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Mass Spectrometry

Takashi Baba, J Larry Campbell, J C Yves Le Blanc, Paul R S Baker, James W Hager, Bruce A Thomson
Collision-induced dissociation (CID) is the most common tool for molecular analysis in mass spectrometry to date. However, there are difficulties associated with many applications because CID does not provide sufficient information to permit details of the molecular structures to be elucidated, including post-translational-modifications in proteomics, as well as isomer differentiation in metabolomics and lipidomics. To face these challenges, we are developing fast electron-based dissociation devices using a novel radio-frequency ion trap (i...
2017: Mass Spectrometry
Thierry Fouquet, Laurence Charles, Hiroaki Sato
Ethoxy-, methoxy- and hydroxy-terminated polydimethylsiloxanes (PDMS) are formed as the result of the methanolysis of diethoxy-ended PDMS during its infusion in electrospray ionization. The negative ion mode permits only hydroxy-ended products to be detected, and isomeric interference is avoided in single stage and tandem mass spectrometry. The routes for the fragmentation of (ethyl, hydroxy)-, (methyl, hydroxy)- and (hydro, hydroxy)-ended PDMS upon collision activated dissociation (CAD) were explored in the negative ion mode using either formate or acetate anion adduction...
2017: Mass Spectrometry
Fumio Matsuda, Atsumi Tomita, Hiroshi Shimizu
In targeted proteomics using liquid chromatography-tandem triple quadrupole mass spectrometry (LC/MS/MS) in the selected reaction monitoring (SRM) mode, selecting the best observable or visible peptides is a key step in the development of SRM assay methods of target proteins. A direct comparison of signal intensities among all candidate peptides by brute-force LC/MS/MS analysis is a concrete approach for peptide selection. However, the analysis requires an SRM method with hundreds of transitions. This study reports on the development of a method for predicting and identifying hopeless peptides to reduce the number of candidate peptides needed for brute-force experiments...
2017: Mass Spectrometry
Thierry Fouquet, Hiroaki Sato
The concept of a fractional base unit for the Kendrick mass defect (KMD) analysis of polymer ions is introduced for the first time. A fraction of the ethylene oxide (EO) repeat unit (namely EO/8) has been used for the KMD analysis of a poly(ethylene oxide) and found to amplify the variations of KMD between monoisotopic and (13)C isotopes, producing an isotopically resolved KMD plot at full scale when the KMD plot computed with EO is fuzzy. The expansion of the KMD dimension using a fractional base unit has then been successfully used to unequivocally discriminate all the distributions from a blend of poly(ethylene oxide)s in a high resolution KMD plot calculated with EO/3 as base unit...
2017: Mass Spectrometry
Sy-Chyi Cheng, Shih-His Chen, Jentaie Shiea
Flame-induced atmospheric pressure chemical ionization (FAPCI) is a solvent and high voltage-free APCI technique. It uses a flame to produce charged species that reacts with analytes for ionization, and generates intact molecular ions from organic compounds with minimal fragmentation. In this study, desorption FAPCI/MS was developed to rapidly characterize thermally stable organic compounds in liquid, cream, and solid states. Liquid samples were introduced into the ion source through a heated nebulizer, and the analytes formed in the heated nebulizer reacted with charged species in the source...
2017: Mass Spectrometry
Jen-Yi Hsu, Chia-Lung Shih, Pao-Chi Liao
Phthalates are chemicals widely used in industry and the consequences on human health caused by exposure to these agents are of significant interest currently. The urinary metabolites of phthalates can be measured and used as exposure markers for the assessment of the actual internal contamination of phthalates coming from different sources and absorbed by various ways. The purpose of this paper is to review the markers for exposure and risk assessment of phthalates such as di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl)phthalate (DEHP), di-(2-propylheptyl)phthalate (DPHP), di-iso-nonyl phthalate (DINP), di-n-octyl phthalate (DnOP) and di-iso-decyl phthalate (DIDP), and introduction of the analytical approach of three metabolomics data processing approaches that can be used for chemical exposure marker discovery in urine with high-resolution mass spectrometry (HRMS) data...
