TY - JOUR. T1 - The characterisation of coumarins from selected structural classes by electrospray ionisation quadrupole time-of-flight tandem mass spectrometry. AU - Smyth, Franklin. AU - Morgan, Jason L.. AU - OKane, Edmund. AU - Millar, Tommy J.. AU - Ramachandran, Venkataraman N.. PY - 2011/5. Y1 - 2011/5. N2 - Electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) has been used for characterisation of a selection of naturally occurring and synthetic coumarins from different structural classes. The product ions, suggested in earlier studies by electrospray ionisation ion trap mass spectrometry (ESI-MSn), are unequivocally established for the representative coumarins by virtue of accurate mass measurement. Synthetic coumarins that are unsubstituted in the heterocyclic ring give rise to a major product ion by loss of CO2, whereas those substituted in the heterocyclic ring generally undergo alternative fragmentation releasing neutral species such as ketene ...
TY - JOUR. T1 - Development of liquid chromatography electrospray ionization tandem mass spectrometry methods for analysis of DNA adducts of formaldehyde and their application to rats treated with N-nitrosodimethylamine or 4-(methylnitrosamino) -1-(3-pyridyl)-1-butanone. AU - Wang, Mingyao. AU - Cheng, Guang. AU - Villalta, Peter W. AU - Hecht, Stephen S. PY - 2007/8. Y1 - 2007/8. N2 - Reaction of formaldehyde with DNA in vitro produces a variety of adducts among which are observed the cross-link di-(N6-deoxyadenosyl)methane (dAdo-CH2-dAdo, 1) and the hydroxymethyl adduct N6- hydroxymethyl-dAdo (N6-HOCH2-dAdo, 2). While the structures of these adducts have been known for decades, there have been no reports of their formation in vivo. Formaldehyde is released during intracellular metabolism of carcinogenic N-nitrosomethyl compounds such as N-nitrosodimethylamine (NDMA) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), but DNA adducts formed by this pathway have not been previously ...
Biological fluids such as urine, saliva and whole blood were analyzed for contents of drugs by a new combination of desorption electrospray ionization mass spectrometry (DESI-MS) and thin liquid membrane extraction (TLME). Analytes from the sample were extracted into a thin liquid membrane of hexadecane deposited on a porous Teflon membrane, from which they were subsequently analyzed directly by DESI. The total analysis time was 15 minutes for analysis of several samples with a potential analysis time of less than a minute per sample. Thanks to the pre-concentration and sample clean-up built into the method, methadone was detected in urine in full-scan mode with an LOD of 4 ng mL(-1), while amitriptyline, nortriptyline and pethidine showed LODs of 17 ng mL(-1). Quantification was possible for several basic drugs using one common internal standard, providing relative accuracies in the range of 10-30%. A reliability test was performed on 20 samples with methadone, amitriptyline, nortriptyline and ...
TY - JOUR. T1 - Flavor release measurement by atmospheric pressure chemical ionization ion trap mass spectrometry, construction of interface and mathematical modeling of release profiles. AU - Haahr, Anne-Mette. AU - Madsen, Henrik. AU - Smedsgaard, Jørn. AU - Bredie, W.L.P.. AU - Stahnke, Louise Heller. AU - Refsgaard, Hanne. PY - 2003. Y1 - 2003. N2 - An instrumental on-line retronasal flavor analysis was developed to obtain information about the release of flavor compounds in expired air from humans during eating. The volatile flavor compounds were measured by ion trap mass spectrometry with an atmospheric pressure chemical ionization source (APCI). An interface was designed to sample the breath directly from the nose. The repeat-ability in vitro for seven different flavor compounds came out with relative standard derivation less than 10% in most cases, which is acceptable. In vitro quantification was carried out by a determination of the concentration in the gas phase over a flavor solution ...
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TY - JOUR. T1 - Optimized extraction of phospholipids and lysophospholipids for nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry. AU - Byeon, Seul Kee. AU - Lee, Ju Yong. AU - Moon, Myeong Hee. PY - 2012/1/21. Y1 - 2012/1/21. N2 - The efficiencies of four different methods for the extraction of phospholipids (PLs) and lysophospholipids (LPLs) from human plasma samples were examined by comparing extraction recovery values using nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nLC-ESI-MS). For recovery measurements, six PL and six LPL standards of different head groups were spiked into a human plasma sample, and the peak areas of each individual species after extraction were measured from the chromatograms of the nLC-ESI-MS runs. Recovery was calculated by comparing the peak area of an extracted standard species with that of the same species spike after extraction of the same plasma sample. For lipid extraction, four different extraction ...
A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine and its principal metabolites cotinine, trans-3-hydroxycotinine and cotinine-N-oxide, caffeine and arecoline in breast milk, using N-ethylnorcotinine as internal standard. Li …
TY - JOUR. T1 - Fast Quantitative Detection of Cocaine in Beverages Using Nanoextractive Electrospray Ionization Tandem Mass Spectrometry. AU - Hu, Bin. AU - Peng, Xuejiao. AU - Yang, Shuiping. AU - Gu, Haiwei. AU - Chen, Huanwen. AU - Huan, Yanfu. AU - Zhang, Tingting. AU - Qiao, Xiaolin. PY - 2010/2/1. Y1 - 2010/2/1. N2 - Without any sample pretreatment, effervescent beverage fluids were manually sprayed into the primary ion plume created by using a nanoelectrospray ionization source for direct ionization, and the analyte ions of interest were guided into an ion trap mass spectrometer for tandem mass analysis. Functional ingredients (e.g., vitamins, taurine, and caffeine, etc.) and spiked impurity (e.g., cocaine) in various beverages, such as Red Bull energy drink, Coco-cola, and Pepsi samples were rapidly identified within 1.5 s. The limit of detection was found to be 7 ∼ 15 fg (S/N = 3) for cocaine in different samples using the characteristic fragment (m/z 150) observed in the MS3 ...
In Mays featured publication, Dr. Agar and colleagues developed tools using mass spectrometry to be used to characterize meningioma tumor from healthy brain tissue during surgery. These tools could therefore enable surgeons to detect the borders of the tumor better, and remove only the tumor tissue, leaving the healthy brain tissue behind. These developments could be extended to other brain tumor types in the future, improving surgical procedures.. ...
TY - JOUR. T1 - Screening of Threading Bis-Intercalators Binding to Duplex DNA by Electrospray Ionization Tandem Mass Spectrometry. AU - Mazzitelli, Carolyn L.. AU - Chu, Yongjun. AU - Reczek, Joseph J.. AU - Iverson, Brent L.. AU - Brodbelt, Jennifer S.. PY - 2007/2/1. Y1 - 2007/2/1. N2 - The DNA binding of novel threading bis-intercalators V1, trans-D1, and cis-C1, which contain two naphthalene diimide (NDI) intercalation units connected by a scaffold, was evaluated using electrospray ionization mass spectrometry (ESI-MS) and DNAse footprinting techniques. ESI-MS experiments confirmed that V1, the ligand containing the -Gly3-Lys- peptide scaffold, binds to a DNA duplex containing the 5′-GGTACC-3′ specific binding site identified in previous NMR-based studies. The ligand formed complexes with a ligand/DNA binding stoichiometry of 1:1, even when there was excess ligand in solution. Trans-D1 and cis-C1 are new ligands containing a rigid spiro-tricyclic scaffold in the trans- and cis- ...
