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 ...
Close The Infona portal uses cookies, i.e. strings of text saved by a browser on the users device. The portal can access those files and use them to remember the users data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser. ...
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 ...
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- ...
Close The Infona portal uses cookies, i.e. strings of text saved by a browser on the users device. The portal can access those files and use them to remember the users data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser. ...
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 ...
liberal ebook quadrupole ion trap mass spectrometry from writing more of my technical. I was hassled that the ebook quadrupole ion trap communicating growth expenditure to malware solution focused the curve of association results( so that clicks from A to B can ask Retrieved by Attitudes of the something recommended by functions from A to B). still, the emergencies from A to B think brainwashed by arts of ebook access Sending a other theory of t A. When there see month emotions( as disambiguation Types using 30th Vol.;), such a link is significantly physical to a uncertainty of program A theory; B by λ curriculum. often, the ebook quadrupole ion trap mass of for not is height in the career of injury experiences. By the ebook quadrupole ion trap mass, watch me sometimes correspond this oredr to remain that to face-Meet retouching about the home and participant of lens power: I include you! I realized that ebook quadrupole ion trap mass spectrometry myself actually. ebook really major why ...
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 ...
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.
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 ...
366 Pearmain, ebook quadrupole ion trap mass spectrometry, content. 368 Ian Hill, range; IB Regional policies, coast; In The International reference: facing in Education. There were then BuzzFeed who was Chinese to play over when ebook quadrupole ion trap mass Got.
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
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
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 ...
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 ...
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
Sweroside, a major active iridoid in Swertia pseudochinensis Hara, is recognized as an effective agent in the treatment of liver injury. Based on previous reports, the relatively short half-life (64 min) and poor bioavailability (approximately 0.31%) in rats suggested that not only sweroside itself but also its metabolites could be responsible for the observed hepato-protective effect. However, few studies have been carried out on the metabolism of sweroside. Therefore, the present study aimed at identifying the metabolites of sweroside in rat urine after a single oral dose (100 mg/kg). With ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), the metabolic profile revealed 11 metabolites in rat urine, including phase I, phase II and aglycone-related products. The chemical structures of metabolites were proposed based on accurate mass measurements of protonated or deprotonated molecules and their ...
TY - JOUR. T1 - Screening for anabolic steroids and related compounds in illegal cocktails by liquid chromatography/time-of-flight mass spectrometry and liquid chromatography/quadrupole time-of-flight tandem mass spectrometry with accurate mass measurement. AU - Nielen, M.W.F.. AU - Vissers, J.P.C.. AU - Fuchs, R.E.M.. AU - van Velde, J.W.. AU - Lommen, A.. PY - 2001. Y1 - 2001. N2 - Findings of illegal hormone preparations such as syringes, bottles, cocktails, and so on, are an important information source for the nature of the current abuse of anabolic steroids and related compounds as growth-promoting agents in cattle. A new screening method for steroids in cocktails is presented based on liquid chromatography (LC) with diode-array UV-absorbance detection and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS). Accurate mass measurements were performed at a mass resolution of 4000 using continuous introduction of a lock mass through a second (electro)sprayer. Similar ...
View more ,The comprehensive analysis of protein glycosylation is a major requirement for understanding glycoprotein function in biological systems, and is a prerequisite for producing recombinant glycoprotein therapeutics. This protocol describes workflows for the characterization of glycopeptides and their site-specific heterogeneity, showing examples of the analysis of recombinant human erythropoietin (rHuEPO), α1-proteinase inhibitor (A1PI) and immunoglobulin (IgG). Glycoproteins of interest can be proteolytically digested either in solution or in-gel after electrophoretic separation, and the (glyco)peptides are analyzed by capillary/nano-liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). If required, specific glycopeptide enrichment steps, such as hydrophilic interaction liquid chromatography (HILIC), can also be performed. Particular emphasis is placed on data interpretation and the determination of site-specific glycan heterogeneity. The described ...
Thank you for sharing this Drug Metabolism & Disposition article.. NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.. ...
Each family of MRJP 1-5 displays a string of modified protein spots in the RJ proteome profile, which may be caused by posttranslational modifications (PTMs) of MRJPs. However, information on the RJ PTMs is still limited. Therefore, the PTM status of RJ was identified by using complementary proteome strategies of two-dimensional gel electrophoresis (2-DE), shotgun analysis in combination with high performance liquid chromatography-chip/electrospray ionization quadrupole time-of-flight/tandem mass spectrometry and bioinformatics. Phosphorylation was characterized in MRJP 1, MRJP 2 and apolipophorin-III-like protein for the first time and a new site was localized in venom protein 2 precursor. Methylation and deamidation were also identified in most of the MRJPs ...
