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Ambient ionization

Rahul Narayanan, Thalappil Pradeep
Fragile transition metal complex ions such as [Cr(H2O)4Cl2]+, difficult to be observed by gas phase spectroscopy, are detected easily with carbon nanotube (CNT) assisted low voltage ambient ionization mass spectrometry. Observation of various substituted ions with D2O and ROH (R = CH3, C2H5…) established the versatility of the technique in detecting diverse species. Ligand substitution occurring in solution was captured by the low voltage technique. Extreme softness of the technique coupled with nanoscale ion sources enabled the creation of such species...
September 20, 2017: Analytical Chemistry
Patrick W Fedick, Brandon J Bills, Nicholas E Manicke, R Graham Cooks
Sample preparation is the most common bottle-neck in the analysis and processing of forensic evidence. Time-consuming steps in many forensic tests involve complex separations such as liquid and gas chromatography or various types of extraction techniques, typically coupled with mass spectrometry (e.g. LC-MS). Ambient ionization ameliorates these slow steps by reducing or even eliminating sample preparation. While some ambient ionization techniques have been adopted by the forensic community, there is significant resistance to discarding chromatography as most forensic analyses require both an identification and a confirmation technique...
September 19, 2017: Analytical Chemistry
Austen L Davis, Brian H Clowers
Significant challenges exist when characterizing f-element complexes in solution using traditional approaches such as electrochemical and spectroscopic techniques as they do not always capture information for lower abundance species. However, provided a metal-complex with sufficient stability, soft ionization techniques such as electrospray offer a means to quantify and probe the characteristics of such systems using mass spectrometry. Unfortunately, the gas-phase species observed in ESI-MS systems do not always reflect the solution phase distributions due to the inherent electrochemical mechanism of the electrospray process, ion transfer from ambient to low pressures conditions, and other factors that are related to droplet evaporation...
January 1, 2018: Talanta
Xiangrui Kong, Astrid Waldner, Fabrizio Orlando, Luca Artiglia, Thomas Huthwelker, Markus Ammann, Thorsten Bartels-Rausch
The interfacial ionization of strong acids is an essential factor of multi-phase and heterogeneous chemistry in environmental science, crysophereic science, catalysis research and material science. We investigate the mechanism of HCl dissociation at the ice surface using surface-sensitive ambient-pressure core level X-ray photoelectron spectroscopy. At 253 K and low surface coverage, adsorbed HCl is found in both states, molecular and dissociated. Depth profiles derived from XPS data clearly show that the dissociated acid is found deeper in the interfacial region compared to the molecular form...
September 13, 2017: Journal of Physical Chemistry Letters
Stefanie Gerbig, Stephan Neese, Alexander Penner, Bernhard Spengler, Sabine Schulz
Food adulteration is a threat to public health and economy. In order to determine food adulteration efficiently, rapid and easy-to-use on-site analytical methods are needed. In this study, a miniaturized mass spectrometer in combination with three ambient ionization methods was used for food authentication. The chemical fingerprints of three milk types, five fish species and two coffee types were measured using electrospray ionization, desorption electrospray ionization and low temperature plasma ionization...
September 11, 2017: Analytical Chemistry
Keaton S Nahan, Noe Alvarez, Vesselin Shanov, Anne Vonderheide
Mass spectrometry continues to tackle many complicated tasks, and ongoing research seeks to simplify its instrumentation as well as sampling. The desorption electrospray ionization (DESI) source was the first ambient ionization source to function without extensive gas requirements and chromatography. Electrospray techniques generally have low efficiency for ionization of nonpolar analytes and some researchers have resorted to methods such as direct analysis in real time (DART) or desorption atmospheric pressure chemical ionization (DAPCI) for their analysis...
September 7, 2017: Journal of the American Society for Mass Spectrometry
A Murray Booth, Thomas J Bannan, Med Benyezzar, Asan Bacak, M Rami Alfarra, David Topping, Carl J Percival
Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting, sensitive and robust method for the detection of volatile species in the gas phase. The design, manufacture and results of lithium based ion attachment ionisation sources for two different mass spectrometry systems are presented. In this study trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure measurements are made using a modified Knudsen Effusion Mass Spectrometer (KEMS)...