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TY - JOUR. T1 - Screening and classifying small-molecule inhibitors of amyloid formation using ion mobility spectrometry-mass spectrometry. AU - Young, Lydia M.. AU - Saunders, Janet C.. AU - Mahood, Rachel A.. AU - Revill, Charlotte H.. AU - Foster, Richard J.. AU - Tu, Ling Hsien. AU - Raleigh, Daniel P.. AU - Radford, Sheena E.. AU - Ashcroft, Alison E.. PY - 2015/1/1. Y1 - 2015/1/1. N2 - The search for therapeutic agents that bind specifically to precursor protein conformations and inhibit amyloid assembly is an important challenge. Identifying such inhibitors is difficult because many protein precursors of aggregation are partially folded or intrinsically disordered, which rules out structure-based design. Furthermore, inhibitors can act by a variety of mechanisms, including specific or nonspecific binding, as well as colloidal inhibition. Here we report a high-throughput method based on ion mobility spectrometry-mass spectrometry (IMS-MS) that is capable of rapidly detecting small ...
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TY - JOUR. T1 - Identification of glyceollin metabolites derived from conjugation with glutathione and glucuronic acid in male ZDSD rats by online liquid chromatography-electrospray ionization tandem mass spectrometry. AU - Quadri, Syeda S.. AU - Stratford Jr., Robert. AU - Boué, Stephen M.. AU - Cole, Richard B.. PY - 2014/3/26. Y1 - 2014/3/26. N2 - Glyceollin-related metabolites produced in rats following oral glyceollin administration were screened in plasma, feces, and urine, and these metabolites were identified by precursor and product ion scanning using liquid chromatography coupled online with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Precursor ion scanning in the negative ion (NI) mode was used to identify all glyceollin metabolites based on production of a diagnostic radical product ion (m/z 148) upon decomposition. Using this approach, precursor peaks of interest were found at m/z 474 and 531. Tandem mass spectra of these two peaks allowed us to characterize ...
Carbamazepine (CBZ) and oxcarbazepine (OXCBZ) are both antiepileptic drugs, which are prescribed as first-line drugs for the treatment of partial and generalized tonic-clonic epileptic seizures. In this paper, a specific and sensitive liquid chromatography-electrospray ionization mass spectrometry m …
We have demonstrated an on-line laser ablation sampling system and coupling of the system to liquid chromatography (LC) using an infrared (IR) laser to ablate and transfer materials into a flowing solvent stream. With this approach, samples are depos
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
DNA adduct formation of the aromatic amine, 4-aminobiphenyl (4-ABP), a known human carcinogen present in tobacco smoke, and the heterocyclic aromatic amines (HAAs), 2-amino-9H-pyrido[2,3-b]indole (AαC), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), potential human carcinogens, which are also present in tobacco smoke or formed during the high-temperature cooking of meats, was investigated in freshly cultured human hepatocytes. The carcinogens (10 μM) were incubated with hepatocytes derived from eight different donors for time periods up to 24 h. The DNA adducts were quantified by liquid chromatography-electrospray ionization mass spectrometry with a linear quadrupole ion trap mass spectrometer. The principal DNA adducts formed for all of the carcinogens were N-(deoxyguanosin-8-yl) (dG-C8) adducts. The levels of adducts ranged from 3.4 to 140 adducts per 10(7) DNA bases. The highest level of
A reversed-phase high-performance liquid chromatographic (HPLC) method is applied for the determination of galacturonic acid (GA) of pectins in different commercial fruit juices. The separation was carried out on a C18 column using precolumn derivatization with p-aminobenzoic acid (p-ABA) and UV detection at 304 nm. The identification of GA was confirmed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) in positive ion mode. The concentration of GA in the samples analyzed ranged from 12.9 ± 0.5 to 49.4 ± 0.5 mgGA L−1. Amongst the samples analyzed, mango juice was found to be richest in GA content, and therefore a good source of pectins. Detection and quantification limits of the described methodology were 1.2 and 3.9 mg L−1, respectively. Quantitative GA recoveries in the beverages had a range between 90 and 98%. The results showed that the HPLC method proposed was precise and suitable for the identification and quantification of GA ...
A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in plasma and saliva samples utilizing liquid chromatography-electrospray ionization tandem mass spectrometry was developed and validated. Human plasma and saliva samples were pretreated by microextraction by packed sorbent (MEPS) prior to analysis. A new MEPS syringe form with two inputs was used. Metoprolol enantiomers and internal standard pentycaine (IS) were eluted from MEPS sorbent using isopropanol after removal of matrix interferences using aliquots of 5% methanol in water. Complete separation of metoprolol enantiomers was achieved on a Cellulose-SB column (150 × 4.6 mm, 5 μm) using isocratic elution with mobile phase 0.1% ammonium hydroxide in hexane-isopropanol (80:20, v/v) with a flow rate of 0.8 mL/min. A post-column solvent-assisted ionization was applied to enhance metoprolol ionization signal in positive mode monitoring (+ES) using 0.5% formic acid in isopropanol at a ...
Parkinsons disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal pathway, where patients do not manifest motor symptoms until ,50% of neurons are lost. Thus, it is of great importance to determine early neuronal changes that may contribute to disease progression. Recent attention has focused on lipids and their role in pro- and anti-apoptotic processes. However, information regarding the lipid alterations in animal models of PD is lacking. In this study, we utilized high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) and novel HPLC solvent methodology to profile phosphatidylcholines and sphingolipids within the substantia nigra. The ipsilateral substantia nigra pars compacta was collected from rats 21 days after an infusion of 6-hydroxydopamine (6-OHDA), or vehicle into the anterior dorsal striatum. We identified 115 lipid species from their mass/charge ratio using the LMAPS Lipid MS Predict Database. Of these, ...
The gold standard for cystic fibrosis (CF) diagnosis is the determination of chloride concentration in sweat. Current testing methodology takes up to 3 h to complete and has recognized shortcomings on its diagnostic accuracy. We present an alternative method for the identification of CF by combining desorption electrospray ionization mass spectrometry and a machine-learning algorithm based on gradient boosted decision trees to analyze perspiration samples. This process takes as little as 2 min, and we determined its accuracy to be 98 ± 2% by cross-validation on analyzing 277 perspiration samples. With the introduction of statistical bootstrap, our method can provide a confidence estimate of our prediction, which helps diagnosis decision-making. We also identified important peaks by the feature selection algorithm and assigned the chemical structure of the metabolites by high-resolution and/or tandem mass spectrometry. We inspected the correlation between mild and severe CFTR gene mutation types ...
Altered metabolism is an inherent property of cancer and provides a rich opportunity for exploring its underlying biology and developing diagnostic biomarkers. We used desorption electrospray ionization mass spectrometry ...
Os tumores bif sicos da mama formam um grupo heterog neo de tumores que apresentam na histologia dois componentes, o epitelial e o estromal. Esses tumores podem ser benignos ou malignos, alguns podem recidivar ou dar met stase. O seu progn stico varia conforme a sua classifica o histol gica, a presen a de met stase e a adequabilidade do seu tratamento. Por m, por vezes, h ainda dificuldade em diferenci -los quando h sobreposi o das caracter sticas histol gicas que s o utilizadas para realizar o diagn stico no exame anatomopatol gico. Visando um novo m todo para diferenciar esses tumores entre si, al m do exame anatomopatol gico habitual, buscou-se analisar esses tumores atrav s de uma t cnica da qu mica anal tica de ioniza o ambiente, utilizando espectrometria de massas, o DESI-MSI (Desorption Electrospray Ionization Mass Spectrometry Imaging). Foram utilizados cortes de amostras congeladas em l minas para analisar no DESI-MSI e, atrav s dessa an lise, obteve-se os espectros de massas e as ...