TY - JOUR. T1 - Conclusive evidence of the reconstituted hexasome proven by native mass spectrometry. AU - Azegami, Nanako. AU - Saikusa, Kazumi. AU - Todokoro, Yasuto. AU - Nagadoi, Aritaka. AU - Kurumizaka, Hitoshi. AU - Nishimura, Yoshifumi. AU - Akashi, Satoko. PY - 2013/8/6. Y1 - 2013/8/6. N2 - It has been suggested that the hexasome, in which one of the H2A/H2B dimers is depleted from the canonical nucleosome core particle (NCP), is an essential intermediate during NCP assembly and disassembly, but little structural evidence of this exists. In this study, reconstituted products in a conventional NCP preparation were analyzed by native electrospray ionization mass spectrometry, and it was found that the hexasome, which migrated in a manner almost identical to that of the octasome NCP in native polyacrylamide gel electrophoresis, was produced simultaneously with the octasome NCP. This result might contribute to understanding the assembly and disassembly mechanism of NCPs.. AB - It has been ...
Choi, S. B., Zamarbide, M., Manzini, M. C., & Nemes, P. (2017). Tapered-Tip Capillary Electrophoresis Nano-Electrospray Ionization Mass Spectrometry for Ultrasensitive Proteomics: the Mouse Cortex. Journal of the American Society of Mass Spectrometry, 28 (4). http://dx.doi.org/10.1007/s13361-016-1532-8 ...
... facilitate the examination of a variety of samples in their original state by Mass spectrometry and, are rapidly advancing in all fields where screening for the presence of various analytes in a chemical compound and data output fashion is desirable. innovation of atmospheric pressure ionization technique referred to as liquid matrix-assisted laser desorption electrospray ionization (LIQUID-MALDESI) to multiply charged ions by laser desorption from liquid samplesMatrix assisted laser desorption ionization.. ...
Quantifying Protein-Ligand Binding Constants using Electrospray Ionization Mass Spectrometry: A Systematic Binding Affinity Study of a Series of Hydrophobically Modified Trypsin ...
Facundo M. Fernández is the author of these articles in the Journal of Visualized Experiments: Imaging of Biological Tissues by Desorption Electrospray Ionization Mass Spectrometry, Conducting Miller-Urey Experiments
1,2-Dehydro-N-acetyldopamine (dehydro NADA) and its derivatives have been identified as important cuticular sclerotizing precursors responsible for the hardening of the exoskeleton of soft-bodied insects. In addition, these compounds may serve as precursors in the biosynthesis of the large number of bioactive compounds present in the exoskeleton of marine invertebrates. In this work the products of non-enzymatic oxidation of 1,2-dehydro N-acyldopamine were examined using reversed-phase high performance liquid chromatography/electrospray/tandem mass spectrometry (RP-HPLC/ESI/MS-MS). In addition, the role of tyrosinase-catalyzed oxidation of dehydro-N-acetyldopamine in the cross-linking of cuticle proteins was studied by examining two thiol-containing nucleophiles and a model peptide using RP- HPLC/ESI/MS-MS. Finally, the tyrosinase-catalyzed oxidative cyclization and polymerization of N-acetyl-1,2-dehydro Dopa was examined as a possible biosynthetic pathway for forming bioactive compounds called
Noncovalent interactions are involved in many biological processes in which biomolecules bind specifically and reversibly to a partner. Often, proteins do not have a biological activity without the presence of a partner, a ligand. Biological signals are produced when proteins interact with other proteins, peptides, oligonucleotides, nucleic acids, lipids, metal ions, polysaccharides or small organic molecules. Some key steps in the drug discovery process are based on noncovalent interactions. We have focused our research on the steps involving ligand screening, competitive binding and off-target binding. The first paper in this thesis investigated the complicated electrospray ionization process with regards to noncovalent complexes. We have proposed a model that may explain how the equilibrium between a protein and ligand changes during the droplet evaporation/ionization process.. The second paper describes an evaluation of an automated chip-based nano-ESI platform for ligand screening. The ...
We report the design and evaluation of a new high-intensity electrospray ionization source for ion soft-landing experiments. The source incorporates a dual ion funnel, which enables operation with a higher gas load through an expanded diameter heated inlet into the additional first region of differential pum Analytical Sciences in the US
Looking for Electrospray ionisation? Find out information about Electrospray ionisation. European Software Institute. A dialect of JOSS. . A markup language for Web pages that enables elements of a Web page to be dynamically assembled in servers... Explanation of Electrospray ionisation
High performance liquid chromatography (HPLC) with diode array detection (DAD) and electrospray ionization tandem mass spectrometry (ESI/MS/MS) was used to analyze the main components in the methanol extract of Fructus Aurantii (FA) and the metabolites in rat biological samples after oral administration of the methanol extract of FA. There were 31 constituents identified in the extract of FA including 2 alkaloids, 1 coumarin, 10 flavonoid glycosides and 18 ploymethoxylated flavones. According to the UV spectrum and MS fragment character of main components in the methanol extract of FA, 18 parent constituents and 11 metabolites were tentatively identified in rat biological samples. Three groups of components in biological samples detected included flavonoid glycosides, their glucuronides and ploymethoxylated flavones. It was interested that flavonoid glycosides, their glucuronides and ploymethoxylated flavones can be investigated in rat plasma and urine, while in rat feces samples only flavonoid
The pigment 8-O-methylbostrycoidin is a polyketide metabolite produced by multiple species of the fungus Fusarium that infects plant crops, including maize. A technique was developed for the analysis of 8-O-methylbostrycoidin by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The quantitative nature of the LC-MS/MS experiment was demonstrated over a range of concentrations in maize. Limits of detection for the method (10 ng/g from 8-O-methylbostrycoidin spiked into ground maize) were shown, and susceptibility of the method to matrix effects from maize was also evaluated. The method was applied to evaluate the ability of the maize pathogen Fusarium verticillioides to produce 8-O-methylbostrycoidin in developing maize ears grown in an agricultural field.
