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Ambient ionization

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https://www.readbyqxmd.com/read/28640577/laser-ablation-molecular-isotopic-spectrometry-for-molecules-formation-chemistry-in-fs-laser-ablated-plasmas
#1
Huaming Hou, Xianglei Mao, Vassilia Zorba, Richard E Russo
Recently, laser ablated molecular isotopic spectrometry (LAMIS) has expanded its capability to explore molecules formation mechanism in laser induced plasma in addition to isotope analysis. LAMIS is powerful tool for tracking the origination of atoms that involved in formation of investigated molecules by labeling atoms with its isotopic substitution. The evolutionary formation pathways of organic molecules, especially of C2 dimers and CN radicals, were frequently reported. However, very little is known about the formation pathways for metallic radicals and heterodimers in laser ablated plasma...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28636372/surface-desorption-dielectric-barrier-discharge-ionization-mass-spectrometry
#2
Hong Zhang, Jie Jiang, Na Li, Ming Li, Yingying Wang, Jing He, Hong You
A variant of dielectric-barrier discharge named surface desorption dielectric-barrier discharge ionization (SDDBDI) mass spectrometry was developed for high-efficiency ion transmission and high spatial resolution imaging. In SDDBDI, a tungsten nanotip and the inlet of the mass spectrometer are used as electrodes, and a piece of cover slip is used as a sample plate as well as an insulating dielectric barrier, which simplifies the configuration of instrument and thus the operation. Different from volume dielectric-barrier discharge (VDBD), the microdischarges are generated on the surface at SDDBDI, and therefore the plasma density is extremely high...
June 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28632988/solid-sampling-with-a-diode-laser-for-portable-ambient-mass-spectrometry
#3
Yeni P Yung, Raveendra Wickramasinghe, Anu Vaikkinen, Tiina Johanna Kauppila, Igor V Veryovkin, Luke Hanley
A handheld diode laser is implemented for solid sampling in portable ambient mass spectrometry (MS). Specifically, a pseudo-continuous wave battery-powered surgical laser diode is employed for portable laser diode thermal desorption (LDTD) at 940 nm and compared with nanosecond pulsed laser ablation at 2940 nm. Postionization is achieved in both cases using atmospheric pressure photoionization (APPI). The laser ablation atmospheric pressure photoionization (LAAPPI) and LDTD-APPI mass spectra of sage leaves (Salvia officinalis) using a field-deployable quadrupole ion trap MS display many similar ion peaks, as do the mass spectra of membrane grown biofilms of Pseudomonas aeruginosa...
June 20, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28631113/fast-determination-of-ingredients-in-solid-pharmaceuticals-by-microwave-enhanced-in-source-decay-of-microwave-plasma-torch-mass-spectrometry
#4
Rui Su, Xinchen Wang, Changming Hou, Meiling Yang, Keke Huang, Huanwen Chen
Rapid qualitative and quantitative analysis of solid samples (e.g., pharmaceutical preparations) by using a small and low-resolution mass spectrometer without MS/MS function is still a challenge in ambient pressure ionization mass spectrometric analysis. Herein, a practically efficient method termed microwave-enhanced in-source decay (MEISD) using microwave plasma torch desorption ionization coupled with time-of-flight mass spectrometry (MPTDI-TOF MS) was developed for fast analysis of pharmaceutical tablets using a miniature TOF mass spectrometer without tandem mass function...
June 19, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28628730/comparative-study-on-ambient-ionization-methods-for-direct-analysis-of-navel-orange-tissues-by-mass-spectrometry
#5
H Zhang, A Bibi, H Lu, J Han, H Chen
It is of sustainable interest to improve the sensitivity and selectivity of the ionization process, especially for direct analysis of complex samples without matrix separation. Herein, four ambient ionization methods including desorption atmospheric pressure chemical ionization (DAPCI), heat-assisted desorption atmospheric pressure chemical ionization (heat-assisted DAPCI), microwave plasma torch (MPT), and internal extractive electrospray ionization (iEESI) were employed for comparative analysis of the navel orange tissue samples by mass spectrometry...
