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Ambient ionization

Kenion H Blakeman, Craig A Cavanaugh, William M Gilliland, J Michael Ramsey
RATIONALE: There are many chemical measurement scenarios that would benefit from hand portable mass spectrometry tools including forensics, environmental monitoring, and safety and security. High pressure mass spectrometry (HPMS) facilitates miniaturization by significantly reducing vacuum system requirements. Previous work demonstrated HPMS using helium buffer gas, but HPMS conducted using ambient air would further reduce the size and weight of a portable instrument while also reducing logistical demands by eliminating the need for a helium supply...
October 17, 2016: Rapid Communications in Mass Spectrometry: RCM
Bilu Xiang, Yang Liu, Lu Xie, Qian Zhao, Ling Zhang, Xueqi Gan, Haiyang Yu
Osteoclasts demineralize and resorb bone once they attach to its surface. However, it's still unclear how the osteoclasts choose the specific sites for their attachments. It is postulated in this article that the decreased extracellular free ionized calcium concentration (Ca(2+)[e]) can provide a microenvironment for osteoclasts to recognize and then initiate the attachment process. The osteoclasts initially attach to the bone surface via integrating its integrin αvβ3 and RGD containing ligands in bone matrix...
October 7, 2016: Cell Biochemistry and Biophysics
Lalita B Rane, Anup N Kate, Shefali N Ramteke, Bhupendra V Shravage, Prasad P Kulkarni, Anupa A Kumbhar
Two new zinc(ii) complexes, [Zn(l-His)(NIP)](+)(1) and [Zn(acac)2(NIP)](2) (where NIP is 2-(naphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, acac = acetyl acetone), have been synthesized and characterized by elemental analysis, UV-vis, fluorescence, IR, (1)H NMR and electron spray ionization mass spectroscopies. Gel retardation assay, atomic force microscopy and dynamic light scattering studies show that 1 and 2 can induce the condensation of circular plasmid pBR322 DNA into nanometer size particles under ambient conditions...
October 3, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Alexander L Vogel, Johannes Schneider, Christina Müller-Tautges, Thomas Klimach, Thorsten Hoffmann
Atmospheric oxidation of volatile organic compounds (VOCs) yields a large number of different organic molecules which comprise a wide range of volatility. Depending on their volatility, they can be involved in new particle formation and particle growth, thus affecting the number concentration of cloud condensation nuclei in the atmosphere. Here, we identified oxidation products of VOCs in the particle phase during a field study at a rural mountaintop station in central Germany. We used atmospheric pressure chemical ionization mass spectrometry ((-)APCI-MS) and aerosol mass spectrometry for time-resolved measurements of organic species and of the total organic aerosol (OA) mass in the size range of 0...
October 6, 2016: Environmental Science & Technology
Anna Maria A P Fernandes, Pedro H Vendramini, Renan Galaverna, Nicolas V Schwab, Luciane C Alberici, Rodinei Augusti, Roger F Castilho, Marcos N Eberlin
Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials...
October 4, 2016: Journal of the American Society for Mass Spectrometry
Shuting Xu, Yiding Zhang, Linnan Xu, Yu Bai, Huwei Liu
Since ambient mass spectrometry (AMS) has been proven to have low matrix effects and high salt tolerance, great efforts have been made for online coupling of several analytical techniques with AMS. These analytical techniques include gas chromatography (GC), liquid chromatography (LC), capillary electrophoresis (CE), surface plasmon resonance (SPR), and electrochemistry flow cells. Various ambient ionization sources, represented by desorption electrospray ionization (DESI) and direct analysis in real time (DART), have been utilized as interfaces for the online coupling techniques...
October 17, 2016: Analyst
Hang Li, Pranav Balan, Akos Vertes
Metabolism in microbial colonies responds to competing species, rapidly evolving genetic makeup, and sometimes dramatic environmental changes. Conventional characterization of the existing and emerging microbial strains and their interactions with antimicrobial agents, e.g., the Kirby-Bauer susceptibility test, relies on time consuming methods with limited ability to discern the molecular mechanism and the minimum inhibitory concentration. Assessing the metabolic adaptation of microbial colonies requires their non-targeted molecular imaging in a native environment...