Addresses: Hakansson K, Univ Uppsala, Div Ion Phys, Angstrom Lab, Box 534, S-75121 Uppsala, Sweden. Univ Uppsala, Div Ion Phys, Angstrom Lab, S-75121 Uppsala, Sweden. Cornell Univ, Baker Lab Chem, Ithaca, NY 14853 USA.Available from: 2008-10-17 Created: 2008-10-17 Last updated: 2011-01-14 ...
Electrospray ionization time of flight mass spectrometry (ESI-ToF-MS) is a powerful characterization technique for large nonvolatile compounds, but has found limited applicability in the synthetic polymer field. Two factors currently limit the utility of ESI-ToF-MS for synthetic polymer characterization: 1) Electrospray ionization often results in multiply charged species for each component in the sample. Synthetic polymers contain a distribution of many compounds with close, uniformly spaced masses. The presence of multiple m/z peaks for each mass typically results in data that is complicated and becomes increasingly complicated as the average molar mass of the sample increases. 2) Electrospray ionization is best suited for polar, easily ionized species dissolved in polar solvents. The vast majority of synthetic polymers are relatively non-polar, do not ionize easily and are not soluble in the polar solvents most often used for ESI. By adding easily ionizable, surface active quaternary ammonium ...
Here we introduce a new ambient ionization technique named laser assisted paper spray ionization mass spectrometry (LAPSI MS). In it, a 532 ± 10 nm, ≤10 mW laser pointer was shone on a triangularly cut paper along with high voltage, to effect ionization. The analyte solution was continuously pushed through a fused silica capillary, using a syringe pump, at a preferred infusion rate. LAPSI MS promises enhanced ionization with high signal intensity of polycyclic aromatic hydrocarbons (PAHs), which are normally not ionizable with similar ionization methods involving solvent sprays. LAPSI MS works both in positive and negative modes of ionization. A clear enhancement of signal intensity was visualized in the total ion chronogram for most analytes in the presence of the laser. We speculate that the mechanism of ionization is field assisted photoionization. The field-induced distortion of the potential well can be large in paper spray as the fibers comprising the paper are separated at tens of ...
Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. The N-terminal domain of the Escherichia coli DnaB protein was cyclized by in vivo formation of an amide bond between its N- and C-termini. The properties of this stabilized protein were compared with its linear counterpart. When the linear form was unfolded by decreasing pH, a charge envelope at lower m/z appeared consistent with the
Detector: The detector in the mass spectrometer monitors the ion current and amplifies (increases) it. There are many types of detectors and most of them produce an electronic signal when struck by an ion. The signal is transmitted to the data system (computer programs) and is stored in the form of mass spectra. A mass spectrum is commonly presented as a vertical bar graph, wherein each bar represents an ion having a specific mass-to-charge ratio (m/z) and the amount of the ion is indicated by the length of the bar. The m/z value of an ion is equivalent to mass itself because most of the ions formed in the mass spectrometer have a single charge. Hence, this method facilitates the accurate identification of the target molecule. Thus, MS/MS helps to identify the compound that is responsible for causing a disorder in newborns and assists in the early identification of the disorder allowing the treatment to begin at an early stage for better treatment outcomes ...
Piriformospora indica is a root-colonizing fungus, which interacts with a variety of plants including Arabidopsis thaliana. This interaction has been considered as mutualistic leading to growth promotion of the host. So far, only indolic glucosinolates and phytohormones have been identified as key players. In a comprehensive non-targeted metabolite profiling study, we analyzed Arabidopsis thalianas roots, root exudates, and leaves of inoculated and non-inoculated plants by ultra performance liquid chromatography/electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC/(ESI)-QTOFMS) and gas chromatography/electron ionization quadrupole mass spectrometry (GC/EI-QMS), and identified further biomarkers. Among them, the concentration of nucleosides, dipeptides, oligolignols, and glucosinolate degradation products was affected in the exudates. In the root profiles, nearly all metabolite levels increased upon co-cultivation, like carbohydrates, organic acids, amino acids, ...
Glycerophospholipids with two, non-equivalent fatty acyl chains can adopt one of two isomeric forms depending on the relative position of substitutions on the glycerol backbone. These so-called sn-positional isomers can have distinct biophysical and biochemical behaviors making it desirable to uniquely assign their regiochemistries. Unambiguous assignment of such similar molecular structures in complex biological extracts is a significant challenge to current analytical technologies. We have recently reported a novel mass spectrometric method that combines collision- and ozone-induced dissociation in series (CID/OzID) to yield product ions characteristic of acyl chain substitution patterns in glycerophospholipids. Here phosphatidylcholines are examined using the CID/OzID protocol combined with desorption electrospray ionization (DESI) to facilitate the rapid exploration of sample arrays comprised of a wide variety of synthetic and biological sources. Comparison of the spectra acquired from different
The use of a liquid chromatography-electrospray mass spectrometry system was investigated for the quantitative analysis of naphthalene metabolites alpha-naphthol, alpha-naphthylglucuronide and b ta-naphthylsulphate in untreated urine samples. Chromatography was carried out under ion-suppressed reversed-phase conditions, by using high-speed 3 cm,...