September 7, 2017: Analyst
Sampad Bag, Sankhabrata Chandra, Atanu Bhattacharya
Molecular attosecond science has already started contributing to our fundamental understanding of ultrafast purely electron dynamics in isolated molecules under vacuum. Extending attosecond science to the liquid phase is expected to offer new insight into the influence of a surrounding solvent environment on the attosecond electron dynamics in solvated molecules. A systematic theoretical investigation of the attochemistry of solvated molecules would help one design attosecond experiments under ambient conditions to explore the attochemistry in a liquid environment...
September 6, 2017: Physical Chemistry Chemical Physics: PCCP
Shaodong Zhou, Marjan Firouzbakht, Maria Schlangen, Martin Kaupp, Helmut Schwarz
The gas-phase reactions of [NiL](+) (L=C6 H5 , C5 H4 N, CN) with methane have been explored by using electrospray-ionization mass spectrometry (ESI-MS) complemented by quantum chemical calculations. Though the phenyl Ni complex [Ni(C6 H5 )](+) exclusively abstracts one hydrogen atom from methane at ambient conditions, the cyano Ni complex [Ni(CN)](+) brings about both H-atom abstraction and ligand exchange to generate [Ni(CH3 )](+) . In contrast, the complex 2-pyridinyl Ni [Ni(C5 H4 N)](+) is inert towards this substrate...
September 1, 2017: Chemistry: a European Journal
Måns Ekelöf, David C Muddiman
In the field of mass spectrometry imaging, typical experiments involve ionization directly from complex samples with no pre-ionization separation, relying on high resolving power mass analyzers to separate ions of interest. When an ion trapping step is involved in the analysis, the dynamic range of the analysis may be limited by the capacity of the ion trap, which is easily exceeded. To minimize collection of undesired ambient species while maximizing collection of analyte signal, accurate timing between ion generation and collection is a requirement...
August 29, 2017: Analytical and Bioanalytical Chemistry
Wenpeng Zhang, Xiao Wang, Yu Xia, Zheng Ouyang
Mass spectrometry has become a powerful tool in the field of biomedicine. The combination of ambient ionization and miniature mass spectrometry systems could most likely fulfill a significant need in medical diagnostics, providing highly specific molecular information in real time for clinical and even point-of-care analysis. In this review, we discuss the recent development of ambient ionization and miniature mass spectrometers as well as their potential in disease diagnosis and therapeutic monitoring, with an emphasis on their capability in analysis of biofluids and tissues...
2017: Theranostics
Donghwi Kim, Un Hyuk Yim, Byungjoo Kim, Sangwon Cha, Sunghwan Kim
Sensitivity is an important factor determining successful mass spectrometry (MS) analysis of metabolome, protein, drugs, and environmental samples. Currently, nanoelectrospray ionization (ESI) is widely used as a sensitive ionization method. However, application of nano-ESI is limited to polar molecules and there is no atmospheric pressure ionization technique developed that can be used for MS analysis of low- and nonpolar compounds with sensitivity that can match with nano-ESI. Herein, we propose paper spray chemical ionization (PSCI) as an ionization technique that can be used to analyze low- and nonpolar aromatic compounds with high sensitivity...
September 5, 2017: Analytical Chemistry
Kyle D Duncan, Hilde-Marléne Bergman, Ingela Lanekoff
Nanospray desorption electrospray ionization (nano-DESI) has been established as a powerful technique for mass spectrometry imaging (MSI) of biomolecules from tissue samples. The direct liquid extraction of analytes from a surface at ambient pressure negates the need for significant sample preparation or matrix application. Although many recent studies have applied nano-DESI to new and exciting applications, there has not been much work in the development and improvement of the nano-DESI source. Here, we incorporate a nebulizer to replace the self-aspirating secondary capillary in the conventional nano-DESI setup, and characterize the device by use of rat kidney tissue sections...
August 22, 2017: Analyst
Yumi Hayashi, Kei Zaitsu, Tasuku Murata, Tomomi Ohara, Stéphane Moreau, Maiko Kusano, Hiroshi Tanihata, Hitoshi Tsuchihashi, Akira Ishii, Tetsuya Ishikawa
Probe electrospray ionization (PESI), which is an ambient ionization technique, enables us to analyze intact endogenous metabolites without sample preparation. In this study, we applied the newly developed method of PESI coupled to tandem mass spectrometry (PESI/MS/MS) to analyze metabolites in mouse brain, where its lipid composition often interfere with MS-based metabolome analysis. As a result, PESI/MS/MS directly detected 25 metabolites in a mouse frontal cortex, and clearly discriminated the metabolic profiles of mice model with energy metabolism disruption from control mice...