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TY - JOUR. T1 - Identification of ethyl pyruvate and dihydrocinchonidine adducts by electrospray ionization mass spectrometry. AU - Bartók, Mihály. AU - Szabó, Pál Tamás. AU - Bartók, Tibor. AU - Szöllösi, György. PY - 2000/1/1. Y1 - 2000/1/1. N2 - Several ethyl pyruvate and dihydrocinchonidine adducts, formed by non-covalent interactions with alkali cations, have been identified for the first time using electrospray ionization mass and tandem mass spectrometry. This type of adduct may have an important role in asymmetric reactions of pyruvates in the presence of cinchonas. Copyright (C) 2000 John Wiley and Sons, Ltd.. AB - Several ethyl pyruvate and dihydrocinchonidine adducts, formed by non-covalent interactions with alkali cations, have been identified for the first time using electrospray ionization mass and tandem mass spectrometry. This type of adduct may have an important role in asymmetric reactions of pyruvates in the presence of cinchonas. Copyright (C) 2000 John Wiley and ...
Bisphenol A (BPA) is a weak estrogen. Pharmacokinetic studies of BPA have demonstrated a rapid and extensive metabolism of BPA to the nonestrogenic BPA-monoglucuronide (BPA-gluc). Some investigators have reported that BPA was found at parts per billion concentrations in the tissues or urine of humans without known exposure to BPA. This work developed a rapid and sensitive method for the determination of BPA and BPA-gluc in plasma and urine based on liquid chromatography-tandem mass spectrometry. The liquid chromatography-electrospray ionization-tandem mass spectrometry method for quantitation of BPA and BPA-gluc uses stable isotope-labeled internal standards. A linear ion trap mass spectrometer permits identification and quantitation of BPA-gluc and BPA without sample workup. Development of separation conditions reduced the BPA-background in solvent samples to below 2.5 pmol/ml for BPA. Limit of quantitation (LOQ) for BPA in control urine was 15 pmol/ml; LOQ for BPA-gluc was 65 pmol/ml. ...
This thesis presents three different series of high energy (keV) collision experiments as well as a brief scientific introduction to the field. In the first series, protonated glycine and leucine were collided with carbon dioxide and a beam attenuation method was applied to determine their total fragmentation cross sections. A technique was also presented for how to restore the resolution in mass spectra obtained with a hemispherical electrostatic analyzer followed by a position sensitive detector (micro-channel plate equipped with a resistive anode). In the second series of experiments, Collision Induced Dissociation (CID) and Electron Capture Induced Dissociation (ECID) studies were performed on the nucleotide adenosine 5-monophosphate anion (AMP-) in water complexes. The two dissociation techniques revealed different fragmentation patterns and a numerical solvent evaporation model was used to interpret the spectra. It was then found that the CID and ECID processes were associated with ...
TY - JOUR. T1 - Probing conformational changes of ubiquitin by host-guest chemistry using electrospray ionization mass spectrometry. AU - Lee, Jong Wha. AU - Heo, Sung Woo. AU - Lee, Shin Jung C.. AU - Ko, Jae Yoon. AU - Kim, Hyungjun. AU - Kim, Hugh I.. PY - 2013/1/1. Y1 - 2013/1/1. N2 - We report mechanistic studies of structural changes of ubiquitin (Ub) by host-guest chemistry with cucurbit[6]uril (CB[6]) using electrospray ionization mass spectrometry (ESI-MS) combined with circular dichroism spectroscopy and molecular dynamics (MD) simulation. CB[6] binds selectively to lysine (Lys) residues of proteins. Low energy collision-induced dissociation (CID) of the protein-CB[6] complex reveals CB[6] binding sites. We previously reported (Anal. Chem. 2011, 83, 7916-7923) shifts in major charge states along with Ub-CB[6] complexes in the ESI-MS spectrum with addition of CB[6] to Ub from water. We also reported that CB[6] is present only at Lys6 or Lys11 in high charge state (+13) complex. In this ...
Negative electrospray ionization mass spectrometry of synthetic and chemically modified oligonucleotides.: We report here on the analysis of synthetic oligonucl
We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography-electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple dilute and shoot sample preparation. The quantification is conducted b ...
We report here a simple and rapid method for the quantification of brominated vegetable oil (BVO) in soft drinks based upon liquid chromatography-electrospray ionization mass spectrometry. Unlike previously reported methods, this novel method does not require hydrolysis, extraction or derivatization steps, but rather a simple dilute and shoot sample preparation. The quantification is conducted b ...
Author: Göth, Melanie et al.; Genre: Thesis; Keywords: native mass spectrometry; ion mobility; protein complexes; Title: Investigation of Protein-Ligand Complexes by Native Mass Spectrometry and Ion Mobility-Mass Spectrometry
A precise HPLC/MS/MS approach; Lipidomics in Diabetes and the Metabolic Syndrome; LC-MS-MS research of impartial Eicosanoids; Quantification Of F2-Isoprostanes In organic Fluids And Tissues As A degree Of Oxidant rigidity; dimension of goods of Docosahexaenoic Acid Peroxidation, Neuroprostanes, and Neurofurans; Enantiomeric separation of hydroxy and hydroperoxy eicosanoids through chiral column chromatography; exact Chiral Lipidomics research by means of Liquid Chromatography Electron seize Atmospheric strain Chemical Ionization Mass Spectrometry (LC-ECAPCI/MS); Shotgun Lipidomics by means of Tandem Mass Spectrometry lower than Data-Dependent Acquisition keep an eye on; id of Intact Lipid Peroxides via Ag+ Coordination Ionspray Mass Spectrometry (CIS-MS); Quantification of Cardiolipin by means of Liquid Chromatography Electrospray Ionization Mass Spectrometry ...
J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Sep 15;857(1):1-8. Epub 2007 Jun 29. Comparative Study; Evaluation Studies; Research Support, N.I.H., Extramural
Soybean seeds are an important source of vegetable oil and biomaterials. The content of individual triacylglycerol species (TAG) in soybean seeds is difficult to quantify in an accurate and rapid way. The present study establishes an approach to quantify TAG species in soybean seeds utilizing an electrospray ionization tandem mass spectrometry with multiple neutral loss scans. Ten neutral loss scans were performed to detect the fatty acyl chains of TAG, including palmitic (P, 1650), linolenic (Ln, 1853), linoleic (L, 1852), oleic (O, 1851), stearic (S, 1850), eicosadienoic (2052), gadoleic (2051), arachidic (2050), erucic (2251), and behenic (2250). The abundance of ten fatty acyl chains at 46 TAG masses (mass-to-charge ratio, m/z) were determined after isotopic deconvolution and correction by adjustment factors at each TAG mass. The direct sample infusion and multiple internal standards correction allowed a rapid and accurate quantification of TAG species. Ninety-three TAG species were resolved ...
Title:Effect of Electrospray Ionization Source Parameters on Pharmaceuticals Analysis Using Quadrupole Time-of-Flight Mass Spectrometry. VOLUME: 12 ISSUE: 4. Author(s):Ummi N.S.B. Masseren, Soo W. Khor, Kheng S. Tay* and Mhd R.B. Abas*. Affiliation:Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia.. Keywords:Environmental analysis, HPLC, organic pollutants, ESI, MS, pharmaceuticals and personal care products.. Abstract:. Introduction: The presence of pharmaceuticals in the environment has caused increasing concern. In the development of analytical method, selection of sensitive analytical instrument is also an important consideration. Among various analytical instruments, HPLC coupled with ESI based QTOF high resolution MS has recently emerged as a powerful analytical tool for the analysis of trace pharmaceuticals in environmental waters. This study evaluated the influence of ESI source parameters which include capillary voltage, nozzle voltage, ...