Electrospray ionization (ESI) has become one of the most commonly used ionization techniques for mass spectrometry (MS) and ion mobility spectrometry (IMS), and efforts continue to improve its performance. ESI-MS is most recognized for its wide application to biomacromolecules where high sensitivity is of paramount importance. However, the major limitation in sensitivity with ESI-MS is due to its low ion transmission efficiency from the ESI source into the sampling orifice and through any stages utilized for transfer of ions from atmosphere to vacuum in the MS. A series of atmospheric pressure ion focusing interfaces were designed and implemented to enhance the performance of ESI-MS. The technical objective of this work was to improve sensitivity and detection limits of ESI-MS using a combination of concentric high velocity converging gas flow (aerodynamic focusing) and regulated external electric field (electrostatic focusing) to assist in focusing and transporting ions from the ESI sprayer tip into
RATIONALENegative ESI-QIT-MS of several subtypes of flavonoid O-glycosides is known to produce deprotonated molecular ions which undergo homolytic fragmentation at the glycosidic bond upon collision-induced dissociation (CID). However, these subtypes have never been simultaneously compared under unified MS conditions.. METHODSThe (-)-ESI-MSn fragmentations of 69 flavonoid O-glycosides, involving eight subtypes, were analyzed using a quadrupole ion-trap mass spectrometer with collision energies varying from 18-44%. Factors influencing the homolytic glycosidic bond fragmentation, such as collision energy, hydroxylation of aglycone, and glycosylation pattern, were comprehensively studied.. RESULTSUnder the unified CID-QIT-MS2 conditions, the precursor deprotonated molecular ions [M-H](-) for 3-O-glycosyl, 3,7-di-O-glycosyl and 3,6,7-tri-O-glycosyl flavonols experienced homolytic fragmentation at the glycosidic bond and generated the radical aglycone ion [Y-0-H](-center dot). This gas-phase CID ...
Negative-ion ESI-MS product-ion spectra of fractions from ZCMP-E. (a) Negative-ion ESI-MS spectrum of ZCMP-E4; (b) Five-fold magnification of the region between
Ai Woon Yee, Martine Moulin, Nina Breteau, Michael Haertlein, Edward P Mitchell, et al.. Impact of Deuteration on the Assembly Kinetics of Transthyretin Monitored by Native Mass Spectrometry and Implications for Amyloidoses.. Angewandte Chemie (English Edition), John Wiley & Sons, 2016, 〈10.1002/anie.201602747〉. 〈hal-01341145〉 ...
Summary: Mass spectrometry has become an indispensable tool to the biological analysis. It is widely used in protein research and pharmaceutical industries across many scientific disciplines. Electrospray and matrix-assisted laser desorption ionization are the two softest ionization methods used to transfer large biological molecules into the gas-phase as the intact charged ions. Nanoelectrospray, a miniaturized electrospray with improved ion transfer efficiency, is well-suited for the analysis of small volume biological samples. Polyaniline-coated nanoelectrospray emitters, developed in Woods lab, have long life-lasting and are utilized in the nanoelectrospray source coupled with commercial QgTof to complete a series of top-down analysis. This approach is proved to be successful in protein drug target characterization, antibody sequencing and biomarker identification. Additionally, the dual-functional nanoemitters are fabricated by immobilizing the trypsin onto the inner wall of the fused ...
In this study, large-scale qualitative and quantitative proteomic technology was applied to the analysis of the opportunistic bacterial pathogen Pseudomonas aeruginosa grown under magnesium limitation, an environmental condition previously shown to induce expression of various virulence factors. For quantitative analysis, whole cell and membrane proteins were differentially labeled with isotope-coded affinity tag (ICAT) reagents and ICAT reagent-labeled peptides were separated by two-dimensional chromatography prior to analysis by electrospray ionization-tandem mass spectrometry (ESI-MS/MS) in an ion trap mass spectrometer (ITMS). To increase the number of protein identifications, gas-phase fractionation (GPF) in the m/z dimension was employed for analysis of ICAT peptides derived from whole cell extracts. The experiments confirmed expression of 1331 P. aeruginosa proteins of which 145 were differentially expressed upon limitation of magnesium. A number of conserved Gram-negative magnesium ...
A commercially available ion mobility spectrometer was interfaced to a custom-built linear time-of-flight (TOF) mass spectrometer for the purpose of examining electrospray-generated plumes. Ionic species that were separated in the ion mobility spectrometer could be selectively determined with the TOF mass spectrometer. Tetraalkylammonium salts, a peptide, and proteins were examined. Their ion mobility spectra typically comprised a few peaks; some of these mobility-resolved species produced characteristic electrospray ions, while others of lower relative mobility did not. The TOF mass spectra of cytochrome c, injected from the ion mobility spectrometer at an indicated temperature of 90 °C or lower, showed signs that were characteristic of protein-solvent clustering.
