Read by QxMD icon Read

Journal of Mass Spectrometry: JMS

Juliette J Commodore, Carolyn J Cassady
The lanthanide ion praseodymium, Pr (III), was employed to study metallated ion formation and electron transfer dissociation (ETD) of twenty-seven biological and model highly acidic phosphopeptides. All phosphopeptides investigated form metallated ions by electrospray ionization (ESI) that can be studied by ETD to yield abundant sequence information. The ions formed are [M + Pr - H]2+ , [M + Pr]3+ , and [M + Pr + H]4+ . All biological phosphopeptide with a chain length of seven or more residues generate [M + Pr]3+ ...
September 17, 2018: Journal of Mass Spectrometry: JMS
Daiki Muko, Takanori Ikenaga, Masanori Kasai, Janice B Rabor, Atsushi Nishitani, Yasuro Niidome
For analysis of low abundance peptides in a tissue section, immunohistochemical staining through antibody-antigen interaction is a usual technique. The antibody is conjugated with a probe moiety that aids in highly sensitive detection. Gold nanoparticles, which show excellent chemical stability and variation of surface modifications, are expected to act as a sensitive mass probe to desorb gold ions (Au+ , Au2 + , Au3 + ) that are distinguishable from fragment ions from organic molecules. Here, green fluorescent proteins (GFP) in a tissue section of a transgenic zebrafish was detected by the gold mass probe conjugated with antibodies...
September 17, 2018: Journal of Mass Spectrometry: JMS
Tahereh Zargar, Mohammad T Jafari, Taghi Khayamian
In this work, a porous graphite sheet is introduced as the substrate in a spray ionization source for ion mobility spectrometry (PGSI-IMS), for the first time. This ionization source has some important advantages in comparison to the hollow needle, which is conventionally used in electrospray ionization. In order to prepare the hydrophilic surface needed to load samples on a graphite substrate, the graphite sheet was treated with hot sulfuric acid solution for 2 h. Some parameters affecting the ionization efficiency were studied and the optimized conditions were found to be 3...
September 17, 2018: Journal of Mass Spectrometry: JMS
Teng Guo, Zhen Peng, Xueshuang Li, Hui Zhu, Li Xu, Junguo Dong, Jialiang Feng, Ping Cheng, Zhen Zhou
Proton transfer reaction mass spectrometry (PTR-MS) is a mature technique for the real-time measurement and monitoring of volatile organic compounds (VOCs) in the atmosphere. In this paper, a modified quantification method for PTR-MS was used to assess the performance of non-thermal plasma (NTP) reactor for the removal of toluene which was widely used in industrial production processes. Toluene and eleven corresponding organic by-products were tentatively identified and quantified by a proton transfer reaction time-of-flight mass spectrometer...
September 12, 2018: Journal of Mass Spectrometry: JMS
Krista Vikse, J Scott McIndoe
The rapid development of new ionization methods has greatly expanded the ability of mass spectrometry to target diverse areas of chemistry. Synthetic organometallic and inorganic chemists often find themselves with interesting characterization problems that mass spectrometry could potentially find the answer for, but without a guide for choosing the appropriate method of analysis. This tutorial review seeks to provide that guidance via a simple flow chart followed by a brief description of how each common ionization method works...
September 5, 2018: Journal of Mass Spectrometry: JMS
Wilson D Shafer, Burtron H Davis
Industrial catalyst processes, such as the Fischer-Tropsch process produce a vast array of products from syngas (H2 /CO) such as; jet fuel, gasoline, diesel, synthetic rubbers, monomers for plastics industries and other oil/wax materials for specific purposes such as cosmetics. Multitudes of publications, since the discovery of the FT process in 1925, have been composed attempting to elucidate the mechanism. Many of these publications attempt to investigation the mechanism of FT by the utilization of specific deuterium experimentation through the switching of the syngas from H2 /CO to D2 /CO...
September 1, 2018: Journal of Mass Spectrometry: JMS
Jiří Novák, Anton Škríba, Jakub Zápal, Marek Kuzma, Vladimír Havlíček
Within the growing community of Fourier transform mass spectrometry users, the identification of fine isotope structure has become an indispensable method for molecular formula determination. In this work, the fine isotope envelopes for accessing the mutual ratio of two closely related pyoverdines in a mixture were used. Bacterial siderophores pyoverdines D and E cannot be easily separated via liquid chromatography-mass spectrometry because their structures differ in (de) amidation at the respective chromophore parts only...
