28535590/emission-of-volatile-organic-compounds-and-production-of-secondary-organic-aerosol-from-stir-frying-spices
#1
Tengyu Liu, Qianyun Liu, Zijun Li, Lei Huo, ManNin Chan, Xue Li, Zhen Zhou, Chak K Chan
Cooking is an important source of volatile organic compounds (VOCs) and a potential source of secondary organic aerosol (SOA) both indoors and outdoors. In this study, VOC emissions from heating corn oil and stir-frying spices (i.e. garlic, ginger, myrcia and zanthoxylum piperitum (Sichuan pepper)) were characterized using an on-line membrane inlet vacuum ultraviolet single-photon ionization time-of-flight mass spectrometer (VUV-SPI-TOFMS). VOC emissions from heating corn oil were dominated by aldehydes, which were enhanced by factors of one order of magnitude when stir-frying spices...
May 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28530092/fibroblast-cytophilic-and-hela-cytotoxic-dual-function-carbon-nanoribbon-network-platform
#2
A K M Rezaul Haque Chowdhury, Bo Tan, Krishnan Venkatakrishnan
Carbon nanomaterials have emerged as a promising material in cancer diagnosis and therapy. Carbon nanomaterials/nanostructures (C-C molecular structure) act as a carrier/skeleton and require further surface modification through functionalization with chemicals or biomolecules to attain a cell response. We report the synthesis of a novel carbon nanoribbon network (CNRN) platform that possesses a combination of C-C and C-O bond architecture. The bioactive CNRN showed enhanced ability for cell adhesion. Most importantly, it induced opposite cell responses from healthy cells and cancerous cells, cytophilic to fibroblasts but cytotoxic to HeLa cells...
May 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28517936/in-situ-hydrogel-conditioning-of-tissue-samples-to-enhance-the-drug-s-sensitivity-in-ambient-mass-spectrometry-imaging
#3
Xiaowei Song, Zhigang Luo, Xin Li, Tiegang Li, Zhonghua Wang, Chenglong Sun, Luojiao Huang, Ping Xie, Xiaoyu Liu, Jiuming He, Zeper Abliz
Ion suppression from the tissue matrix has a severe effect on the mass spectrometry imaging (MSI) of drugs. This problem hinders further applications of MSI in preclinical drug research and development. In this study, an in situ hydrogel conditioning method was developed to enhance the sensitivity of air-flow-assisted desorption electrospray ionization (AFADESI)-MSI. Instead of the traditional wash-up or digestion treatment in solvent, this method used a solid phase hydrogel to "wash" tissue sections. It was demonstrated that this in situ hydrogel conditioning method improve the drug signal by as much as 2- to 25-folds in MSI, especially for hydrophobic compounds...
May 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28502428/non-proximate-mass-spectrometry-using-a-heated-1-m-long-ptfe-tube-and-an-air-tight-apci-ion-source
#4
Dilshadbek T Usmanov, Kenzo Hiraoka, Hiroshi Wada, Masaya Matsumura, Sachiyo Sanada-Morimura, Hiroshi Nonami, Shinichi Yamabe
Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device...
June 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28462580/ionic-and-neutral-mechanisms-for-c-h-bond-silylation-of-aromatic-heterocycles-catalyzed-by-potassium-tert-butoxide
#5
Shibdas Banerjee, Yun-Fang Yang, Ian D Jenkins, Yong Liang, Anton A Toutov, Wen-Bo Liu, David P Schuman, Robert H Grubbs, Brian M Stoltz, Elizabeth H Krenske, Kendall N Houk, Richard N Zare
Exploiting C-H bond activation is difficult, although some success has been achieved using precious metal catalysts. Recently, it was reported that C-H bonds in aromatic heterocycles were converted to C-Si bonds by reaction with hydrosilanes under the catalytic action of potassium tert-butoxide alone. The use of Earth-abundant potassium cation as a catalyst for C-H bond functionalization seems to be without precedent, and no mechanism for the process was established. Using ambient ionization mass spectrometry, we are able to identify crucial ionic intermediates present during the C-H silylation reaction...