Phosphatidylethanolamines (PEs) are one of the major constituents of cellular membranes, and, along with other phospholipid classes, have an essential role in the physiology of cells. Profiling of phospholipids in biological samples is currently done using mass spectrometry (MS). In this work we describe the MS fragmentation of sodium adducts of 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphatidylethanolamine (POPE) and 2-linoleoyl-1-palmitoyl-sn-glycero-3-phosphatidylethanolamine (PLPE). This study was performed by electrospray ionization tandem mass spectrometry (ESI-MS/MS) using three different instruments and also by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). All MS/MS spectra show product ions related to the polar head fragmentation and product ions related to the loss of acyl chains. In ESI-MS/MS spectra, the product ions [M+Na-R1COOH-43]+ and [M+Na-R2COOH-43]+ show different relative abundance, as well as [M+Na-R1COOH]+ and [M+Na-R2COOH]+ product ions, ...
Unfixed tissue specimens most frequently are stored for long term research uses at either -80° C or in vapor phase liquid nitrogen (VPLN). There is little information concerning the effects such long term storage on tissue RNA or protein available for extraction. Aliquots of 49 specimens were stored for 5-12 years at -80° C or in VPLN. Twelve additional paired specimens were stored for 1 year under identical conditions. RNA was isolated from all tissues and assessed for RNA yield, total RNA integrity and mRNA integrity. Protein stability was analyzed by surface-enhanced or matrix-assisted laser desorption ionization time of flight mass spectrometry (SELDI-TOF-MS, MALDI-TOF-MS) and nano-liquid chromatography electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS). RNA yield and total RNA integrity showed significantly better results for -80° C storage compared to VPLN storage; the transcripts that were preferentially degraded during VPLN storage were these involved in antigen ...
BACKGROUND: Low-dose methotrexate (MTX) is the first-line therapy in early rheumatoid arthritis (eRA). Up to 40% of eRA patients do not benefit from MTX therapy. MTX has been shown to inhibit one-carbon metabolism, which is involved in the donation of methyl groups. In this study, we investigate baseline global DNA methylation and changes in DNA methylation during treatment in relation to clinical non-response after 3 months of MTX treatment. METHODS: Two hundred ninety-four blood samples were collected from the Treatment in the Rotterdam Early Arthritis Cohort (tREACH, ISRCTN26791028), a multicenter, stratified single-blind clinical trial of eRA patients. Global DNA (hydroxy)methylation was quantified using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) and validated with a global DNA LINE-1 methylation technique. MTX response was determined as ΔDAS28. Additionally, patients were stratified into two response groups according to the European League Against ...
A new platinum(II) complex with methionine sulfoxide was synthesized and characterized by chemical and spectroscopic techniques. Elemental analyses, mass spectrometric measurements (electrospray ionization quadrupole time-of-flight mass spectrometry), and thermal analyses of the solid compound fit the composition [(C5H10NO3S)Pt(mu-Cl)(2)Pt(C5H10NO3S)]center dot 2.5H(2)O. Infrared spectroscopic data indicate coordination of the ligand to Pt(II) through the nitrogen of NH2 and the sulfur of the S=O group. H-1-N-15 nuclear magnetic resonance spectroscopic data confirm nitrogen coordination. Antibacterial activities were evaluated by antibiogram assays using the disc diffusion method. The platinum(II) complex showed antibacterial activity against Gram-negative Pseudomonas aeruginosa bacterial cells ...
TY - JOUR. T1 - A combination of molecular probe-tandem electrospray ionization mass spectrometry. T2 - A technique for tracing structural changes in phospholipid hydroperoxides. AU - Shimizu, Rumiko. AU - Nagai, Ai. AU - Tominaga, Hiroko. AU - Imura, Megumi. AU - Onyango, Arnold N.. AU - Izumi, Minoru. AU - Nakajima, Shuhei. AU - Tahara, Shoichi. AU - Kaneko, Takao. AU - Baba, Naomichi. PY - 2009. Y1 - 2009. N2 - An ethyl-labeled phosphatidylcholine hydroperoxide (PC-OOH/Et 2) was synthesized as a molecular probe for naturally occurring PC-OOH 1. Applying the precursor ion scan mode in tandem ESI mass spectrometry at m/z 198, a signal of the PC-OOH/Et 2 alone could be selectively detected even in the presence of a large excess of a complex mixture of phospholipids in the blood. Furthermore, molecular species that formed from PC-OOH/Et 2 by its degradation in the blood were also observed in the same spectrum. Since the molecular probe-and-mass spectrometry-assisted analytical method presented ...
Native nanoelectrospray ionization mass spectrometry is an underutilized technique for fragment screening. In this study, the first demonstration is provided of the use of native mass spectrometry for screening fragments against a protein-DNA interaction. EthR is a transcriptional repressor of EthA expression in Mycobacterium tuberculosis (Mtb) that reduces the efficacy of ethionamide, a second‐line antitubercular drug used to combat multidrug‐resistant Mtb strains. A small‐scale fragment screening campaign was conducted against the EthR-DNA interaction using native mass spectrometry, and the results were compared with those from differential scanning fluorimetry, a commonly used primary screening technique. Hits were validated by surface plasmon resonance and X‐ray crystallography. The screening campaign identified two new fragments that disrupt the EthR-DNA interaction in vitro (IC50=460-610 μm) and bind to the hydrophobic channel of the EthR dimer ...
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Allium hookeri (AH) is widely consumed as a vegetable and herbal medicine in southeastern Asia. AH has been reported antioxidant, antimicrobial, improvement of bone health and antidiabetic effects. In the present study, we investigated the inhibitory effect of a methanol extract of AH root (AHE) on inflammatory response in lipopolysaccharide (LPS)-induced RAW264.7 cells. Initially, characterization of organic sulfur compounds in AHE was determined using high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Cells were incubated with LPS and AHE for 24 h. The productions of nitric oxide (NO), reactive oxygen species (ROS), and inflammation-related cytokines were examined. Gene and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were assessed by polymerase chain reaction and Western blotting. Key factor, nuclear factor kappa B (NF-κB) was also determined. AHE contained organosulfur compounds
Allium hookeri (AH) is widely consumed as a vegetable and herbal medicine in southeastern Asia. AH has been reported antioxidant, antimicrobial, improvement of bone health and antidiabetic effects. In the present study, we investigated the inhibitory effect of a methanol extract of AH root (AHE) on inflammatory response in lipopolysaccharide (LPS)-induced RAW264.7 cells. Initially, characterization of organic sulfur compounds in AHE was determined using high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Cells were incubated with LPS and AHE for 24 h. The productions of nitric oxide (NO), reactive oxygen species (ROS), and inflammation-related cytokines were examined. Gene and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were assessed by polymerase chain reaction and Western blotting. Key factor, nuclear factor kappa B (NF-κB) was also determined. AHE contained organosulfur compounds
DNA methylation is an epigenetic mechanism regulating gene expression that has been insufficiently studied in the blood of rheumatoid arthritis (RA) patients, as only T cells and total peripheral blood mononuclear cells (PBMCs) from patients with established RA have been studied and with conflicting results. Five major blood cell subpopulations: T, B and NK cells, monocytes, and polymorphonuclear leukocytes, were isolated from 19 early RA patients and 17 healthy controls. Patient samples were taken before and 1 month after the start of treatment with methotrexate (MTX). Analysis included DNA methylation with high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry-selected reaction monitoring (HPLC-ESI-MS/MS-SRM) and expression levels of seven methylation-specific enzymes by quantitative polymerase chain reaction (qPCR). Disease-modifying anti-rheumatic drug (DMARD)-naïve early RA patients showed global DNA hypomethylation in T cells and monocytes, together with a lower
Rapid analysis of anabolic steroid metabolites in urine by combining field asymmetric waveform ion mobility spectrometry with liquid chromatography and mass spectrometry
OBJECTIVE To study alkaloids of Senecio scandens growing in Guangdong. METHODS The rapid resolution liquid chromatography-electrospray ionization mass spectrometry (RRLC-ESI-MS/MS) was used to analyse alkaloids of Senecio scandens growing in Guangdong, and senkirkine was isolated and purified by silica gel column chromatography. RESULTS Four alkaloids were identified as senkirkine, dehydrosenkirkine, monocrotaline and adonifoline, and senkirkine was firstly isolated from Senecio scandens growing in Guangdong. CONCLUSION Senkirkine is the main component of Senecio scandens growing in Guangdong.