2017: Mass Spectrometry
Anil Kumar Meher, Yu-Chie Chen
Generation of analyte ions in gas phase is a primary requirement for mass spectrometric analysis. One of the ionization techniques that can be used to generate gas phase ions is electrospray ionization (ESI). ESI is a soft ionization method that can be used to analyze analytes ranging from small organics to large biomolecules. Numerous ionization techniques derived from ESI have been reported in the past two decades. These ion sources are aimed to achieve simplicity and ease of operation. Many of these ionization methods allow the flexibility for elimination or minimization of sample preparation steps prior to mass spectrometric analysis...
2017: Mass Spectrometry
Yu-Min Juang, Han-Ju Chien, Cheng-Yu Yang, Hsiao-Chien Yeh, Tsun-Jen Cheng, Chien-Chen Lai
Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanomaterials in consumer products and industrial applications. As a result of all these uses, this has raised concerns regarding their potential toxicity. We previously found that candidate markers of idiopathic pulmonary fibrosis and lung cancer were significantly up-regulated in rat bronchoalveolar lavage fluid (BALF) following exposure to ZnO NPs by using a liquid chromatography (LC)-based proteomic approach. To achieve comprehensive protein identification analysis, we conducted the two-dimensional gel electrophosis (2-DE)-based proteomic workflow to analyze the differences in BALF proteins from rats that had been exposed to a high dose of 35 nm ZnO NPs...
2017: Mass Spectrometry
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
Pao-Chi Liao, Jentaie Shiea
No abstract text is available yet for this article.
2017: Mass Spectrometry
Pei-Lun Tsai, Sung-Fang Chen
The purpose of this review is to provide updated information regarding bioinformatic software for the use in the characterization of glycosylated structures since 2013. A comprehensive review by Woodin et al.Analyst 138: 2793-2803, 2013 (ref. 1) described two main approaches that are introduced for starting researchers in this area; analysis of released glycans and the identification of glycopeptide in enzymatic digests, respectively. Complementary to that report, this review focuses on mass spectrometry related bioinformatics tools for the characterization of N-linked and O-linked glycopeptides...
2017: Mass Spectrometry
Yu-Ching Liu, Chao-Jung Chen
We developed a rapid and simple approach without using complex mechanical or chemical protocols to fabricate boronic acid-functionalized plates for glycoprotein or glycopeptide enrichment and mass spectrometry (MS) analysis. By coating the boronic acid-functionalized silica particles on a polydimethylsiloxane (PDMS)-coated matrix-assisted laser desorption/ionization (MALDI) plate, these particles can form a firmly monolayer of particles on PDMS membrane for sample handling without peeling off. The boronic acid particles-coated PDMS plate (BP plate) was successfully applied to the enrichment of horseradish peroxidase (HRP) protein and their digested glycopeptides...
2017: Mass Spectrometry
Ya-Ru Tang, Hui-Hsien Yang, Pawel L Urban
Chemical analysis of complex matrices-containing hundreds of compounds-is challenging. Two-dimensional separation techniques provide an efficient way to reduce complexity of mixtures analyzed by mass spectrometry (MS). For example, gasoline is a mixture of numerous compounds, which can be fractionated by distillation techniques. However, coupling conventional distillation with other separations as well as MS is not straightforward. We have established an automatic system for online coupling of simple microscale distillation with gas chromatography (GC) and electron ionization MS...
2017: Mass Spectrometry
Li-Hua Li, Hua-Yi Hsieh, Cheng-Chih Hsu
Ambient ionization allows mass spectrometry analysis directly on the sample surface under atmospheric pressure with almost zero sample pretreatment. Since the development of desorption electrospray ionization (DESI) in 2004, many other ambient ionization techniques were developed. Due to their simplicity and low operation cost, rapid and on-site clinical mass spectrometry analysis becomes real. In this review, we will highlight some of the most widely used ambient ionization mass spectrometry approaches and their applications in clinical study...