October 4, 2016: Angewandte Chemie
T D Li, F Liu, Y X Xie, J H Chen
Objective: To establish solvent desorption gas chromatographic method for determination of tert-butyl alcohol in the air of the workplace. Methods: After tert-butyl alcohol in the air of the workplace collected with activated carbon tube and desorbed with 2% 2-propanol in CS2, and then separated with DB-FFAP capillary column and detected with flame ionization detector. Results: The linearity ranges were 0.6~2 264.0 mg/L. The limit of quantification was 0.6 mg/L. The determination has a good reproducibility...
August 20, 2016: Chinese Journal of Industrial Hygiene and Occupational Diseases
Basil M Ahmed, Christian K Hartman, Gellert Mezei
A series of 9 homologous sulfate-incarcerating nanojars [SO4⊂{Cu(OH)(pz)}n](2-) (Cun; n = 27-33; pz = pyrazolate), based on combinations of three [Cu(OH)(pz)]x rings (x = 6-14, except 11)-namely, 6 + 12 + 9 (Cu27), 6 + 12 + 10 (Cu28), 8 + 13 + 8 (Cu29), 7 + 13 + 9 (Cu29), 8 + 14 + 8 (Cu30), 7 + 14 + 9 (Cu30), 8 + 14 + 9 (Cu31), 8 + 14 + 10 (Cu32), and 9 + 14 + 10 (Cu33)-has been obtained and characterized by electrospray-ionization mass spectrometry (ESI-MS), variable-temperature (1)H NMR spectroscopy, and thermogravimetry...
October 17, 2016: Inorganic Chemistry
Shibdas Banerjee, Chanbasha Basheer, Richard N Zare
We have developed nanoparticle-embedded paper-spray mass spectrometry for studying three types of heterogeneously catalyzed reactions: 1) Palladium-nanoparticle-catalyzed Suzuki cross-coupling reactions, 2) palladium- or silver-nanoparticle-catalyzed 4-nitrophenol reduction, and 3) gold-nanoparticle-catalyzed glucose oxidation. These reactions were almost instantaneous on the nanocatalyst-embedded paper, which subsequently transferred the transient intermediates and products to a mass spectrometer for their detection...
October 4, 2016: Angewandte Chemie
Livia S Eberlin, Katherine Margulis, Ivette Planell-Mendez, Richard N Zare, Robert Tibshirani, Teri A Longacre, Moe Jalali, Jeffrey A Norton, George A Poultsides
BACKGROUND: Surgical resection with microscopically negative margins remains the main curative option for pancreatic cancer; however, in practice intraoperative delineation of resection margins is challenging. Ambient mass spectrometry imaging has emerged as a powerful technique for chemical imaging and real-time diagnosis of tissue samples. We applied an approach combining desorption electrospray ionization mass spectrometry imaging (DESI-MSI) with the least absolute shrinkage and selection operator (Lasso) statistical method to diagnose pancreatic tissue sections and prospectively evaluate surgical resection margins from pancreatic cancer surgery...
August 2016: PLoS Medicine
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
Si Cheng, Qiuhua Wu, Howard D Dewald, Hao Chen
Online detection of methanol electro-oxidation reaction products [e.g., formaldehyde (HCHO)] by mass spectrometry (MS) is challenging, owing to the high salt content and extreme pH of the electrolyte solution as well as the difficulty in ionizing the reaction products. Herein we present an online ambient mass spectrometric approach for analyzing HCHO generated from methanol electro-oxidation, taking the advantage of high salt tolerance of desorption electrospray ionization mass spectrometry (DESI-MS). It was found that HCHO can be detected as PhNHNH(+)=CH2 (m/z 121) by DESI after online derivatization with PhNHNH2...
August 25, 2016: Journal of the American Society for Mass Spectrometry
Bin Jia, Shuai Zhang, Ling Yan, Shoubo He, Baohong Liu, Huali Shen, Pengyuan Yang
RATIONALE: Extractive electrospray ionization mass spectrometry (EESI-MS) was invented as a typical ambient mass spectrometry method (AMS) and has been used for analyzing complex liquid samples. Here, we designed a Venturi effect-based self-aspiration sampling device and applied it to the EESI-MS for high-throughput analysis of liquid sample. METHODS: A special concentric nebulizer was designed and employed to produce a suction force for the direct aspiration of liquid samples, followed by ionization and detection...