Feijoa fruit is becoming increasingly popular, yet limited studies have focused on the antioxidant capacity and phenolic profiling of its extracts. In this research, optimization of phenolic extraction from feijoa flesh, peel, and whole fruit from four New Zealand grown cultivars was conducted using orthogonal design. Antioxidant activities of the extracts were assessed, followed by phenolic profiling by a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. For feijoa flesh and whole fruit, the extraction was optimized using 70% ethanol, material to solvent ratio of 1:30, at extraction temperature of 50 °C for 30 min. For feijoa peel, extraction at 50 °C for 60 min using 50% ethanol with a material to solvent ratio of 1:30 were the optimized conditions. Results showed feijoa peel had higher total phenolic content (TPC) and antioxidant activities than the flesh and whole fruit. Overall, the Unique cultivar had a relatively higher TPC and ...
Fibrates, such as fenofibrate, are peroxisome proliferator-activated receptor-α (PPARα) agonists and have been used for several decades as hypolipidemic agents in the clinic. However, contradictory observations exist on the role of fibrates in host response to acute inflammation, with unclear mechanisms. The role of PPARα in colitis was assessed using fenofibrate and Ppara-null mice. Wild-type or Ppara-null mice were subjected to acute colitis under three distinct protocols, dextran sulfate sodium, trinitrobenzenesulfonic acid, and Salmonella Typhi. Serum and colon lipidomics were analyzed to characterize the metabolic profiles by ultra-performance liquid chromatography-coupled with electrospray ionization quadrupole time-of-flight mass spectrometry. Messenger RNAs of PPARα target genes and genes involved in inflammation were determined by qunatitative PCR analysis. Fenofibrate treatment exacerbated inflammation and tissue injury in acute colitis, and this was dependent on PPARα activation.
Anthocyanins are naturally occurring polyphenols that impart bright color to fruits, vegetables and plants. In this study, the extraction of anthocyanins from freeze-dried fruit skin of downy rose-myrtle (Rhodomyrtus tomentosa (Ait.) Hassk var. Gangren) was optimized using response surface methodology (RSM). Using 60% ethanol containing 0.1% (v/v) hydrochloric acid as extraction solvent, the optimal conditions for maximum yields of anthocyanin (4.358 ± 0.045 mg/g) were 15.7:1 (v/w) liquid to solid ratio, 64.38 °C with a 116.88 min extraction time. The results showed good fits with the proposed model for the anthocyanin extraction (R2 = 0.9944). Furthermore, the results of high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) analysis of the anthocyanins extracted from the fruit skin of downy rose-myrtle revealed the presence of five anthocyanin components, which were tentatively identified as delphinidin-3-glucoside, cyanidin-3-glucoside, peonidin-3-glucoside,
TY - JOUR. T1 - Proteomic analysis of pathogenic and attenuated alcelaphine herpesvirus 1. AU - Dry, Inga. AU - Haig, David M. AU - Inglis, Neil F. AU - Imrie, Lisa. AU - Stewart, James P.. AU - Russell, George C. PY - 2008/6. Y1 - 2008/6. N2 - The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparations were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and proteins were analyzed by liquid chromatography-electrospray ionization-tandem mass spectrometry. Peptides were identified in serial gel slices by using MASCOT software to ...
Looking for online definition of electrospray ionisation in the Medical Dictionary? electrospray ionisation explanation free. What is electrospray ionisation? Meaning of electrospray ionisation medical term. What does electrospray ionisation mean?
Polar components in fuels may enable differentiation between fuel types or commercial fuel sources. A range of commercial fuels from numerous sources were analyzed by flow injection analysis/electrospray ionization/mass spectrometry without extensive sample preparation, separation, or chromatography. This technique enabled screening for unique polar components at parts per million levels in commercial hydrocarbon products, including a range of products from a variety of commercial sources and locations. Because these polar compounds are unique in different fuels, their presence may provide source information on hydrocarbons released into the environment. This analysis was then applied to mixtures of various products, as might be found in accidental releases into the environment. Copyright ?? Taylor & Francis Group, LLC....
TY - JOUR. T1 - Matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight (MALDI-QIT-TOF)-based imaging mass spectrometry reveals a layered distribution of phospholipid molecular species in the mouse retina. AU - Hayasaka, Takahiro. AU - Goto-Inoue, Naoko. AU - Sugiura, Yuki. AU - Zaima, Nobuhiro. AU - Nakanishi, Hiroki. AU - Ohishi, Kentaro. AU - Nakanishi, Setsuko. AU - Naito, Takayuki. AU - Taguchi, Ryo. AU - Setou, Mitsutoshi. PY - 2008/11/15. Y1 - 2008/11/15. N2 - We recently developed a matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight (MALDI-QIT-TOF)-based imaging mass spectrometry (IMS) system. This system enables us to perform structural analyses using tandem mass spectrometry (MS/MS), as well as to visualize phospholipids and peptides in frozen sections. In the retina, phototransduction is regulated by the light-sensitive interaction between visual pigment-coupled receptor proteins, such as rhodopsin, and G proteins, such as transducin. ...
The gas-phase acidities and proton affinities of analogs of protein amino acids were investigated. The gas-phase acidities of the lysine homologues were measured by the extended kinetic method in a quadrupole ion trap mass spectrometer. Deprotonation entropy changes were also measured. For ornithine, 2,4-diaminobutyric acid, and 2,3-diaminopropionic acid, the gas-phase acidities measured were 1416 ± 17 kJ/mol, 1420 ± 8 kJ/mol, and 1405 ± 24 kJ/mol. Their changes in entropy were measured to be -19 J/mol K, 1 J/mol k, and -24 J/mol K, respectively. The gas-phase acidities and entropies of two structural analogs of arginine, citrulline and canavanine, were measured by the extended kinetic method. The gas-phase acidity of citrulline was measured to be 1366 ± 11 kJ/mol, and the gas-phase acidity of canavanine was measured to be 1401 ± 13 kJ/mol. The proton affinity and protonation entropy change for citrulline was measured as well. The proton affinity was determined to be 984 ± 11 kJ/mol with an
Structure analysis of partially depolymerized methyl cellulose was performed by nanoelectrospray ionization tandem mass spectrometry (nano-ESI-MS/MS) and by matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS). Dimethylamine (DMA) was used for the first time as a reducing end derivatization reagent for oligosaccharides. This is an attractive reagent since it could be easily removed from the reaction mixture. Most important it also introduces a basic functional group that increased the sensitivity in both MALDI and nano-ESI. Depolymerization was made in two ways: one by the cellulose selective endoglucanase 5A from Bacillus agaradhaerens (Ba Ce15A) and the other by trifluoroacetic acid. The DMA derivatives formed both protonated and sodiated molecules in nano-ESI and MALDI. Tandem MS of protonated molecules yielded predominantly Y fragments from which the distribution of the substituents in the oligomers could be measured. Fragments obtained in tandem MS of sodiated ...