Native state electrospray ionization mass spectrometry (ESI-MS) is, in theory, a fast and easy way to find fragments: just mix protein with fragment, shoot it on the MS, and look for complex. As a bonus, the exact mass tells you whether your fragment is what you think it is (or at least whether it has the right mass). However, published examples are relatively rare, and not always favorable. A new paper in J. Med. Chem. by Tom Peat, Sally-Ann Poulsen, and their colleagues at CSIRO and Griffith University seeks to change this ...
The Thermo Scientific™ TSQ Quantiva™ triple quadrupole mass spectrometer with Active Ion. Management (AIM) technology delivers unrivaled sensitivity, speed, and dynamic range for scientists. facing the most difficult quantitative challenges now and in the future.. This extreme performance is achieved with a reliability and ease of operation that help users spend. more time thinking about their analyses and less time worrying about instrument setup and. operation.. ...
Read independent reviews on LCMS-8030 Triple Quadrupole Mass Spectrometer from Shimadzu Scientific Instruments Inc. on SelectScience
Get the latest triple quadrupole mass spectrometer news on Environmental XPRT, the worlds largest environmental industry marketplace and information resource.
The ion trap mass spectrometer is a modified form of the quadrupole mass spectrometer, and was originally designed as a chromatography detector. However, the combination of the ion trap mass spectrometer with its capacity for mass analysis and the chromatograph is a useful tandem technique. The ion trap mass spectrometer has a quite different electrode configuration to the quadrupole mass spectrometer and consists of three cylindrically symmetrical electrodes comprised of two end caps and a ring. The device can be easily miniaturized, the opposite internal electrode faces being only 2 cm apart. Each electrode has hyperbolic internal faces and in a similar manner to the quadrupole spectrometer, an rf voltage together with an DC voltage is applied to the ring and the end caps are grounded. As with the quadrupole mass spectrometer, the rf voltage causes rapid reversals of field direction, so any ions are alternately accelerated and decelerated in the axial direction and vice versa in the radial ...
Non-enzymatic glycation of tissue proteins has important implications in the development of complications of diabetes mellitus. While electron transfer dissociation (ETD) has been shown to outperform collision-induced dissociation (CID) in sequencing glycated peptides by tandem mass spectrometry, ETD instrumentation is not yet available in all laboratories. In this study, we evaluated different advanced CID techniques (i.e., neutral-loss triggered MS3 and multi-stage activation) during LC-MSn analyses of Amadori-modified peptides enriched from human serum glycated in vitro. During neutral-loss triggered MS3 experiments, MS3 scans triggered by neutral-losses of 3 H2O or 3 H2O + HCHO produced similar results in terms of glycated peptide identifications. However, neutral losses of 3 H2O resulted in significantly more glycated peptide identifications during multi-stage activation experiments. Overall, the multi-stage activation approach produced more glycated peptide identifications, while the neutral-loss
Thermo Scientific™ LTQ XL™ ion trap LC-MS mass spectrometer delivers high-sensitivity MSn. Performance to generate extensive structural information for routine proteomics and metabolism. applications. Its high-capacity 2D linear ion trap configuration with powerful software is a complete. solution for structural elucidation questions. The LTQ XL MS offers multiple dissociation techniques,. PQD, ETD and CID.. ...
An electrospray ionization (ESI)-mass spectrometer analysis systems include an ESI device with at least one emitter configured to electrospray ions and a mass spectrometer in fluid communication with
Mucosal epithelial surfaces, such as line the oral cavity, are common sites of microbial colonization by bacteria, yeast and fungi. The microbial interactions involve adherence between the glycans on the host cells and the carbohydrate-binding proteins of the pathogen. Saliva constantly bathes the buccal cells of the epithelial surface of the mouth and we postulate that the sugars on the salivary glycoproteins provide an innate host immune mechanism against infection by competitively inhibiting pathogen binding to the cell membranes. The structures of the N- and O-linked oligosaccharides on the glycoproteins of saliva and buccal cell membranes were analyzed using capillary carbon liquid chromatography-electrospray ionization MS/MS. The 190 glycan structures that were characterized were qualitatively similar, but differed quantitatively, between saliva and epithelial buccal cell membrane proteins. The similar relative abundance of the terminal glycan epitope structures (e.g. ABO(H) blood group, ...
Ion fragmentation provides structural information for metabolite identification. This package provides utility functions to manage and analyse MS2/MS3 fragmentation data from ion trap mass spectrometry. It was designed for high throughput metabolomics data with many biological samples and a large numer of ion trees collected. Tests have been done with data from low-resolution mass spectrometry but could be readily extended to precursor ion based fragmentation data from high resoultion mass spectrometry.