May 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28460870/a-high-throughput-mass-spectrometry-screening-analysis-based-on-two-dimensional-carbon-microfiber-fractionation-system
#6
Biao Ma, Yilin Zou, Xuan Xie, Jinhua Zhao, Xiangfan Piao, Jingyi Piao, Zhongping Yao, Maurizio Quinto, Gang Wang, Donghao Li
A novel high-throughput, solvent saving and versatile integrated two-dimensional microscale carbon fiber/active carbon fiber system (2DμCFs) that allows a simply and rapid separation of compounds in low-polar, medium-polar and high-polar fractions, has been coupled with ambient ionization-mass spectrometry (ESI-Q-TOF-MS and ESI-QqQ-MS) for screening and quantitative analyses of real samples. 2DμCFs led to a substantial interference reduction and minimization of ionization suppression effects, thus increasing the sensitivity and the screening capabilities of the subsequent MS analysis...
April 25, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28455844/open-probe-fast-gc-ms-combining-ambient-sampling-ultra-fast-separation-and-in-vacuum-ionization-for-real-time-analysis
#7
Uri Keshet, Tal Alon, Alexander B Fialkov, Aviv Amirav
An Open Probe inlet was combined with a low thermal mass ultra-fast gas chromatograph (GC), in-vacuum electron eonization (EI) ion source and a mass spectrometer (MS) of GC-MS for obtaining real time analysis with separation. The Open Probe enables ambient sampling via sample vaporization in an oven that is open to room air and the ultra-fast GC provides ~30 s separation while if no separation is required it can act as a transfer line with 2-3 s sample transfer time. Sample analysis is as simple as touching the sample, pushing the sample holder into the open probe oven and getting the results in 30 s...
April 28, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28451286/postsynthetic-ionization-of-an-imidazole-containing-metal-organic-framework-for-the-cycloaddition-of-carbon-dioxide-and-epoxides
#8
Jun Liang, Rui-Ping Chen, Xiu-Yun Wang, Tao-Tao Liu, Xu-Sheng Wang, Yuan-Biao Huang, Rong Cao
A bifunctional imidazolium functionalized zirconium metal-organic framework (Zr-MOF), (I(-))Meim-UiO-66 (2), was successfully prepared from the imidazole-containing Zr-MOF Im-UiO-66 (1) by a post-synthetic modification (PSM) method. It was found that the crystal size and pore features of the imidazole-containing 1 could be tuned at the nanoscale. The bifunctional MOF 2, containing Brønsted acid sites and iodide ions, was shown to be an efficient and recyclable heterogeneous catalyst for the cycloaddition of carbon dioxide (CO2) with epoxides, without the use of any co-catalyst, at ambient pressure...
February 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28443843/atmospheric-pressure-soft-ionization-for-gas-chromatography-with-dielectric-barrier-discharge-ionization-mass-spectrometry-gc-dbdi-ms
#9
Mario F Mirabelli, Jan-Christoph Wolf, Renato Zenobi
In this study, a gas chromatography (GC) system was interfaced to a high-resolution Orbitrap mass spectrometer by means of an active capillary plasma ionization source, based on dielectric barrier discharge ionization (DBDI). This allowed highly efficient soft ionization of gas-phase, chromatographically resolved compounds at ambient pressure. Several pesticides and illicit drugs were analyzed, and the limits of detections (LODs) were as low as 30 pg mL(-1) for the GC-DBDI-MS coupling (corresponding to 60 fg on-column sensitivity) and 30 fg mL(-1) for SPME-GC-DBDI-MS...
April 26, 2017: Analyst
https://www.readbyqxmd.com/read/28443842/pulsed-valve-matrix-assisted-ionization
#10
Bijay Banstola, Kermit K Murray
We have developed a new ionization approach for matrix-assisted ionization with high temporal resolution using an electrically actuated pulsed valve. Matrix and analyte samples are deposited on a thin metal foil and placed at the inlet of an ambient ionization mass spectrometer. When the pulsed valve is actuated, a short puff of high pressure gas impinges on the foil and ejects particulate from the sample on the opposite side. Highly charged ions are formed from the particles at the mass spectrometer inlet...