A method for the extraction and quantitation of procaine in equine plasma was developed for use with liquid chromatography-mass spectrometry (LC-MS). Procaine was isolated from equine plasma by liquid-liquid extraction at pH 11 with dichloromethane using procaine-d10 as an internal standard. Quantitation was achieved by LC-MS using a 3-µm C-18 column coupled to an electrospray ionization source on a linear ion-trap mass spectrometer. The limit of detection and limit of quantitation was determined to be 50 and 200 pg/mL, respectively. The lowest limit of detection determined by previous methods was 1 ng/mL. Administration samples were obtained as part of a larger study to determine a regulatory limit for procaine in racehorses and procaine concentrations were determined using this method.. ...
Introduction The fast, precise, and accurate measurement of the new generation of oral anticoagulants such as dabigatran and rivaroxaban in patients plasma my provide important information in different clinical circumstances such as in the case of suspicion of overdose, when patients switch from existing oral anticoagulant, in patients with hepatic or renal impairment, by concomitant use of interaction drugs, or to assess anticoagulant concentration in patients blood before major surgery. Methods Here, we describe a quick and precise method to measure the coagulation inhibitors dabigatran and rivaroxaban using ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry in multiple reactions monitoring (MRM) mode (UPLC-MRM MS). Internal standards (ISs) were added to the sample and after protein precipitation; the sample was separated on a reverse phase column. After ionization of the analytes the ions were detected using electrospray ionization-tandem mass ...
NOTE: Where studies included discovery and validation cohorts, diagnostic metrics of the validation set included for analysis.. Abbreviations: EAC, esophageal adenocarcinoma; ESCC, esophageal squamo-cellular carcinoma; GAC, gastric adenocarcinoma; CRC, colorectal adenocarcinoma; UPLC-TQMS, ultra-performance liquid chromatography-triple quadrupole mass spectrometry; NMR, nuclear magnetic resonance spectroscopy; ESI-TOFMS, electrospray ionization time-of-flight mass spectrometry; RRLC, rapid relaxing liquid chromatography; GC-MS, gas chromatography mass spectrometry; HPLC, high-performance liquid chromatography; FTICR-MS, Fourier transform ion cyclotron mass spectrometry; MS/MS, tandem mass spectrometry; TQMRM, triple quadrupole multiple reaction monitoring; DI, direct ionization; SPME, solid phase microextraction; PLS-DA, partial least squares discriminant analysis; ROC, receiver operating characteristic curve; PCA, principle component analysis; OPLS-DA, orthogonal projection to latent structures ...
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Isoliensinine, a natural phenolic bisbenzyltetrahydroisoquinoline alkaloid, has received considerable attention for its potential biological effects such as antioxidant and anti-HIV activities. From the dog hepatic microsomes of isoliensinine, three new N-demethylated and O-demethylated metabolites, 2-N-desmethyl-isoliensinine (M1), 2-N-desmethylisoliensinine (M2), and 2-N-6-O-didesmethylisoliensinine (M3), were identified by high-performance liquid chromatography and data-dependent electrospray ionization tandem mass spectrometry. Possible metabolic pathways for isoliensinine have been proposed. The result should prove very helpful for evaluation of the drug-like properties of isoliensinine and other bisbenzylisoquinoline alkaloids.
Electrospray mass spectrometry was used to characterize metal-complexing ligands derived from tannic acid, a component of natural dissolved organic matter. Complexes formed by tannin ligands with copper and other biogeochemically important metals were identified from the mass-to-charge ratios of the corresponding deprotonated molecular ions, allowing stoichiometry and metal oxidation state to be determined. Ligand ion intensities were proportional to tannic acid concentration, with detection limits on the order of 5 nM for individual compounds in 50:50 water/acetonitrile. The relative abundance of free ligand and complex ions indicated the degree of complexation under different solution conditions (metal concentration, pH, ionic strength). Using tandem mass spectrometry, the structure and principal copper binding site for one of the tannins were also determined, providing unique information with regard to metal complexation by these polyfunctional ligands. The technique can be combined with high ...
Electrospray mass spectrometry was used to characterize metal-complexing ligands derived from tannic acid, a component of natural dissolved organic matter. Complexes formed by tannin ligands with copper and other biogeochemically important metals were identified from the mass-to-charge ratios of the corresponding deprotonated molecular ions, allowing stoichiometry and metal oxidation state to be determined. Ligand ion intensities were proportional to tannic acid concentration, with detection limits on the order of 5 nM for individual compounds in 50:50 water/acetonitrile. The relative abundance of free ligand and complex ions indicated the degree of complexation under different solution conditions (metal concentration, pH, ionic strength). Using tandem mass spectrometry, the structure and principal copper binding site for one of the tannins were also determined, providing unique information with regard to metal complexation by these polyfunctional ligands. The technique can be combined with high ...
The Global Clinical Mass Spectrometry Market, by product type (GAS Chromatography-Mass Spectrometry, Instrument, Liquid Chromatography-Mass Spectrometry, Instrument, MALDI TOF Mass Spectrometer, Capillary Electrophoresis-Mass Spectrometry, and Ion Mobility Spectrometry-Mass Spectrometry), by application (Clinical Testing, Proteomics, and Drug Discovery), and by end user (Hospitals, Research Laboratories, and Diagnostic Laboratories) was valued at US$ 4,665.3 million in 2016 and is projected to exhibit a CAGR of 7.3% over the forecast period (2017-2025), as highlighted in a new report published by Coherent Market Insights. Focus of key players on development of products through advanced technology and rising prevalence of lifestyle related diseases are attributed to drive meteoric growth of the clinical mass spectrometry market over the forecast period.. Request Sample Copy of the Business Report: https://www.coherentmarketinsights.com/insight/request-sample/193. Clinical mass spectrometry is ...
Simultaneous determination of β-hydroxybutyrate and β-hydroxy-β-methylbutyrate in human whole blood using hydrophilic interaction liquid chromatography electrospray tandem mass ...
G-quadruplexes are nucleic acids structures stabilized by physiological concentration of potassium ions. Because low stability G-quadruplexes are hardly detectable by mass spectrometry, we optimized solvent conditions: isopropanol in a triethylamine/hexafluoroisopropanol mixture highly increased G-quadruplex sensitivity with no modification of the physiological G-quadruplex conformation.
A method was developed and validated for the enantioselective determination of flurbiprofen in rat plasma using liquid chromatography/electrospray ionization-tandem mass spectrometry under reversed-phase elution mode. Two polysaccharide derivatized chiral stationary phases and a homemade β-cyclodextrin (β-CD
Dissociation of peptides induced by interaction with (free) electrons (electron-induced dissociation, EID) at electron energies ranging from near 0 to ,30 eV was carried out using a radio-frequency-free electromagnetostatic (EMS) cell retrofitted into a triple quadrupole mass spectrometer. The product-ion mass spectra exhibited EID originating from electronically excited even electron precursor ions, reduced radical cations formed by capture of low-energy electrons, and oxidized radical cations produced by interaction with high-energy electrons. The spectra demonstrate, within the limits of the triple quadrupoles resolving power, that high-energy EID product-ion spectra produced with an EMS cell exhibit essentially the same qualitative structural information, i.e. amino acid side-chain (SC) losses and backbone cleavages, as observed in high-energy EID spectra produced with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer. The levels of fragmentation efficiency evident in ...