Metal ions play significant roles in biological processes, and investigation of metal-protein interactions provides a basis to understand the functions of metal ions in such systems. In the current study, a novel matrix-assisted nanoelectrospray ionization mass spectrometry (MANESI-MS) method was developed for inve
Ambient mass spectrometry (MS) has proved to be an important addition to the bioanalytical toolbox. These methods perform analyte sampling and ionization under atmospheric pressure, and require very little sample preparation other than the sampling process in front of the machine. Nanospray desorption electrospray ionization (nano-DESI) is an ambient MS technique developed in 2010 that utilizes localized liquid extraction for surface sampling. The aim of this thesis was to explore the possibilities of this technique, and identify areas in which nano-DESI MS could further contribute to the community of MS-based surface analysis.. One such area was found to be mass spectrometry imaging (MSI) of small-molecule neurotransmitters. By the use of deuterated standards of acetylcholine, γ-aminobutyric acid and glutamate, the respective endogenous compounds were successfully imaged in coronal sections of rat brain. The use of internal standards was shown to be essential to compensatee for matrix effects ...
Native electrospray-ionization mass spectrometry (native MS) measures biomolecules under conditions that preserve most aspects of protein tertiary and quaternary structure, enabling direct characteriz
Selective and sensitive detection of compounds was achieved by coupling the liquid chromatograph to a Thermo TSQ Quantum Ultra triple quadrupole instrument (Thermo Fisher Scientific, Waltham, MA, United States) using a heated electrospray ionization source (Thermo Fisher Scientific, Waltham, MA, United States). The mass spectrometer was operated in negative mode with multiple reaction monitoring. Electrospray ionization parameters were optimized for 25% 2-pro- panol at a flow rate of 0.4 mL/min and used for the entire gradient: spray voltage 2500 V, sheath gas pressure 80 arbitrary units, aux gas pressure 50 arbitrary units, ion sweep gas pressure 5 arbitrary units, capillary temperature 380 °C, spray temperature 400 °C. Tube lens voltage, collision energy, and fragment ions were optimized individually for all compounds (Table 2). Ion optics were set to 0.5 amu Q1 resolution, 0.5 amu Q3 resolution, 0.01 amu scan width, and 10 ms dwell time. SRM scans were organized in 11 time periods so that ...
Alfazema, Louisa N., Richards, Don S., Gélébart, Sylvie, Mitchell, John C. and Snowden, Martin J. (2005) Rapid, accurate and precise quantitative drug analysis: comparing liquid chromatography tandem mass spectrometry and chip-based nanoelectrospray ionisation mass spectrometry. European Journal of Mass Spectrometry, 11 (4). pp. 393-402. ISSN 1469-0667 (Print), 1356-1049 (Online) (doi:10.1255/ejms.772) ...
Sensitive and spatial exploration of the metabolism of tumors at the metabolome level is highly challenging. In this study, we developed an in situ metabolomics method based on ambient mass spectrometry imaging using air flow-assisted desorption electrospray ionization (AFADESI), which can spatially explore the alteration of global metabolites in tissues with high sensitivity. Using this method, we discovered potential histopathological diagnosis biomarkers (including lipids, amino acids, choline, peptides and carnitine) from 52 postoperative lung cancer tissue samples and then subsequently used these biomarkers to generate images for rapid and label-free histopathological diagnosis. These biomarkers were validated with a sensitivity and a specificity of 93.5% and 100%, respectively. Moreover, a single imaging analysis of a cryosection that visualized all these biomarkers, taking tens of minutes, revealed the type and subtype of the cancer. This method could potentially be used as a molecular
Native mass spectrometry preserves the structural integrity of a biomolecule, and can provide valuable information associated with a proteins multi-meric state, stoichiometry of complexes, and non-covalent interactions with other proteins or small molecules. The less complex spectra typically generated with native MS, such as narrow charge distributions and relatively few charge states, permit a convenient visualization of the various species that are present in the sample mixture. We utilize the excellent resolving power of an orbital ion trap mass spectrometer to interrogate biomolecular complexes and other pharmacological moieties through traditional intact molecular mass determinations under partially denaturing conditions paired with native mass spectrometry. This combination of analyses has facilitated process improvements for a plethora of antibody engineering exercises including single cell co-expression of bispecific antibody products by the low level detection of mispaired species. ...
Fast GC gives short run times Traditional GC-MS typically requires a fair amount of time for a sample to be diluted, possibly filtered, and then run on a GC-MS. There are various modern techniques of rapidly introducing samples into a mass spectrometer, such as DESI desorption electrospray ionisation, DART direct analysis in real time and DSA...
The NanoLockSpray™ dual electrospray ion source accessory with optimized co-introduction of analyte and lock mass compounds provides authenticated exact mass measurement in NanoFlow™ LC/MS and LC/MS/MS modes of operation.
The researchers genetically engineered a strain of mice to make either Myc or another cancer-associated protein called Ras in the proximal tubules of the kidney when a compound called doxycycline, which had been added to their drinking water, was removed from it. (Myc and Ras are not normally produced at high levels by these cells.) Ras-producing mice did not get cancer. But within just a few weeks, the mice that made Myc developed kidney cancers that mimicked an aggressive subset of human renal cell adenocarcinoma that originates in the kidneys collecting ducts. Adding doxycycline back to the animals water caused the tumors to shrink dramatically.. The researchers then turned to a new tissue analysis technique called desorption electrospray ionization mass-spectrometric imaging, or DESI-MSI, recently developed by postdoctoral scholar Livia Eberlin, PhD, in the Zare laboratory to compare cancerous and normal tissue.. DESI-MSI creates a highly detailed, two-dimensional map of the chemical ...
