Development of Analytical Methods for Nitrated Polycyclic Aromatic Compounds and Nitrated Peptides Using a Combination of Electrospray Mass Spectrometry, Microbore High Performance Liquid Chromatography and Matrix Assisted Laser Desorption/ionization Mass Spectrometry PDF Download
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Author: Tamika Terrilyn Jasmine Williams
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
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Book Description
Author: Tamika Terrilyn Jasmine Williams
Publisher:
ISBN:
Category :
Languages : en
Pages : 208
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 233
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Book Description
The development of matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) gave rise to the era of biological mass spectrometry and the new field of proteomics. Two recurring problems that are central to advancing the science of proteomics are the development of reliable mass spectrometry methods to identify proteins and to sequence peptides. The specificity of proteases such as trypsin in combination with the high mass accuracy provided by reflectron time-of-flight mass analyzers, allows the reliable identification of a protein from the mass spectrum of its proteolytic digestion products in an experiment known as peptide mass fingerprinting. Some powerful approaches to improve the confidence of the identification of proteins in the peptide mass fingerprinting experiment have been described in this dissertation. Both approaches described in this dissertation involve the optimization of different aspects of the sample preparation step in the MALDI-TOF mass spectrometry experiment. Precursor-ion scanning in the negative ion mode followed by sequencing in the positive ion mode is a powerful strategy employed to identify and sequence phosphopeptides via nanoelectrospray triple quadrupole mass spectrometry. Less sample and time would be consumed if both of the aforementioned steps could be carried out in the negative ion mode. Nanoelectrospray tandem mass spectrometry in the negative ion mode is usually not successful as traditional gold-coated emitters undergo electrical discharge. Using polyaniline-coated emitters, we have demonstrated that peptides can be sequenced successfully in the negative-ion mode enabling the observation of a wealth of information that is not available in the corresponding positive-ion mode experiment.
Author: Richard B. Cole
Publisher: Wiley-Interscience
ISBN:
Category : Science
Languages : en
Pages : 610
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Book Description
Comprehensive, up-to-date coverage of a revolutionary technique Electrospray ionization mass spectrometry (ESI-MS) has completely changed the way physicists, chemists, and biologists view the study of large molecules. The technique derives detailed information about molecular weights and structures from extremely small sample quantities. ESI-MS can create highly charged forms of very high molecular weight compounds, it is naturally compatible with many types of separation techniques, and it allows noncovalent interactions between molecules in solution to be preserved in the gas phase. But many researchers may not use the technique to its full potential because they are unfamiliar with the different perspectives of its underlying processes, the varied approaches to implementation, and the wide-ranging utility of the technique. In this book, Richard B. Cole and an assemblage of leading researchers present a single-volume compilation of different approaches to the understanding and exploitation of ESI-MS. This comprehensive guide: * Examines the physical and chemical aspects of the electrospray process and describes the events involved in ion formation as well as the electro-chemical phenomena that are central to charged droplet formation during the process * Explores the coupling of electrospray ionization to various mass spectrometers, including quadrupole, magnetic, time-of-flight, quadrupole ion trap, and Fourier transform ion cyclotron resonance instruments * Describes recent progress in interfacing ESI with solution-based separation techniques, including liquid chromatography and capillary electrophoresis * Charts the rapid development of ESI applications and categorizes them by compound type: peptides and proteins, nucleic acids and their constituents, carbohydrates and lipids, small molecules related to pharmacology and drug metabolism, and organometallics and inorganic compounds Electrospray Ionization Mass Spectrometry is the indispensable handbook and reference for anyone who wishes to understand, implement, or apply this technique, including researchers in chemistry, metallochemistry, biochemistry, biology, pharmacology, and physics.
Author: Minna Hakkarainen
Publisher: Springer Science & Business Media
ISBN: 3642280404
Category : Technology & Engineering
Languages : en
Pages : 219
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Book Description
Emerging Mass Spectrometric Tools for Analysis of Polymers and Polymer Additives, by Nina Aminlashgari and Minna Hakkarainen. Analysis of Polymer Additives and Impurities by Liquid Chromatography/Mass Spectrometry and Capillary Electrophoresis/Mass Spectrometry, by Wolfgang Buchberger and Martin Stiftinger. Direct Insertion Probe Mass Spectrometry of Polymers, by Jale Hacaloglu Mass Spectrometric Characterization of Oligo- and Polysaccharides and Their Derivatives, by Petra Mischnick. Electrospray Ionization-Mass Spectrometry for Molecular Level Understanding of Polymer Degradation, by Minna Hakkarainen.