משני יינון electrospray ספקטרומטריית מסה (SESI-MS) מאפשרת זיהוי של תרכובות אורגניות נדיפות (VOCs) ללא צורך המקדים כל המדגם. פרוטוקול זה ...
Positive ion electrospray mass spectrometry (MS) has been used to investigate the interaction of Hg2+, [MeHg]+ and [PhHg]+ cations with cysteine (Cys), glutathione (GSH) and a 27-residue polypeptide (Pp) containing one cysteinyl sulfur located at the N-terminus. MSIMS experiments showed that organomercury adduction occurs primarily at the sulfhydryl group, with some evidence for isomeric species in which the organomercury cation is bound to either an amino or a carboxylic group. Following Ellman modification of GSH and Pp, the maximum number of adducted organomercury cations was reduced by 2 and 1, respectively, indicating a 2:1 and a 1:1 interaction between [RHg]+ and the cysteinyl sulfur. Unlike [PhHg]+, [MeHg]+ showed an almost exclusive affinity for the cysteinyl sulfur of GSH and Pp, Both Cys and GSH reacted with Hg2+ to form polynuclear species. Collisional activation mass spectra of the [2Cys + Hg -H]+ ion indicated that the Hg(II) was most probably bridged between the two cysteinyl ...
You may also wish to search for items by Stone, J. and Stone. 10 matching references were found. Stone, J.A.; Splinter, D.E., A high-pressure mass spectrometric study of the binding of (CH3)3Sn+ to lewis bases in the gas phase, Int. J. Mass Spectrom. Ion Processes, 1984, 59, 169. [all data] Stone, J.A.; Wytenberg, W.J., A high pressure mass spectrometric study of the formation and chemistry of the pentafluorosulphur cation (SF5+), Int. J. Mass Spectrom. Ion Processes, 1989, 94, 269. [all data] Stone, J.A., Binding energies of (CH3)3Si+ to neutrals, Mass Spectrom. Rev., 1997, 16, 25. [all data] Stone, J.M.; Stone, J.A., A high pressure mass spectrometric study of the binding of (CH3)3Si+ and (CH3)3C+ to toluene and benzene, Int. J. Mass Spectrom. Ion Processes, 1991, 109, 247-264. [all data] Zhang, W.; Beglinger, C.; Stone, J.A., High-pressure mass spectrometric study of the gas-phase association of Cl- with alpha,omega-diols, J. Phys. Chem., 1995, 99, 30, 11673, ...
The article evaluated the degradation of the captopril in aqueous solution after ozonation and chlorination. The process was continuously monitored focusing on the identification, mass spectrometry and elucidation of its by-products by applying direct infusion and high performance liquid chromatography, electrospray ionization high resolution mass spectrometry, in the negative ion mode. The cytotoxicity of its by-products solutions were evaluated with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. It was observed through that after 30 min of ozonation and chlorination, there was complete oxidation of captopril, i.e., 100% removal efficiency. At these conditions, the rate of mineralization, by total organic carbon, was only 7.63% for ozonation and 6.40% for chlorination, evidencing the formation of degradation by-products. Ten captopril by-products were identified and their respective chemical structures elucidations are proposed. The treated samples and their by-products
Se fullstendig oversikt over publikasjoner i CRIStin.. Araujo P, Zeng YX, , Du ZY, Ngyuen TT, Frøyland L, Grung B (2010): Discrimination of n-3 Rich Oils by Gas Chromatography, Lipids, 45, 1147-1158. Zeng YX, Araujo P, Du ZY, Ngyuen TT, Frøyland L, Grung B (2010): Elucidation of triacylglycerols in cod liver oil by liquid chromatography electrospray tandem ion-trap mass spectrometry, Talanta, 82, 1261-1270. Kvalheim OM, Grung B, Nodland E, Rajalahti T (2010): The 11th Scandinavian Symposium on Chemometrics, Loen, Norway, 8-11 June 2009, Journal of Chemometrics, 24, 343-345. Mjøs SA, Grung B (2009): A rank annihilation approach to reducing the scan-effect in gas chromatography-mass spectrometry data, Analytica Chimica Acta, 640, 33-39. Flåten GR, Grung B, Kvalheim OM (2007): A comparison of different pre-treatment procedures for reducing heteroscedasticity and other irrelevant features in data prior to modelling of benthic count profiles, Journal of Chemometrics, 21, 386-396 ...
The invention discloses a new interface with non-circular conductance limit aperture(s) useful for effective transmission of non-circular ion beams between stages with different gas pressure. In particular, the invention provides an improved coupling of field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers of planar or side-to-side geometry to downstream stages such as mass spectrometry or ion mobility spectrometry. In this case, the non-circular aperture is rectangular; other geometries may be optimum in other applications. In the preferred embodiment, the non-circular aperture interface is followed by an electrodynamic ion funnel that may focus wide ion beams of any shape into tight circular beams with virtually no losses. The jet disrupter element of the funnel may also have a non-circular geometry, matching the shape of arriving ion beam. The improved sensitivity of planar FAIMS/MS has been demonstrated in experiments using a non-contiguous elongated aperture but other embodiments (e
Gloria Ulasi is a PhD student. Her project title is High Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) and Mass Spectrometry for Proteomics. The project aims to develop FAIMS coupled to liquid chromatography tandem mass spectrometry with electron transfer dissociation (ETD) and collision induced dissociation (CID) for analysing complex proteomics samples with particular emphasis on post-translational modifications (PTMs), such as glycosylation.. One aspect of the project is to apply the LC-FAIMS-MS/MS approach to investigate glycosylation in Campylobacter jejuni (C. jejuni NCTC 11168). C. jejuni is the leading cause of gastroenteritis world-wide. The Fla A protein of C. jejuni has been found to be highly glycosylated and it has also been linked to the virulence of C. jejuni.. ...
Mass spectrometry has become an invaluable tool to a wide range of biological, chemical, and physical research endeavors. It is routinely used in both the pharmaceutical and biotechnology industries, as well as the environmental field and for homeland security applications. Electrospray and nanospray ionization, especially when mated to separations techniques, have become one of the indispensable techniques for biomolecular analysis. The use of both of these methods in the course of this research has resulted in the identification and verification of a reported glutathione thionitrate species. Supporting evidence for its existence was also obtained through the use of ESI/Nanospray mated to quadrupole ion trap mass spectrometry. In addition, a suspected internal sulfonamide species was investigated and tandem MS data were obtained which shed light into its structure. The separation technique of gas chromatography was mated with electron impact ionization and mass spectrometry to identify VOC ...
A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus ...
Pyrolysis and mass spectrometry studies of meteoritic organic matter Mass Spectrometry Reviews , 2012, 31 , 560-569 M.A. Sephton Abstract Meteorites are fragments of extraterrestrial materials that fall to the Earths surface. The carbon-rich meteorites are derived from ancient asteroids that have remained relatively unprocessed since the...
Wong, C., K.L.; Chan, T.W.Dominic, 1997: Cationization processes in matrix-assisted laser desorption/ionization mass spectrometry: Attachment of divalent and trivalent metal ions
Gruisen, J.A.E. (2019) Matrix-assisted laser desorption/ionisation mass spectrometry imaging for bone fracture hematoma analysis. Full text not available from this repository. ...
Rapid and Highly Accurate Detection of Steryl Glycosides by Ultraperformance Liquid Chromatography−Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-TOF-MS ...
