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Ambient ionization

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https://www.readbyqxmd.com/read/28099012/aqueous-photochemistry-of-secondary-organic-aerosol-of-%C3%AE-pinene-and-%C3%AE-humulene-oxidized-with-ozone-hydroxyl-radical-and-nitrate-radical
#1
Dian E Romonosky, Ying Li, Manabu Shiraiwa, Alexander Laskin, Julia Laskin, Sergey A Nizkorodov
Formation of secondary organic aerosols (SOA) from biogenic volatile organic compounds (BVOC) occurs via O3- and OH-initiated reactions during the day and reactions with NO3 during the night. We explored the effect of these three oxidation conditions on the molecular composition and aqueous photochemistry of model SOA prepared from two common BVOC. A common monoterpene, α-pinene, and sesquiterpene, α-humulene, were used to form SOA in a smog chamber via BVOC + O3, BVOC + NO3, and BVOC + OH + NOx oxidation...
January 18, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28074623/characterization-and-application-of-a-self-aspirating-electrospray-source-with-pneumatic-assisted-ionization
#2
Quan Yu, Jianchao Zhang, Kai Ni, Xiang Qian, Xiaohao Wang
A single gas-assisted electrospray ion source developed for ambient mass spectrometry is introduced in this paper. Simultaneous self-aspiration and electrospray could be achieved by using a constant sheath gas flow supplied from a mini air pump. A gas dynamic study of the spray module is carried out for structural optimization. The entire device exhibits a simplified design and has been systematically characterized through both simulated and experimental investigations. According to the results, the ion source exhibited satisfactory stability and the ability for quantitative operation in routine electrospray ionization mass spectrometry...
January 11, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28068517/rapid-analysis-of-drug-dissolution-by-paper-spray-ionization-mass-spectrometry
#3
Yang Liu, Ning Liu, Ya-Nan Zhou, Lan Lin, Lan He
With a great quantity of solid dosage tested by dissolution technology, developing a rapid and sensitive method to access the content of drug within dissolution media is highly desired by analysts and scientists. Traditionally, dissolution media is not compatible with mass spectrometry since the inorganic salts in the media might damage the mass spectrometer. Here, paper spray ionization mass spectrometry (PSI-MS), one of the ambient mass spectrometry technologies, is developed to characterize the content of drugs in dissolution media...
December 23, 2016: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28050872/characterization-of-polyolefin-pyrolysis-species-produced-under-ambient-conditions-by-fourier-transform-ion-cyclotron-resonance-mass-spectrometry-and-ion-mobility-mass-spectrometry
#4
Mathilde Farenc, Matthias Witt, Kirsten Craven, Caroline Barrère-Mangote, Carlos Afonso, Pierre Giusti
Polyolefins such as polyethylene (PE) and polypropylene (PP) are often characterized from their pyrolysis products by Py-MS. Nowadays the development of plasma-based direct probe atmospheric pressure sources allow the direct analysis of these polymers. These sources operate at atmospheric pressure, which implies a limited control of the ionization conditions. It was shown that side reactions could occur with species present in air, such as O2, which may lead to the formation of oxidized compounds. In this work, ion mobility-mass spectrometry (IM-MS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR) were used for the exhaustive characterization of the PP and PE pyrolysis ions produced using plasma-based atmospheric pressure ion sources...
January 3, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28045006/electrochemical-direct-writing-and-erasing-of-silver-nanostructures-on-phosphate-glass-using-atomic-force-microscopy
#5
Shama F Barna, Kyle E Jacobs, Glennys A Mensing, Placid M Ferreira
This paper reports a liquid-free, mask-less electrochemical direct-write lithographic technique using an atomic force microscopy (AFM) probe for writing silver nanostructures in minutes on an optically transparent substrate. Under ambient conditions, silver is locally and controllably extracted to the surface of superionic (AgI)0.25 (AgPO3)0.75 glass by bringing a conductive AFM probe tip in contact with it, biasing the probe with a negative voltage, and regulating the resulting current. The growth mechanism of the resulting nanostructure is explored by extracting silver with a stationary AFM tip on the surface of the silver...