Author: Nnenna Dieke
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 0
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Ionization of peptides is an important step in mass spectrometry (MS)-based bottom-up proteomics. Electrospray ionization (ESI) is a common method of converting peptide ions into the gas phase. ESI is known to produce multiply protonated ions, [M + nH]n+. The addition of trivalent chromium, Cr(III), to peptide solutions undergoing ESI was discovered to increase the protonation of peptides. This dissertation contains fundamental studies of peptide ionization using trivalent chromium, Cr(III), as an additive.Experimental studies were completed to deduce the mechanism of Cr(III) enhanced protonation in ESI. Cr(III) enhances the protonation of model peptides with an acidic residue at the C-terminus to a greater extent than when the acidic residue is further away. The protonation of model peptide amides containing no carboxyl groups at the C-terminus or sidechain are enhanced by the addition of Cr(III). This indicates that carboxyl and amide groups are involved in the mechanism. Enhanced protonation with Cr(III) was ineffective with phosphorylated peptides and contributed to a pH effect in proteins.A survey of twenty-seven biological peptides was completed to gauge the analytical utility of Cr(III) in MS-based proteomics. Not all peptides underwent enhanced protonation by ESI upon addition of Cr(III), but Cr(III) did enhance the protonation of eleven peptides by adding an additional proton or increasing the signal intensity. Compared to model peptides, the interactions between sidechains of biological peptides are of higher complexity and can prevent the binding and/or dissociation of Cr(III) from the peptide.Different methods of delivering Cr(III) into the ESI source region were attempted to incorporate Cr(III) in MS-based proteomic workflows. Post-column addition of Cr(III) is possible using a tee union to introduce the Cr(III) solution or by doping the nebulizing gas with Cr(III). This signifies that Cr(III) does not have to be added to peptide solutions but can be introduced with the nebulizing gas during desolvation or as a separate solution into the ESI source bypassing chromatography. Dissociation of protonated ions formed by Cr(III) were also studied. The electron transfer dissociation (ETD) products of precursor ions generated upon addition of Cr(III) did not differ from those of precursor ions generated using 1% acetic acid. Higher charge states (n) generate better sequence coverage than [M + 2H]2+. Certain residues (i.e., proline, basic, and acid residues) direct fragmentation and the type of product ions produced in ETD. This residue effect is more prevalent with [M + 2H]2+ and subsides with higher charge states. Matrix-assisted laser desorption ionization (MALDI) is another method of ionizing peptides. Singly protonated ions, [M +H]+, are generally formed in MALDI. Additional protons are not expected to be added with Cr(III), but rather an increase in the intensity of [M + H]+. Although some promising results were obtained, the effect of Cr(III) as an additive in MALDI analysis of peptides was inconclusive due to poor reproducibility, which is common in MALDI.
Author: Wonhyeuk Jung
Publisher:
ISBN:
Category :
Languages : en
Pages : 160
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Book Description
Native mass spectrometry (MS) is a branch of MS analysis in which the structure of the target analytes of interest are kept intact and remaining in their "native" functional structure (as much as possible). This approach was made possible by the development of electrospray ionization (ESI), a soft ionization technique that does not fragment the target analyte during the ionization process while inducing multiple charging. The multiply charged biomolecules, in turn, can be subjected to fragmentation via collisional activation with a non-reactive gas such as nitrogen. This approach of combining native MS with fragmentation-based analysis, termed native topdown MS analysis, can be applied to large biomolecules such as membrane proteins to gain structural insights. Membrane proteins present unique challenges to conventional high-resolution structural techniques due to their hydrophobic nature. However, they are responsible for various physiological phenomena and account for 60% of known druggable targets in the cell. Thus, there is a need for an approach that can overcome issues with membrane protein analysis while complementing other biophysical techniques used to probe protein structure. Here, how native top-down MS can play this role is presented. The effects of non-ionic saccharide-based detergents, a commonly used class of detergents for membrane protein solubilization, on the resulting charge states of soluble proteins is investigated to gain insights into the mechanism of ESI. The MS-fragmentation patterns from collisionally activated dissociation of membrane proteins and membrane protein-lipid complexes are compared. How new insights into the lipid binding sites can be gained by detecting lipid-bound MS-fragments is presented. The result of the study indicates that native top-down MS analysis can provide unique structural insights for membrane proteins and their non-covalent interactions. When the analytical goal is to investigate the atomic composition of the target analyte, an ionization approach in which the sample is fully atomized before MS analysis is preferred instead. Inductively coupled plasma ionization, which atomizes and ionizes the sample via a plasma, can be coupled with MS analysis (ICP-MS) to quantify heavy metal contamination in complex samples. A protocol for ICP-MS analysis of commercial fish products for mercury contamination detection developed to aid an analytical chemistry class for instruction of undergraduate chemistry students is presented.