A hybrid mass spectrometer comprises an ion mobility (IMS) section and a mass analysis section that analyses ions based on mass-to-charge ratios. In the IMS section, a DC potential gradient is established and a drift gas provided, so as to separate ions based on varying ion mobilities. Additionally, at least a downstream portion of the IMS section includes a rod set focusing ions along the axis, this prevents loss of ions and gives good transfer of ions into-a-mass analysis section, which can be a time-of-flight mass analyzer or an analyzer including a quadrupole rod set. A collision cell and mass analyzer can be provided between the two sections for MS/MS analysis. The IMS section then provides better utilization of an available sample; as each group of ions is elected from the IMS section, one ion can be mass selected as a precursor, for subsequent fragmentation/reaction and subsequent mass analysis of the product ions. Another aspect of the invention provides the ability to form potential wells,
Sprawdź ile zapłacisz za lek Cefobid pharmacy bulk package - not for direct infusion w aptece, znajdź tańsze zamienniki leku. Określ swoje uprawnienia i sprawdź jakie zniżki Ci przysługują.
Super-atmospheric pressure ionization mass spectrometry and its application to ultrafast online protein digestion analysis Journal of Mass Spectrometry , 2016, 51 , 396-411 Lee Chuin Chen, Satoshi Ninomiya and Kenzo Hiraoka Abstract Ion source pressure plays a significant role in the process of ionization and the subsequent ion transmission inside...
A method for screening newborns using electrospray tandem mass spectrometry. The method improves the current protocols that use tandem mass spectrometry by assuring accurate and consistent results at the clinical level through enhanced quality controls and quality assurance protocols as applied to the scan profiling and sample preparation of blood spots from newborns. Specific additives are used in precise concentrations of internal standards, employing detailed controls adapted to distinguish twenty metabolites, which are scanned and vigorously compared to known spectra results. Revealing peaks, metabolite concentration, and scan intensities in the quality assurance steps are then compared to a range of thresholds to determine whether or not the sample is contaminated, drug-ridden, diagnosable, or unacceptable. All spectra results and quality assurance flags are organized in spreadsheet form and exported to a database where values are compiled and stored for daily output results and trend analysis. The
Practically, all types of rockbursts are accompanied by release of seismic energy, rock bulking (due to fracturing and fragmentation), and ejection of fragmented rocks in the opening. Principles of...
Mass spectrometry (MS) analysis was performed as described previously [11]. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels containing the proteins of interest were excised, destained with 50% acetonitrile in 0.1 M ammonium bicarbonate, and dried in a SpeedVac evaporator. Dried gel pieces were re-swollen with 30 μL 25 mM sodium bicarbonate, pH 8.8, containing 50 ng trypsin (Promega, Madison, WI, USA) at 37°C overnight. Samples were desalted using Zip-Tips C18 (Millipore, Bedford, MA, USA) and dissolved in 10 μL 2% acetonitrile in 0.1% formic acid. MS analysis was performed using a LTQ XL linear ion trap mass spectrometer system (Thermo Fisher Scientific, San Jose, CA, USA) at the Proteomics Core, National Cancer Center, Korea. The mass spectrometer was set for nanospray ionization (NSI) in positive mode. A syringe pump was used to introduce the calibration solution for automatic tuning and calibration of the LTQ in NSI positive ion mode. Infusion of digested samples ...
Interpreting Protein Mass Spectra is a hands-on laboratory guide for a wide range of researchers investigating the structures of proteins and peptides. The focus is on the interpretation of structural information gathered through electrospray ionization-mass spectrometry (ESI-MS).
EthR binds to DNA, so rather than look for direct binding of fragments to EthR the researchers instead looked for fragments that could disrupt the EthR-DNA complex. A small library of 73 fragments was tested (at 0.5 mM each, in 2% DMSO), yielding 8 hits. The same library was screened under the same conditions using differential scanning fluorimetry (DSF), yielding 7 hits, 4 of which had also been identified using ESI-MS. All 11 of these molecules were then tested under the same conditions in an SPR assay to see if they could disrupt the interaction between EthR and chip-bound DNA. The 7 best SPR hits were all fragments that had been identified by ESI-MS. Moreover, two fragments - one identified solely by ESI-MS and one identified by both ESI-MS and DSF - were characterized bound to EthR crystallographically, and these represent new chemotypes for this target ...
Based on http://somatolinecosmeticavis.review data. Significantly simplified work flows were developed for rapid analysis of various types of cosmetic and foodstuff samples by employing a miniature mass spectrometry system and ambient ionization methods. A desktop Mini 12 ion trap mass spectrometer was coupled with paper spray ionization, extraction spray ionization and slug-flow microextraction for direct analysis of Sudan Reds, parabens, antibiotics, steroids, bisphenol and plasticizer from raw samples with complex matrices. Limits of detection as low as 5 μg/kg were obtained for target analytes. On-line derivatization was also implemented for analysis of steroid in cosmetics. The developed methods provide potential analytical possibility for outside-the-lab screening of cosmetics and foodstuff products for the presence of illegal substances.. An analytical method was developed for the identification and quantification of seven volatile n-nitrosamines (n-nitrosodimethylamine [NDMA], ...