January 3, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28042191/ambient-ionization-and-miniature-mass-spectrometry-system-for-chemical-and-biological-analysis
#6
Xiaoxiao Ma, Zheng Ouyang
Ambien ionization and miniaturization of mass spectrometers are two fields in mass spectrometry that have advanced significantly in the last decade. The integration of the techniques developed in these two fields is leading to the development of complete miniature analytical systems that can be used for on-site or point-of-care analysis by non-expert users. In this review, we report the current status of development in ambient ionization and miniature mass spectrometers, with an emphasis on those techniques with potential impact on the point-of-care (POC) diagnostics...
December 2016: Trends in Analytical Chemistry: TRAC
https://www.readbyqxmd.com/read/28035803/molecularly-imprinted-membrane-electrospray-ionization-for-direct-sample-analyses
#7
Tianyi Li, Liusheng Fan, Yingfeng Wang, Xuebin Huang, Jianguo Xu, Jinxing Lu, Mei Zhang, Wei Xu
Typically dealing with practical samples with very complex matrices, ambient ionization mass spectrometry suffers from low detection sensitivity. In this study, molecular imprinting technology was explored and integrated with membrane electrospray ionization (MESI) method for direct sample analyses. By enriching targeted analytes on molecularly imprinted membrane (MIM), 10- to 50-fold limit of quantitation improvement could be achieved compared to conventional nano-electrospray ionization method or other ambient ionization method...
December 28, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28010838/microplasma-based-flowing-atmospheric-pressure-afterglow-fapa-source-for-ambient-desorption-ionization-mass-spectrometry
#8
Offer M Zeiri, Andrew P Storey, Steven J Ray, Gary M Hieftje
A new direct-current microplasma-based flowing atmospheric pressure afterglow (FAPA) source was developed for use in ambient desorption-ionization mass spectrometry. The annular-shaped microplasma is formed in helium between two concentric stainless-steel capillaries that are separated by an alumina tube. Current-voltage characterization of the source shows that this version of the FAPA operates in the normal glow-discharge regime. A glass surface placed in the path of the helium afterglow reaches temperatures of up to approximately 400 °C; the temperature varies with distance from the source and helium flow rate through the source...
February 1, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28004779/estimation-of-the-toxicity-of-sulfadiazine-to-daphnia-magna-using-negligible-depletion-hollow-fiber-liquid-phase-microextraction-independent-of-ambient-ph
#9
Kailin Liu, Shiji Xu, Minghuan Zhang, Yahong Kou, Xiaomao Zhou, Kun Luo, Lifeng Hu, Xiangying Liu, Min Liu, Lianyang Bai
The toxicity of ionizable organic compounds to organisms depends on the pH, which therefore affects risk assessments of these compounds. However, there is not a direct chemical method to predict the toxicity of ionizable organic compounds. To determine whether hollow-fiber liquid-phase microextraction (HF-LPME) is applicable for this purpose, a three-phase HF-LPME was used to measure sulfadiazine and estimate its toxicity to Daphnia magna in solutions of different pH. The result indicated that the sulfadiazine concentrations measured by HF-LPME decreased with increasing pH, which is consistent with the decreased toxicity...
December 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/28000107/analytical-validation-of-a-portable-mass-spectrometer-featuring-interchangeable-ambient-ionization-sources-for-high-throughput-forensic-evidence-screening
#10
Zachary E Lawton, Angelica Traub, William L Fatigante, Jose Mancias, Adam E O'Leary, Seth E Hall, Jamie R Wieland, Herbert Oberacher, Michael C Gizzi, Christopher C Mulligan
Forensic evidentiary backlogs are indicative of the growing need for cost-effective, high-throughput instrumental methods. One such emerging technology that shows high promise in meeting this demand while also allowing on-site forensic investigation is portable mass spectrometric (MS) instrumentation, particularly that which enables the coupling to ambient ionization techniques. While the benefits of rapid, on-site screening of contraband can be anticipated, the inherent legal implications of field-collected data necessitates that the analytical performance of technology employed be commensurate with accepted techniques...