Figure 11: ESI-mass spectra of cyt c in water containing 3% methanol and 0.5 mM ammonium acetate at (a) pH 6.4, (b) pH 4.2, (c) pH 2.6, and (d) pH 2.3. The pH was adjusted by the addition of hydrochloric acid. (Reprinted with permission from Biochemistry [80], Copyright 1997, American Chemical Society ...
A mammalian N-acetylglucosamine (GlcNAc) transferase I (GnT I)-independent fucosylation pathway is revealed by the use of matrix-assisted laser desorption/ionization (MALDI) and negative-ion nano-electrospray ionization (ESI) mass spectrometry of N-linked glycans from natively folded recombinant glycoproteins, expressed in both human embryonic kidney (HEK) 293S and Chinese hamster ovary (CHO) Lec3.2.8.1 cells deficient in GnT I activity. The biosynthesis of core fucosylated Man5GlcNAc2 glycans was enhanced in CHO Lec3.2.8.1 cells by the alpha-glucosidase inhibitor, N-butyldeoxynojirimycin (NB-DNJ), leading to the increase in core fucosylated Man5GlcNAc2 glycans and the biosynthesis of a novel core fucosylated monoglucosylated oligomannose glycan, Glc1Man7GlcNAc2Fuc. Furthermore, no fucosylated Man9GlcNAc2 glycans were detected following inhibition of alpha-mannosidase I with kifunensine. Thus, core fucosylation is prevented by the presence of terminal alpha1-2 mannoses on the 6-antennae but not the 3
Electrospray ionization (ESI) mass spectrometry (MS) in combination with liquid chromatography (LC) is an excellent tool for the identification of drug metabolites. Utilizing this hyphenated technique in combination with proper sample pretreatment, the metabolic pathways of the analgesic drug ketobemidone were investigated in human urine and rat microdialysate from blood and brain. Two novel phase I metabolites (ketobemidone N-oxide and meta-hydroxymethoxyketobemidone) and three novel phase II metabolites (glucuronic acid conjugates of ketobemidone, norketobemidone and hydroxymethoxyketobemidone) were identified in human urine. Further, norketobemidone and ketobemidone N-oxide were identified in rat microdialysate from brain after regional distribution of ketobemidone in striatum. This indicates that the brain itself has the possibility to metabolize ketobemidone. Synthetic ketobemidone metabolites were used for comparison of retention times and tandem MS spectra with the possible metabolites ...
Polynuclear platinum compounds represent a new class of potential platinum anticancer therapeutics. Derived from the most widely used platinum anticancer drug, cisplatin, these novel compounds are distinct in their interactions with bio-molecules. The effectiveness of platinum anticancer agents is influenced by three pharmacological factors: (i) their resistance to deactivating sulfur nucleophiles, (ii) the ability to gain cellular entry and efficient cellular uptake, and (iii) the ability to form stable and specific complexes with DNA. BBR 3464, the first multinuclear platinum compound to reach phase II clinical trials, has created a new approach to cancer drug design. Large, highly charged platinum compounds have been shown to form favorable covalent and noncovalent interactions with bio-molecular structures. Compounds such as BBR 3464, form an immediate pre-association with anionic structures on biomolecules before covalent attachment. To better characterize these interactions, a new set of
Derivatisation for the characterisation of neutral oxosteroids by electrospray and matrix-assisted laser desorption/ionisation tandem mass spectrometry: The Girard P derivative / W.J. Griffiths; S. Liu; G. Alvelius; J. Sjövall; William Griffiths ...
0059] FIG. 12 includes plots for CH, NOS, N1S2, N2, S1 and S2 classes obtained for Light Sour crude oil with TMAH. The signal for these classes is either absent (CH, NOS, NS2, S2 classes) or very week (N2, S1 classes) at the use of NH4OH. Thus, TMAH provides significantly improved information and is suitable for detection of classes with a higher heteroatom content. Hydrocarbon class (CH) appears at a DBE of 9-24, which indicate condensed polycyclic structures. A lower DBE observed is 9 and is likely to correspond to fluorenyl anion (alkyl) derivatives. As discussed above such cyclic compounds can be deprotonated from the sp3 carbon in the presence of an extremely strong base to generate resonance-stabilized carbanions. NOS, N1S2, N2 classes are detected in the wide range of DBE (from 9 to over 30) and Carbon number (from 20 to 70) and appear to have either pyrolic nitrogen (NOS, N1S2, N2 classes), or/and thio-group (NOS, N1S2 classes) or/and phenolic group (NOS class). S1 and S2 classes contain ...
The International Journal of Analytical Chemistry is a peer-reviewed, Open Access journal that publishes original research articles reporting new experimental results and methods, especially in relation to important analytes, difficult matrices, and topical samples. Focussed review articles are also welcomed.
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If you have a question about this talk, please contact Dr Konstantin Barylyuk.. Abstract not available. This talk is part of the Seminars at the Department of Biochemistry series.. ...
Abraham Badu-Tawiah obtained his Ph.D. (2012) in Chemistry with R. Graham Cooks at Purdue University. During that time he worked on the mechanism of desorption electrospray ionization, which led to the development of novel instrumentation for ambient ion soft landing, and ionic reactions with neutral species adsorbed on ambient surfaces. This training in ion manipulation at atmospheric pressure laid the ground work for the creation of analytical devices that permit ion chemistry to be performed more effectively using charged micro-droplets as reaction vessels. During his time at Purdue, Dr. Badu-Tawiah was awarded Andrews (2007 - 2009), Bilsland Dissertation (2011), and Lilly Innovative (2012) Fellowships. From 2012 to 2014, he was a postdoctoral fellow at Harvard University under the direction of George M. Whitesides, where his research focused on the development of methods for performing molecular recognition (immunoassay) on ambient paper surfaces for use in resource-limited disease ...
TY - CHAP. T1 - Automated cell-by-cell tissue imaging and single-cell analysis for targeted morphologies by laser ablation electrospray ionization mass spectrometry. AU - Li, Hang. AU - Smith, Brian K.. AU - Shrestha, Bindesh. AU - Márk, L.. AU - Vertes, Akos. PY - 2014/10/31. Y1 - 2014/10/31. N2 - Mass spectrometry imaging (MSI) is an emerging technology for the mapping of molecular distributions in tissues. In most of the existing studies, imaging is performed by sampling on a predefined rectangular grid that does not reflect the natural cellular pattern of the tissue. Delivering laser pulses by a sharpened optical fiber in laser ablation electrospray ionization (LAESI) mass spectrometry (MS) has enabled the direct analysis of single cells and subcellular compartments. Cell-by-cell imaging had been demonstrated using LAESI-MS, where individual cells were manually selected to serve as natural pixels for tissue imaging. Here we describe a protocol for a novel cell-by-cell LAESI imaging approach ...
The possibility of using capillary electrophoresis-electrospray ionisation (ESI)/MS to separate and quantify cobalt and iron was explored. It was necessary to tackle and overcome problems from different sources, some of them being rather unpredictable. The results obtained suggest the occurrence of oxidation processes of metal ions during the formation of the electrospray. The quantitative oxidation of cobalt(II) to cobalt(III), a process at our knowledge never described before, appears particularly interesting. The results obtained, though not optimised for sensitivity appear promising, since a limit of detection of the order of tenths of picograms was obtained. Further, from the comparison with the results obtained by optical detection, the use of CE-ESI/MS appears advantageous. (c) 2007 Elsevier B.V. All rights reserved.. The possibility of using capillary electrophoresis-electrospray ionisation (ESI)/MS to separate and quantify cobalt and iron was explored. It was necessary to tackle and ...