August 30, 2018: Journal of Mass Spectrometry: JMS
Gabriela P Aguiar, Eduardo J Crevelin, Herbert J Dias, Sérgio R Ambrósio, Jairo K Bastos, Vladimir C G Heleno, Ricardo Vessecchi, Antônio E M Crotti
Copaifera (Leguminoseae) species produce a commercially interesting oleoresin that displays several biological activities, including antimicrobial and anti-inflammatory properties. Labdane-type diterpenes are the main chemical constituents of these oleoresins, and copalic acid is the only compound that has been detected in all Copaifera oleoresins. In this study, we investigate some aspects of the gas-phase fragmentation reactions involved in the formation of the product ions from the deprotonated compounds (-)-copalic acid (1), (-)-3β-hydroxy-copalic acid (2), (-)-3β-acetoxy-copalic acid (3), and (-)-ent-agathic acid (4) by electrospray ionization tandem mass spectrometry (ESI-MS/MS) and multiple stage mass spectrometry (MSn )...
August 17, 2018: Journal of Mass Spectrometry: JMS
Yi He, Jingzhu Wang, Mengzhen Wang, Jingfang Zhang
Musk is the dried secretion of the musk pod (sac) of adult male musk deer, and has been used as perfume and traditional medicine for thousands of years. Steroid was regarded as one of the most important active compounds in musk. In order to protect the wild musk deer, musk deer farming has been carried out in China, India, and Nepal. However, it is hard to differentiate the two origins of musk by morphological identification. No other method has been reported so far for the discrimination of wild and domestic deer musk...
August 17, 2018: Journal of Mass Spectrometry: JMS
Guillermo Moreiras, José Manuel Leão, Ana Gago-Martínez
Liquid Chromatography (LC) coupled to Mass Spectrometry (MS) is being widely applied as analytical tool in the field of marine biotoxins both for regulated and for new and emerging compounds. LC-MS/MS recently became the reference method for the control of lipophilic toxins in the European Union and new methods are being developed and optimized to extend the applicability of this technique to other toxin groups. In this work, conditions for the analysis of ciguatoxins (CTXs) by LC-MS/MS were investigated using standard solutions of CTX1B and CTX3C, which are structurally representative compounds for the rest of the main congeners of Pacific group toxins (P-CTXs)...
August 14, 2018: Journal of Mass Spectrometry: JMS
Edoardo Longo, Vakare Merkyte, Fabrizio Rossetti, Pierre-Louis Teissedre, Michael Jourdes, Emanuele Boselli
The identification of cyclic B-type procyanidins in grape and wine was recently disclosed. Some of these were also found in berries of totally different vegetal species (e.g. Vaccinium sp.). However, presence of a wider class of these cyclic condensed tannin compounds with variably substituted monomers has never been addressed so far. Here, an extended list of oligomeric cyclic proanthocyanidins (PAC) bearing variable substitution patterns on the main flavan-3-ol unit has been searched in wines. Nearly 7,600 theoretical structures were calculated and searched in red and white wine samples made from different grape varieties...
August 14, 2018: Journal of Mass Spectrometry: JMS
Cody D Sacks, Katherine A Stumpo
New applications for gold nanoparticles (AuNPs) in Laser Desorption Ionization Mass Spectrometry (LDI-MS) are presented here. This work expands on previous biomolecule studies and introduces carbohydrates, steroids, bile acids, and other small molecules as a focus. Broad trends in ionization are observed and specifically of interest are new species that have not previously been reported from AuNPs (e.g., [M+Au]+ ). Interesting fragmentation effects have been observed for diphenhydramine, including similarity to Electron Impact mass spectra and possible radical driven reactions, providing insight into the mechanism of ionization when using AuNPs...
August 14, 2018: Journal of Mass Spectrometry: JMS
Jördis-Ann Schüler, Steffen Neumann, Matthias Müller-Hannemann, Wolfgang Brandt
Identification and structural determination of small molecules by mass spectrometry is an important step in chemistry and biochemistry. However, the chemically realistic annotation of a fragment ion spectrum can be a difficult challenge. We developed ChemFrag, for the detection of fragmentation pathways and the annotation of fragment ions with chemically reasonable structures. ChemFrag combines a quantum chemical with a rule-based approach. For different doping substances as test instances, ChemFrag correctly annotates fragment ions...