August 29, 2017: Analytica Chimica Acta
Chaevien S Clendinen, María Eugenia Monge, Facundo M Fernández
Since the introduction of desorption electrospray ionization (DESI) mass spectrometry (MS), ambient MS methods have seen increased use in a variety of fields from health to food science. Increasing its popularity in metabolomics, ambient MS offers limited sample preparation, rapid and direct analysis of liquids, solids, and gases, in situ and in vivo analysis, and imaging. The metabolome consists of a constantly changing collection of small (<1.5 kDa) molecules. These include endogenous molecules that are part of primary metabolism pathways, secondary metabolites with specific functions such as signaling, chemicals incorporated in the diet or resulting from environmental exposures, and metabolites associated with the microbiome...
August 9, 2017: Analyst
Sambhav R Kumbhani, Lisa M Wingen, Véronique Perraud, Barbara J Finlayson-Pitts
RATIONALE: Ambient ionization mass spectrometry methods are convenient, sensitive and require little sample preparation. However, they are susceptible to species present in air surrounding the mass spectrometer. This study identifies some challenges associated with the potential impacts of indoor air contaminants on ionization and analysis involving open air methods. METHODS: Unexpected effects of volatile organic compounds from floor maintenance activities on ambient ionization mass spectrometry were studied using three different ambient ionization techniques...
August 6, 2017: Rapid Communications in Mass Spectrometry: RCM
Cong-Min Huang, Ying Zhu, Di-Qiong Jin, Ryan T Kelly, Qun Fang
Ambient mass spectrometry (MS) has revolutionized the way of MS analysis and broadened its application in various fields. This paper describes the use of microfluidic techniques to simplify the setup and improve the functions of ambient MS by integrating the sampling probe, electrospray emitter probe, and online mixer on a single glass microchip. Two types of sampling probes, including a parallel-channel probe and a U-shaped channel probe, were designed for dry-spot and liquid-phase droplet samples, respectively...
September 5, 2017: Analytical Chemistry
Lucia Mainero Rocca, Juri Cecca, Nunziata L'Episcopo, Giovanni Fabrizi
A new field of application for a relatively new mass-spectrometric interface such as desorption electrospray ionization was evaluated. For this purpose, its behavior was tested versus quantitative analysis of dimethoate, trifloxystrobin and tebuconazole directly on olive and vine leaves surface. The goal was workers exposure assessment during field re-entry operations since evidence suggests an association between chronic occupational exposure to some agrochemicals and severe adverse effects. DESI gave good response working in positive ionization mode, while numerous test were necessary for the choice of a unique blend of spray solvents suitable for all three substances...
August 1, 2017: Journal of Mass Spectrometry: JMS
Son N Nguyen, Ryan L Sontag, James P Carson, Richard A Corley, Charles Ansong, Julia Laskin
Constant mode ambient mass spectrometry imaging (MSI) of tissue sections with high lateral resolution of better than 10 μm was performed by combining shear force microscopy with nanospray desorption electrospray ionization (nano-DESI). Shear force microscopy enabled precise control of the distance between the sample and nano-DESI probe during MSI experiments and provided information on sample topography. Proof-of-concept experiments were performed using lung and brain tissue sections representing spongy and dense tissues, respectively...
July 28, 2017: Journal of the American Society for Mass Spectrometry
Damila Rodrigues de Morais, Ingrid Lopes Barbosa, Kelly Francisco Cunha, Guilherme Lucas Tripodi, Célio Fernando Figueiredo Angolini, Marcos Fernando Franco, Elvis Medeiros de Aquino, Marcos Nogueira Eberlin, Jose Luiz Costa
The increasing number of new psychoactive substances (NPS) and their quick worldwide spreading, often only slightly modified in the form of new derivatives and analogues, have brought the need for fast, wide-ranging and unequivocal identification methods in clinical and forensic investigations. Since it usually provides secure results, gas chromatography coupled to mass spectrometry (GC-MS) has been routinely employed as the standard technique for the detection of NPS in blotter papers. For 25I-NBOH (N-(2-hydroxybenzyl)-2-(4-iodo-2,5-dimethoxyphenyl)ethan-1-aminium), however, GC-MS analysis of an blotter paper extract leads to incorrect results...
July 26, 2017: Journal of Mass Spectrometry: JMS
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