April 26, 2017: Analyst
https://www.readbyqxmd.com/read/28420232/gas-phase-carboxylic-acids-in-a-university-classroom-abundance-variability-and-sources
#11
Shang Liu, Samantha L Thompson, Harald Stark, Paul J Ziemann, Jose L Jimenez
Gas-phase carboxylic acids are ubiquitous in ambient air, yet their indoor occurrence and abundance are poorly characterized. To fill this gap, we measured gas-phase carboxylic acids in real-time inside and outside of a university classroom using a high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) equipped with an acetate ion source. A wide variety of carboxylic acids were identified indoors and outdoors, including monoacids, diacids, hydroxy acids, carbonyl acids, and aromatic acids...
May 2, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28416487/metabolic-markers-and-statistical-prediction-of-serous-ovarian-cancer-aggressiveness-by-ambient-ionization-mass-spectrometry-imaging
#12
Marta Sans, Kshipra M Gharpure, Robert Tibshirani, Jialing Zhang, Li Liang, Jinsong Liu, Jonathan H Young, Robert Dood, Anil K Sood, Livia Eberlin
Ovarian high-grade serous carcinoma (HGSC) results in the highest mortality among gynecological cancers, developing rapidly and aggressively. Dissimilarly, serous borderline ovarian tumors (BOT) can progress into low-grade serous carcinomas and have relatively indolent clinical behavior. The underlying biological differences between HGSC and BOT call for accurate diagnostic methodologies and tailored treatment options, and identification of molecular markers of aggressiveness could provide valuable biochemical insights and improve disease management...
April 17, 2017: Cancer Research
https://www.readbyqxmd.com/read/28401996/exploration-and-performance-evaluation-of-microwave-induced-plasma-with-different-discharge-gases-for-ambient-desorption-ionization-mass-spectrometry
#13
Jingwei Yin, Zhongjun Zhao, Xuefang Zhan, Yixiang Duan
RATIONALE: Microwave-induced plasma (MIP) with different discharge gases of argon or helium provides significant plasma-based ambient desorption/ionization sources, which have potential applicability in direct analysis of complex samples without any sample pre-treatment. In this study, experiments were conducted to better understand microwave-induced plasma desorption/ionization (MIPDI) sources and the corresponding ionization mechanisms. METHODS: Emission spectra of microwave-induced argon (MIP-Ar) and helium (MIP-He) plasmas were obtained from the plasma tail flame of a MIP source...
April 12, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28395774/determination-of-elemental-composition-of-metals-using-ambient-organic-mass-spectrometry
#14
Christopher Shiea, Yeou-Lih Huang, Sy-Chyi Cheng, Yi-Lun Chen, Jentaie Shiea
Conventional inorganic mass spectrometric (MS) analysis of metals can require time-consuming and tedious sample preparation. We thus report the novel and direct characterization of metals in solid samples using an organic MS technique known as electrospray laser desorption ionization mass spectrometry (ELDI/MS). No sample pretreatment was needed, and results were rapidly obtained due to the ambient and laser-based nature of ELDI/MS. Metals from samples were desorbed and ionized by laser irradiation, after which they reacted with EDTA and then post-ionized and detected as metal-EDTA complexes...
May 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28394446/laser-ablation-electrospray-ionization-mass-spectrometry-with-ion-mobility-separation-reveals-metabolites-in-the-symbiotic-interactions-of-soybean-roots-and-rhizobia
#15
Sylwia A Stopka, Beverly J Agtuca, David W Koppenaal, Ljiljana Paša-Tolić, Gary Stacey, Akos Vertes, Christopher R Anderton
Technologies enabling in situ metabolic profiling of living plant systems are invaluable for understanding physiological processes and could be used for rapid phenotypic screening (e.g., to produce plants with superior biological nitrogen fixing ability). The symbiotic interaction between legumes and nitrogen-fixing soil bacteria results in a specialized plant organ (i.e., root nodule) where the exchange of nutrients between host and endosymbiont occurs. Laser ablation electrospray ionization mass spectrometry (LAESI-MS) is a method that can be performed under ambient conditions requiring minimal sample preparation...