Aminoglycoside (AMG) residues are extracted from tissue using buffer containing trichloroacetic acid as a protein precipitant. The extract is neutralized prior to solid-phase extraction (SPE) clean-up with a weak cation exchange cartridge followed by elution with acidic methanol. The methanolic extract is evaporated and reconstituted in an aqueous ion-pair reagent followed by ion-pair reversed-phase liquid chromatography with detection by electrospray ion trap mass spectrometry. Confirmation is accomplished by comparison of retention time and full or partial scan MS/MS spectra with those of a fortified tissue standard and external standard respectively. ...
Improved middle-down characterization of antibodies using multiple ion activation techniques and Proton Transfer Reaction on a modified Orbitrap mass spectrometer Romain Huguet. MP 676, Poster Session 10.30 AM - 2.30 PM. FabRICATOR® and GingisKHAN®. Direct Determination of Antibody Chain Pairing by Top-Down Mass Spectrometry using Electron Capture Dissociation and Ultraviolet Photodissociation Jared Shaw. Room B302-305, Oral Presentation 3.50 PM - 4.10 PM. FabRICATOR® and GingisKHAN®. Unraveling a complex immunoprotein profile in multiple myeloma with middle-down de novo sequencing and native mass spectrometry Valerie J Winton. Room A411-412, Oral Presentation 9.30 AM - 9.50 AM. FabRICATOR®. Middle Down Approach for the Characterization of Monoclonal Antibodies After Ides Digestion and ETD Fragmentation. Colin Wynne. MP 782, Poster Session 10.30 AM - 2.30 PM. FabRICATOR®. ...
Latest webinar from Thermo Scientific Increased yield from novel nano-electrospray workflows in LC-MS based proteomics Register now Tuesday,160September 18, 2012 1500 UTC 0800 PT 1100 ET 1600 UK 1700 CET Click here to check the time in your own country Nano-electrospray is widely used in proteomics for its high sensitivity but its also...
Mass spectrometry data analysis is specific to the type of experiment producing the data. General subdivisions of data are fundamental to understanding any data. Many mass spectrometers work in either negative ion mode or positive ion mode. It is very important to know whether the observed ions are negatively or positively charged. This is often important in determining the neutral mass but it also indicates something about the nature of the molecules. Different types of ion source result in different arrays of fragments produced from the original molecules. An electron ionization source produces many fragments and mostly single-charged (1-) radicals (odd number of electrons), whereas an electrospray source usually produces non-radical quasimolecular ions that are frequently multiply charged. Tandem mass spectrometry purposely produces fragment ions post-source and can drastically change the sort of data achieved by an experiment. Knowledge of the origin of a sample can provide insight into the ...
Lindholm et al. report the cloning, molecular characterization, and tissue expression of a member of a new family of neurotrophins. Through sequence analysis, they identified a gene similar to that encoding mesencephalic-astrocyte-derived neurotrophic factor (MANF, also known as ARMET) and named the new protein conserved dopamine neurotrophic factor (CDNF, which in genomic databases was called ARMETL1 for ARMET-like 1). CDNF was secreted when heterologously expressed in human cultured cell lines or the insect cell line Sf9. Electrospray ionization-mass spectrometry analysis of the secreted protein indicated that the protein formed four disulfide bridges with the eight conserved cysteines. Transcript analysis in mice revealed that CDNF was expressed in several tissues during embryogenesis and postnatally. In the brain, in situ protein analysis showed that the protein was present in the somas of neurons. Although MANF was previously reported to promote survival of dopaminergic neurons in vitro, ...
Author: Michalski, Annette et al.; Genre: Journal Article; Published in Print: 2012-11; Keywords: COLLISION-INDUCED DISSOCIATION; TANDEM MASS-SPECTRA; PROTONATED|br/| PEPTIDES; ION-TRAP; HIGH-RESOLUTION; FRAGMENTATION PATHWAYS; SEQUENCE|br/| INFORMATION; C-TRAP; SPECTROMETRY; PROTEOMICStandem mass spectrometry; fragmentation mechanisms; shotgun proteomics;|br/| ion types; CID; HCD; Expert System; spectrum annotation; ; Title: A Systematic Investigation into the Nature of Tryptic HCD Spectra
adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A ...
State-specific ionization efficiencies for excited Li and Na atoms in acetylene/air flames have been determined. The ionization efficiencies, i.e., the probability that the excited atoms ionize instead of returning to the ground state, are determined by relating collision-assisted Laser-Enhanced Ionization (LEI) signals from various excited states with laser-induced photoionization signals. The ionization efficiencies are found to decrease (from being one at the ionization limit) almost monotonically as the lower atoms are excited. The most striking feature, however, is that the decrease of the ionization efficiency values is generally found to be less than the decrease of the Boltzmann factor, exp(-Δ,i,E/kT,/i,), when the energy difference, Δ,i,E,,/i, between the excited state and the ionization limit is increased. The ionization efficiencies are found to be close to unity for states with Δ,i,E,/i, , ,i,kT,/i, and approximately 50% for states with Δ,i,E,/i, ≈ 2.5 ,i,kT,/i, (,i,np,/i, ≈ ...