December 20, 2016: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/27998483/dielectric-barrier-discharges-applied-for-soft-ionization-and-their-mechanism
#11
REVIEW
Sebastian Brandt, Felix David Klute, Alexander Schütz, Joachim Franzke
Dielectric barrier discharges are used for analytical applications as dissociative source for optical emission spectrometry and for ambient-ionization techniques. In the range of ambient-ionization techniques it has attracted much attention in fields like food safety, biological analysis, mass spectrometry for reaction monitoring and imaging forensic identification. In this review some examples are given for the application as desorption/ionization source as well as for the sole application as ionization source with different sample introductions...
January 25, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27989134/stability-and-application-of-reactive-nitrogen-and-oxygen-species-induced-hemoglobin-modifications-in-dry-blood-spots-as-analyzed-by-liquid-chromatography-tandem-mass-spectrometry
#12
Hauh-Jyun Candy Chen, Chih-Huang Fan, Ya-Fen Yang
Dried blood spot (DBS) is an emerging microsampling technique for the bioanalysis of small molecules, including fatty acids, metabolites, drugs, and toxicants. DBS offers many advantages as a sample format including easy sample collection and cheap sample shipment. Hemoglobin adducts have been recognized as a suitable biomarker for monitoring chemical exposure. We previously reported that certain modified peptides in hemoglobin derived from reactive chlorine, nitrogen, and oxygen species are associated with factors including smoking, diabetes mellitus, and aging...
December 19, 2016: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/27922018/non-thermal-hydrogen-atoms-in-the-terrestrial-upper-thermosphere
#13
Jianqi Qin, Lara Waldrop
Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen atoms in the upper thermosphere. Analysis of satellite measurements indicates that the upper thermospheric hydrogen temperature, more precisely the mean kinetic energy of the atomic hydrogen population, increases significantly with declining solar activity, contrary to contemporary understanding of thermospheric behaviour...
December 6, 2016: Nature Communications
https://www.readbyqxmd.com/read/27916116/atmospheric-pressure-solution-cathode-glow-discharge-a-versatile-ion-source-for-atomic-and-molecular-mass-spectrometry
#14
Andrew J Schwartz, Kelsey L Williams, Gary M Hieftje, Jacob T Shelley
An atmospheric-pressure solution-cathode glow discharge (SCGD) has been evaluated as an ion source for atomic, molecular, and ambient desorption/ionization mass spectrometry. The SCGD consists of a direct-current plasma, supported in the ambient air in the absence of gas flows, and sustained upon the surface of a flowing liquid cathode. Analytes introduced in the flowing liquid, as an ambient gas, or as a solid held near the plasma are vaporized and ionized by interactions within or near the discharge. Introduction of acidic solutions containing metal salts produced bare elemental ions as well as H2O, OH(-) and NO3(-) adducts...
January 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/27908190/accuracy-reproducibility-and-uncertainty-analysis-of-thyroid-probe-based-activity-measurements-for-determination-of-dose-calibrator-settings
#15
Pedro L Esquinas, Jesse Tanguay, Marjorie Gonzalez, Milan Vuckovic, Cristina Rodríguez-Rodríguez, Urs O Häfeli, Anna Celler
PURPOSE: In the nuclear medicine department, the activity of radiopharmaceuticals is measured using dose calibrators (DCs) prior to patient injection. The DC consists of an ionization chamber that measures current generated by ionizing radiation (emitted from the radiotracer). In order to obtain an activity reading, the current is converted into units of activity by applying an appropriate calibration factor (also referred to as DC dial setting). Accurate determination of DC dial settings is crucial to ensure that patients receive the appropriate dose in diagnostic scans or radionuclide therapies...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27896697/metal-cationization-extractive-electrospray-ionization-mass-spectrometry-of-compounds-containing-multiple-oxygens
#16
Kenneth D Swanson, Sandra E Spencer, Gary L Glish
Extractive electrospray ionization is an ambient ionization technique that allows real-time sampling of liquid samples, including organic aerosols. Similar to electrospray ionization, the composition of the electrospray solvent used in extractive electrospray ionization can easily be altered to form metal cationized molecules during ionization simply by adding a metal salt to the electrospray solvent. An increase in sensitivity is observed for some molecules that are lithium, sodium, or silver cationized compared with the protonated molecule formed in extractive electrospray ionization with an acid additive...