April 10, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28392779/complementary-metaproteomic-approaches-to-assess-the-bacterioplankton-response-toward-a-phytoplankton-spring-bloom-in-the-southern-north-sea
#16
Lars Wöhlbrand, Bernd Wemheuer, Christoph Feenders, Hanna S Ruppersberg, Christina Hinrichs, Bernd Blasius, Rolf Daniel, Ralf Rabus
Annually recurring phytoplankton spring blooms are characteristic of temperate coastal shelf seas. During these blooms, environmental conditions, including nutrient availability, differ considerably from non-bloom conditions, affecting the entire ecosystem including the bacterioplankton. Accordingly, the emerging ecological niches during bloom transition are occupied by different bacterial populations, with Roseobacter RCA cluster and SAR92 clade members exhibiting high metabolic activity during bloom events...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28364225/comparison-of-ambient-and-atmospheric-pressure-ion-sources-for-cystic-fibrosis-exhaled-breath-condensate-ion-mobility-mass-spectrometry-metabolomics
#17
Xiaoling Zang, José J Pérez, Christina M Jones, María Eugenia Monge, Nael A McCarty, Arlene A Stecenko, Facundo M Fernández
Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The vast majority of the mortality is due to progressive lung disease. Targeted and untargeted CF breath metabolomics investigations via exhaled breath condensate (EBC) analyses have the potential to expose metabolic alterations associated with CF pathology and aid in assessing the effectiveness of CF therapies. Here, transmission-mode direct analysis in real time traveling wave ion mobility spectrometry time-of-flight mass spectrometry (TM-DART-TWIMS-TOF MS) was tested as a high-throughput alternative to conventional direct infusion (DI) electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) methods, and a critical comparison of the three ionization methods was conducted...
March 31, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28351629/detection-of-sub-pptv-benzene-toluene-and-ethylbenzene-via-low-pressure-photoionization-mass-spectrometry
#18
Zhen Li, Ce Xu, Jinian Shu
This paper reports on the advanced development of an ultrasensitive method for the detection of benzene, toluene, and ethylbenzene (or BTE) by low-pressure photoionization mass spectrometry (LPPI-MS). The LPPI source is composed of a laboratory-assembled krypton lamp and a stainless steel cylindrical ionizer. A compact V-shaped mass spectrometer is coupled to the LPPI source with a set of ion immigration optics under dc bias. The fixed standard concentration (FSC) and fixed standard volume (FSV) method are employed to calibrate the sensitivities of the instrument...
April 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28340788/rapid-identification-and-desorption-mechanisms-of-nitrogen-based-explosives-by-ambient-micro-fabricated-glow-discharge-plasma-desorption-ionization-mfgdp-mass-spectrometry
#19
CaiYan Tian, JinWei Yin, ZhongJun Zhao, Yinchenxi Zhang, YiXiang Duan
A novel technique of micro-fabricated glow discharge plasma desorption/ionization mass spectrometry was investigated for the first time in negative ion mode in this study. Negative ion micro-fabricated glow discharge plasma desorption/ionization mass spectrometry (NI-MFGDP-MS) was successfully applied to identify trace explosives in open air. Six explosives and explosives-related compounds were directly analyzed in seconds with this ion source. The ions of [M-H](-) were predominant for 2-methyl-1,3,5-trinitrobenzene (trinitrotoluene, TNT) and 2,4,6-trinitrophenol (picric acid), and [M+NO3](-) were dominant ions for 1,3,5-trinitro-perhydro-1,3,5-triazine (cyclonite, RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (octogen, HMX), 1,2,3-trinitroxypropane (nitroglycerin, NG), and pentaerythritol tetranitrate (PETN)...
May 15, 2017: Talanta
https://www.readbyqxmd.com/read/28337399/clinical-application-of-ambient-ionization-mass-spectrometry
#20
Li-Hua Li, Hua-Yi Hsieh, Cheng-Chih Hsu
Ambient ionization allows mass spectrometry analysis directly on the sample surface under atmospheric pressure with almost zero sample pretreatment. Since the development of desorption electrospray ionization (DESI) in 2004, many other ambient ionization techniques were developed. Due to their simplicity and low operation cost, rapid and on-site clinical mass spectrometry analysis becomes real. In this review, we will highlight some of the most widely used ambient ionization mass spectrometry approaches and their applications in clinical study...
2017: Mass Spectrometry
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