August 2016: Rapid Communications in Mass Spectrometry: RCM
Daniel G Beach, Callee M Walsh, Pamela Cantrell, Wade Rourke, Sinead O'Brien, Kelley Reeves, Pearse McCarron
RATIONALE: Domoic acid (DA) is a potent neurotoxin that accumulates in shellfish. Routine testing involves homogenization, extraction and chromatographic analysis, with a run time of up to 30 min. Improving throughput using ambient ionization for direct analysis of DA in tissue would result in significant time savings for regulatory testing labs. METHODS: We assess the suitability of laser ablation electrospray ionization high-resolution mass spectrometry (LAESI-HRMS) for high-throughput screening or quantitation of DA in a variety of shellfish matrices...
November 30, 2016: Rapid Communications in Mass Spectrometry: RCM
F D Klute, A Schütz, A Michels, C Vadla, D Veza, V Horvatic, J Franzke
While the influence of trace impurities in noble gas discharges is well established in theoretical work, experimental approaches are difficult. Particularly the effects of trace concentrations of N2 on He discharges are complicated to investigate due to the fact that for He 5.0 the purity of He is only 99.999%. This corresponds to a residual concentration of 10 ppm, thereof 3 ppm of N2, in He. Matters are made difficult by the fact that He DBD plasmajets are normally operated under an ambient atmosphere, which has a high abundance of N2...
October 21, 2016: Analyst
Wilco F Duvivier, Teris A van Beek, Michel W F Nielen
RATIONALE: Recently, several direct and/or ambient mass spectrometry (MS) approaches have been suggested for drugs of abuse imaging in hair. The use of mass spectrometers with insufficient selectivity could result in false-positive measurements due to isobaric interferences. Different mass analyzers have been evaluated regarding their selectivity and sensitivity for the detection of Δ9-tetrahydrocannabinol (THC) from intact hair samples using direct analysis in real time (DART) ionization...
November 15, 2016: Rapid Communications in Mass Spectrometry: RCM
Maria Elisa Melo Branco de Araújo, Paula Renata Bueno Campos, Thiago Grando Alberto, Fabiano Jares Contesini, Patrícia de Oliveira Carvalho
The search for new biocatalysts has aroused great interest due to the variety of micro-organisms and their role as enzyme producers. Native lipases from Aspergillus niger and Rhizopus javanicus were used to enrich the n-3 long-chain polyunsaturated fatty acids content in the triacylglycerols of soybean oil by acidolysis with free fatty acids from sardine oil in solvent-free media. For the immobilization process, the best lipase/support ratios were 1:3 (w/w) for Aspergillus niger lipase and 1:5 (w/w) for Rhizopus javanicus lipase using Amberlite MB-1...
October 2016: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
Peerzada Y Yousuf, Arshid H Ganie, Ishrat Khan, Mohammad I Qureshi, Mohamed M Ibrahim, Maryam Sarwat, Muhammad Iqbal, Altaf Ahmad
Carbon (C) and nitrogen (N) are two essential elements that influence plant growth and development. The C and N metabolic pathways influence each other to affect gene expression, but little is known about which genes are regulated by interaction between C and N or the mechanisms by which the pathways interact. In the present investigation, proteome analysis of N-efficient and N-inefficient Indian mustard, grown under varied combinations of low-N, sufficient-N, ambient [CO2], and elevated [CO2] was carried out to identify proteins and the encoding genes of the interactions between C and N...
2016: Frontiers in Plant Science
Elizabeth A Crawford, Cemal Esen, Dietrich A Volmer
Direct in-droplet (in stillo) microreaction monitoring using acoustically levitated micro droplets has been achieved by combining acoustic (ultrasonic) levitation for the first time with real time ambient tandem mass spectrometry (MS/MS). The acoustic levitation and inherent mixing of microliter volumes of reactants (3 μL droplets), yielding total reaction volumes of 6 μL, supported monitoring the acid-catalyzed degradation reaction of erythromycin A. This reaction was chosen to demonstrate the proof-of-principle of directly monitoring in stillo microreactions via hyphenated acoustic levitation and ambient ionization mass spectrometry...
September 6, 2016: Analytical Chemistry
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