August 13, 2018: Journal of Mass Spectrometry: JMS
Tajudheen K Karatt, Jahfar Nalakath, Zubair Perwad, Peter H Albert, K K Abdul Khader, M Syed Ali Padusha, S Laya
The major challenge in identifying dexamethasone, betamethasone, and paramethasone from a mixture of these corticosteroids is difficulty in achieving an efficient separation. In this study, we aimed to develop an efficient technique to identify these co-eluting isomers based on the mass spectral patterns of them and their corresponding phase II metabolites after electrospray ionization. Fragmentation pathways in tandem mass spectrometry revealed acceptable specificity within the groups of conjugates. The method was validated using individual isomers and mixtures at various compositions...
August 11, 2018: Journal of Mass Spectrometry: JMS
Junhai Yang, Jeremy L Norris, Richard Caprioli
We describe the use of aromatic ketones and cinnamyl ketones that have high vacuum stability for analyzing tissue sections using matrix-assisted laser desorption/ionization imaging mass spectrometry. Specifically, the matrix, (E)-4-(2,5-dihydroxyphenyl)but-3-en-2-one (2,5-cDHA) provides high sensitivity and high vacuum stability while producing small size crystals (1-2 μm). A high throughput and highly reproducible sample preparation method was developed for these matrices that first involves using an organic spray solution for small matrix crystal seeding followed by spraying of the matrix in a 30% acetonitrile/70% water solution on the tissue surface to obtain a homogeneous coating of small crystals, suitable for high spatial resolution imaging...
August 2, 2018: Journal of Mass Spectrometry: JMS
Andreas Riedo, Surya Rout, Reto Wiesendanger, Peter Wurz, Ingo Leya
The principles of operation and figures of merit of a novel, compact (324 mm x Ø 114 mm, volume ~1'000 cm3 ) reflectron-type time-of-flight mass spectrometer designed for simultaneous multi-element isotope gas analysis is presented. The system, which consists of a pulsed electron impact ion source, is designed either to directly analyse gas samples collected and stored in a compartment or samples extracted from solids using a CW laser system (fiber-coupled diode laser, < 75W, λ = 808 ± 10 nm). In latter case, laser pulses are focussed onto the sample surface to spot sizes of ~400 μm in diameter that allows for direct ablation and vaporisation of solid sample material and releasing of trapped gases...
August 1, 2018: Journal of Mass Spectrometry: JMS
Eugenio Aprea, Flavia Gasperi, Emanuela Betta, Graziano Sani, Claudio Cantini
A quantitative method, based on SPME GC-MS, for the quantification of volatile compounds derived from lipoxygenase pathway, considered the most important for the aroma of high-quality olive oil, was developed. The method was used to study the variation within the extra virgin olive oils from 67 cultivars of the Tuscan olive germplasm conserved at "Santa Paolina" experimental farm (Follonica, Italy). A great variability was observed among the 67 cultivars both for the total amount of volatile compounds and for the different ratios between the groups of volatile compounds from common precursors...
July 31, 2018: Journal of Mass Spectrometry: JMS
Gianluca Giorgi
No abstract text is available yet for this article.
July 30, 2018: Journal of Mass Spectrometry: JMS
Monika Polguj, Rafał Frański, Maciej Zalas, Błażej Gierczyk, Wojciech Jankowski, Marcin Hoffmann
No abstract text is available yet for this article.
July 23, 2018: Journal of Mass Spectrometry: JMS
Petra Cuřínová, Alena Krupková, Lucie Červenková Šťastná, Monika Müllerová, Jan Čermák, Tomáš Strašák
Macromolecular polyelectrolytes are gaining considerable attention for the application in medicine that implies their detailed characterization. We have successfully applied electrospray ionization mass spectrometry (ESI MS) to the analysis of defects in the structure of three generations of polycationic carbosilane dendrimers bearing series of quarternary phosphonium groups at their periphery. Besides expected defects caused by incomplete conversion of particular reaction steps during the synthesis of dendritic scaffold and subsequent peripheral functionalization, also, several products of side reactions were observed together with defects created in the course of measurement (particularly ion exchange products)...
July 17, 2018: Journal of Mass Spectrometry: JMS
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"