November 28, 2016: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/27873315/incorporation-of-conjugated-fatty-acids-into-nile-tilapia-oreochromis-niloticus
#17
Elton G Bonafé, Luana C de Figueiredo, Alessandro F Martins, Johny P Monteiro, Oscar O S Junior, Edmilson A Canesin, Swami Arêa Maruyama, Jesuí V Visentainer
The aim of this work was to improve the nutritional quality of Nile tilapia meat through enriched diets with conjugated isomers of linolenic acid from tung oil. The transfer process of conjugated fatty acids (CFA) into fish muscle tissue was evaluated by gas chromatography-flame ionization detection (GC-FID) and Easy Ambient Sonic-Spray Ionization Mass Spectrometry (EASI-MS). The results showed that conjugated fatty acids were transferred from enriched diet for muscle tissue of Nile tilapia. Conjugated linoleic acids biosynthesis from conjugated linolenic acids was also observed after ten days...
November 21, 2016: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/27865893/sex-and-genetic-differences-in-the-effects-of-acute-diesel-exhaust-exposure-on-inflammation-and-oxidative-stress-in-mouse-brain
#18
Toby B Cole, Jacki Coburn, Khoi Dao, Pam Roqué, Yu-Chi Chang, Vrinda Kalia, Tomas R Guilarte, Jennifer Dziedzic, Lucio G Costa
In addition to increased morbidity and mortality caused by respiratory and cardiovascular diseases, air pollution may also contribute to central nervous system (CNS) diseases. Traffic-related air pollution is a major contributor to global air pollution, and diesel exhaust (DE) is its most important component. DE contains more than 40 toxic air pollutants and is a major constituent of ambient particulate matter (PM), particularly of ultrafine-PM. Limited information suggests that exposure to DE may cause oxidative stress and neuroinflammation in the CNS...
December 30, 2016: Toxicology
https://www.readbyqxmd.com/read/27830711/structure-conserving-spontaneous-transformations-between-nanoparticles
#19
K R Krishnadas, Ananya Baksi, Atanu Ghosh, Ganapati Natarajan, Thalappil Pradeep
Ambient, structure- and topology-preserving chemical reactions between two archetypal nanoparticles, Ag25(SR)18 and Au25(SR)18, are presented. Despite their geometric robustness and electronic stability, reactions between them in solution produce alloys, AgmAun(SR)18 (m+n=25), keeping their M25(SR)18 composition, structure and topology intact. We demonstrate that a mixture of Ag25(SR)18 and Au25(SR)18 can be transformed to any arbitrary alloy composition, AgmAun(SR)18 (n=1-24), merely by controlling the reactant compositions...
November 10, 2016: Nature Communications
https://www.readbyqxmd.com/read/27822645/comparison-of-paper-spray-mass-spectrometry-analysis-of-dried-blood-spots-from-devices-used-for-in-field-collection-of-clinical-samples
#20
Karen E Yannell, Kristina R Kesely, Huynh Dinh Chien, Candice B Kissinger, R Graham Cooks
Paper spray (PS) is an ambient ionization technique applicable to ionizing analytes from untreated dried biofluid samples. In-field sample analysis could benefit from the capability to use a finger prick of blood to measure drugs in whole blood at low cost and in a short time. Some studies may require specialized blood collection devices that can be used in remote areas. In this study, four different dried blood spot (DBS) devices are used with PS sources and tested for rapid quantification of imatinib and N-desmethyl-imatinib...
January 2017: Analytical and Bioanalytical Chemistry
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