June 19, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28627748/on-line-reaction-monitoring-by-mass-spectrometry-modern-approaches-for-the-analysis-of-chemical-reactions
#6
REVIEW
Andrew Ray, Tony Bristow, Chris Whitmore, Jackie Mosely
The application of on-line mass spectrometry for direct analysis of chemical and other types of process continues to grow in importance and impact. The ability of the technique to characterize many aspects of a chemical reaction such as product and impurity formation, along with reactant consumption in a single experiment is key to its adoption and development. Innovations in ionization techniques and mass spectrometry instrumentation are enabling this adoption. An increasing range of ambient ionization techniques make on-line mass spectrometry applicable to a large range of chemistries...
June 19, 2017: Mass Spectrometry Reviews
https://www.readbyqxmd.com/read/28625676/comprehensive-determination-of-macrolide-antibiotics-their-synthesis-intermediates-and-transformation-products-in-wastewater-effluents-and-ambient-waters-by-liquid-chromatography-tandem-mass-spectrometry
#7
Ivan Senta, Ivona Krizman-Matasic, Senka Terzic, Marijan Ahel
Macrolide antibiotics are a prominent group of emerging contaminants frequently found in wastewater effluents and wastewater-impacted aquatic environments. In this work, a novel analytical method for simultaneous determination of parent macrolide antibiotics (azithromycin, erythromycin, clarithromycin and roxithromycin), along with their synthesis intermediates, byproducts, metabolites and transformation products in wastewater and surface water was developed and validated. Samples were enriched using solid-phase extraction on Oasis HLB cartridges and analyzed by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry...
June 3, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28613832/monitoring-the-on-surface-synthesis-of-graphene-nanoribbons-by-mass-spectrometry
#8
Wen Zhang, Zongping Chen, Bo Yang, Xiao-Ye Wang, Reinhard Berger, Akimitsu Narita, Gabriela Borin Barin, Pascal Ruffieux, Roman Fasel, Xinliang Feng, Hans Joachim Räder, Klaus Müllen
We present a mass spectrometric approach to monitor and characterize the intermediates of graphene nanoribbon (GNR) formation by chemical vapor deposition (CVD) on top of Au(111) surfaces. Information regarding the repeating units, lengths, and termini can be obtained directly from the surface sample by a modified matrix assisted laser desorption/ionization (MALDI) method. The mass spectrometric results reveal ample oxidative side reactions under CVD conditions which can, however, be diminished drastically by introduction of protective H2 gas at ambient pressure...
June 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28605022/forensic-analysis-of-stains-on-fabric-using-direct-analysis-in-real-time-ionization-with-high-resolution-accurate-mass-mass-spectrometry
#9
Sara E Kern, John B Crowe, Jonathan J Litzau, Douglas T Heitkemper
A rapid technique using direct analysis in real-time (DART) ambient ionization coupled to a high-resolution accurate mass-mass spectrometer (HRAM-MS) was employed to analyze stains on an individual's pants suspected to have been involved in a violent crime. The victim was consuming chocolate ice cream at the time of the attack, and investigators recovered the suspect's pants exhibiting splatter stains. Liquid chromatography with mass spectral detection (LC-MS) and stereoscopic light microscopy (SLM) were also utilized in this analysis...
June 12, 2017: Journal of Forensic Sciences
https://www.readbyqxmd.com/read/28601765/application-of-volumetric-absorptive-microsampling-device-for-quantification-of-tacrolimus-in-human-blood-as-a-model-drug-of-high-blood-cell-partition
#10
Kenji Kita, Yuji Mano
Volumetric absorptive microsampling device (VAMS) was evaluated for bioanalysis of tacrolimus, which was used as a model drug with high blood cell partition. Aliquots of blood (ca. 10μL) with different hematocrits and fortified with tacrolimus were wicked up by VAMS and tacrolimus was extracted with a methanol-water mixture (1:1, v/v) via sonication. After chromatography on an AQUITY UPLC HSS T3 column (100×2.1 i.d., mm, 1.8μm), tacrolimus and the internal standard ascomycin, were detected in the positive ion mode with electrospray ionization by monitoring of transitions m/z 826...