2017: Mass Spectrometry
Dilshadbek Tursunbayevich Usmanov, Satoshi Ninomiya, Lee Chuin Chen, Subhrakanti Saha, Mridul Kanti Mandal, Yuji Sakai, Rio Takaishi, Ahsan Habib, Kenzo Hiraoka, Kentaro Yoshimura, Sen Takeda, Hiroshi Wada, Hiroshi Nonami
In mass spectrometry, analytes must be released in the gas phase. There are two representative methods for the gasification of the condensed samples, i.e., ablation and desorption. While ablation is based on the explosion induced by the energy accumulated in the condensed matrix, desorption is a single molecular process taking place on the surface. In this paper, desorption methods for mass spectrometry developed in our laboratory: flash heating/rapid cooling, Leidenfrost phenomenon-assisted thermal desorption (LPTD), solid/solid friction, liquid/solid friction, electrospray droplet impact (EDI) ionization/desorption, and probe electrospray ionization (PESI), will be described...
2017: Mass Spectrometry
Jen-Ying Liu, Pei-Chun Chen, Yea-Wenn Liou, Kai-Yin Chang, Cheng-Huang Lin
The development of a novel type of a sampling/ionization kit for use in electrospray ionization/mass spectrometry is reported. Using a small calligraphy-brush-style synthetic hair pen (nylon-brush), and analogous to paper-spray mass spectrometry, the analytes can be collected, elution/desorption and then ionized from the surface of the nylon-brush. The body of the kit was produced by means of a commercial 3D-printer, in which ABS (acrylonitrile butadiene styrene) was used as the starting material. Meanwhile, a small nylon-brush was embedded inside a 3D-printed plastic cell, in which a solvent was supplied to rinse the brush by means of capillary action...
2017: Mass Spectrometry
Yuichiro Hashimoto
The development of a robust ionization source using the counter-flow APCI, miniature mass spectrometer, and an automated sampling system for detecting explosives are described. These development efforts using mass spectrometry were made in order to improve the efficiencies of on-site detection in areas such as security, environmental, and industrial applications. A development team, including the author, has struggled for nearly 20 years to enhance the robustness and reduce the size of mass spectrometers to meet the requirements needed for on-site applications...
2017: Mass Spectrometry
Satoshi Ninomiya, Kentaro Yoshimura, Lee Chuin Chen, Sen Takeda, Kenzo Hiraoka
Tissue samples from renal cell carcinoma patients were analyzed by electrospray droplet ion beam-induced secondary ion mass spectrometry (EDI/SIMS). Positively- and negatively-charged secondary ions were measured for the cancerous and noncancerous regions of the tissue samples. Although specific cancerous species could not be found in both the positive and negative secondary ion spectra, the spectra of the cancerous and noncancerous tissues presented different trends. For instance, in the m/z range of 500-800 of the positive secondary ion spectra for the cancerous tissues, the intensities for several m/z values were lower than those of the m/z+2 peaks (indicating one double bond loss for the species), whereas, for the noncancerous tissues, the inverse trend was obtained...
2017: Mass Spectrometry
Yuki Yamada, Satoshi Ninomiya, Kenzo Hiraoka, Lee Chuin Chen
We report on combining a self-aspirated sampling probe and an ESI source using a single metal capillary which is electrically grounded and safe for use by the operator. To generate an electrospray, a negative H.V. is applied to the counter electrode of the ESI emitter to operate in positive ion mode. The sampling/ESI capillary is enclosed within another concentric capillary similar to the arrangement for a standard pneumatically assisted ESI source. The suction of the liquid sample is due to the Venturi effect created by the high-velocity gas flow near the ESI tip...
2016: Mass Spectrometry
Natsuhiko Sato, Kanako Sekimoto, Mitsuo Takayama
Atmospheric pressure corona discharge (APCD) was applied to the ionization of volatile organic compounds. The mass spectra of analytes having aromatic, phenolic, anilinic, basic and aliphatic in nature were obtained by using vapor supply and liquid smear supply methods. The vapor supply method mainly gave protonated analytes [A+H](+) caused by proton transfer from hydronium ion H3O(+), except for benzene, toluene and n-hexane that have lower proton affinity. The use of the liquid smear supply method resulted in the formation of molecular ion A(·+) and/or dehydride analyte [A-H](+), according to the nature of analytes used...
2016: Mass Spectrometry
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