June 3, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28581554/-ag59-2-5-dcbt-32-3-a-new-cluster-and-a-precursor-for-three-well-known-clusters
#11
Esma Khatun, Atanu Ghosh, Debasmita Ghosh, Papri Chakraborty, Abhijit Nag, Biswajit Mondal, Sudhakar Chennu, Thalappil Pradeep
We report the synthesis of a new silver cluster, [Ag59(2,5-DCBT)32](3-) (I) (2,5-DCBT: 2,5-dichlorobenzenethiol), which acts as a precursor for the synthesis of three well-known silver clusters, [Ag44(2,4-DCBT/4-FTP)30](4-) (II) (4-FTP: 4-fluorothiophenol and 2,4-DCBT: 2,4-dichlorobenzenethiol), [Ag25(2,4-DMBT)18](-) (III) (2,4-DMBT: 2,4-dimethylbenzenethiol) and [Ag29(1,3-BDT)12(PPh3)4](3-) (IV) (1,3-BDT: 1,3-benzenedithiol and PPh3: triphenylphosphine). This newly synthesized silver cluster, I, is characterized using UV-vis absorption studies, high resolution electrospray ionization mass spectrometry (ESI MS) and other analytical tools...
June 5, 2017: Nanoscale
https://www.readbyqxmd.com/read/28573080/rapid-identification-of-psychoactive-drugs-in-drained-gastric-lavage-fluid-and-whole-blood-specimens-of-drug-overdose-patients-using-ambient-mass-spectrometry
#12
Chi-Wei Lee, Hung Su, You-Da Cai, Ming-Tsang Wu, Den-Chyang Wu, Jentaie Shiea
Psychoactive drug overdoses are life-threatening and require prompt and proper treatment in the emergency room to minimize morbidity and mortality. Prompt identification of the ingested psychoactive drugs is challenging, since witness recall is unreliable and patients' symptoms do not necessarily explain their loss of consciousness. Gas and liquid chromatography mass spectrometric analyses have been the traditionally employed methods to detect and identify abused substances; however, these techniques are time-consuming and labor-intensive...
2017: Mass Spectrometry
https://www.readbyqxmd.com/read/28570048/aerosol-mass-spectrometer-for-simultaneous-detection-of-polyaromatic-hydrocarbons-and-inorganic-components-from-individual-particles
#13
Johannes Passig, Julian Schade, Markus Oster, Matthias Fuchs, Sven Ehlert, Cornelia Jäger, Martin Sklorz, Ralf Zimmermann
Online studies of single airborne particles represent a demanding challenge in aerosol chemistry. New technologies that help to unravel the role of ambient aerosols in earth climate and to assess local and specific health risks from air pollution are highly desired. Of particular relevance are polycyclic aromatic hydrocarbons (PAHs) from combustion processes that are associated with both acute and long-term health effects. Usually, online single particle analyses apply laser desorption/ionization (LDI) in a bipolar mass spectrometer, revealing elemental constituents and limited molecular information by detection of both positive and negative ions...
June 9, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28540722/ultrafast-screening-and-quantitation-of-pesticides-in-food-and-environmental-matrices-by-solid-phase-microextraction-transmission-mode-spme-tm-and-direct-analysis-in-real-time-dart
#14
German Augusto Gómez-Ríos, Emanuela Gionfriddo, Justen J Poole, Janusz Pawliszyn
The direct interface of microextraction technologies to Mass Spectrometry (MS) has unquestionably revolutionized the speed and efficacy at which complex matrices are analyzed. Solid Phase Micro Extraction-Transmission Mode (SPME-TM) is a technology conceived as an effective synergy between sample preparation and ambient ionization. Succinctly, the device consists of a mesh coated with polymeric particles that extract analytes of interest present in a given sample matrix. This coated-mesh acts as a transmission mode substrate for Direct Analysis in Real Time (DART), allowing for rapid and efficient thermal-desorption/ionization of analytes previously concentrated on the coating, and dramatically lowering limits of detection attained by sole DART analysis...
May 25, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28535590/emission-of-volatile-organic-compounds-and-production-of-secondary-organic-aerosol-from-stir-frying-spices
#15
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...
December 1, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28530092/fibroblast-cytophilic-and-hela-cytotoxic-dual-function-carbon-nanoribbon-network-platform
#16
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 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 31, 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
#17
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 washing 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 improved the drug signal by as much as 2- to 25-fold in MSI, especially for hydrophobic compounds...
June 1, 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
#18
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
#19
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
#20
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
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