Author: TPE. Hollenbeck
Publisher:
ISBN:
Category : Condoms
Languages : en
Pages : 6
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Book Description
Electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry have been used to examine evidence in a sexual assault investigation. Because condoms are being used increasingly by sexual assailants and some condom brands include the spermicide nonoxynol-9 (nonylphenoxy polyethoxyethanol) in the lubricant formulation, the recovery, and identification of nonoxynol-9 from evidence items may assist in proving corpus delicti. A method was developed for the recovery of nonoxynol-9 from internal vaginal swabs and for its identification by reverse phase liquid chromatography/electrospray ionization mass spectrometry (LC ESI-MS), nanoelectrospray ionization (nanoESI) mass spectrometry, and high resolution MALDI Fourier transform mass spectrometry (MALDI-FTMS) The method was tested on extracts from precoitus, immediate postcoitus, and four-hours postcoitus vaginal swabs provided by a volunteer whose partner does not normally use condoms, but for this trial used a condom having a water-soluble gel-type lubricant that includes 5% nonoxynol-9 in its formulation. Subsequently, LC ESI-MS was used to identify traces of nonoxynol-9 from the internal vaginal swab of a victim of a sexual assault.
Author: Nikolaus H. Fischer
Publisher: Springer Science & Business Media
ISBN: 1468490605
Category : Science
Languages : en
Pages : 412
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Book Description
This volume contains reviews which are based on a symposium, given th at the 30 meeting of The Phytochemical Society of North America, held at Laval University in Quebec City, Canada on August 11-15, 1990. During the past two decades, there have been major new developments in methods which can be applied toward the isolation, separation and structure determination of complex natural products. Therefore, the topic of this symposium, "Modem Phytochemical Methods", is a very timely one. The organizers of the symposium recognized that it would not be possible to cover in detail all new advances in phytochemical methodology. It was therefore decided to emphasize general reviews on recent developments of major separation techniques such as high performance liquid chromatography as well as supercritical fluid chromato graphy. In addition, advances in commonly used structure determination methods, mainly NMR and MS, are reviewed. Other topics include methodo logies of micro-sampling for isolation and analysis of trichome constituents as well as recent breakthroughs on biosynthetic studies of monoterpenes using "enriched" basal cells of trichomes. The volume concludes with a review of quantitative structure-activity relationship (QSAR) studies of biologically active natural products. In Chapter I, K. Hostettmann and his colleagues give a general review of recent developments in the separation of natural products with major emphasis on preparative separations of biologically active plant constituents. The authors present a comparison of droplet countercurrent chromatography (OCCC) with the highly rapid and more versatile centrifugal partition chromatography (CPC).
Author: Thomas S. Bianchi
Publisher: Princeton University Press
ISBN: 1400839106
Category : Science
Languages : en
Pages : 417
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Book Description
This textbook provides a unique and thorough look at the application of chemical biomarkers to aquatic ecosystems. Defining a chemical biomarker as a compound that can be linked to particular sources of organic matter identified in the sediment record, the book indicates that the application of these biomarkers for an understanding of aquatic ecosystems consists of a biogeochemical approach that has been quite successful but underused. This book offers a wide-ranging guide to the broad diversity of these chemical biomarkers, is the first to be structured around the compounds themselves, and examines them in a connected and comprehensive way. This timely book is appropriate for advanced undergraduate and graduate students seeking training in this area; researchers in biochemistry, organic geochemistry, and biogeochemistry; researchers working on aspects of organic cycling in aquatic ecosystems; and paleoceanographers, petroleum geologists, and ecologists. Provides a guide to the broad diversity of chemical biomarkers in aquatic environments The first textbook to be structured around the compounds themselves Describes the structure, biochemical synthesis, analysis, and reactivity of each class of biomarkers Offers a selection of relevant applications to aquatic systems, including lakes, rivers, estuaries, oceans, and paleoenvironments Demonstrates the utility of using organic molecules as tracers of processes occurring in aquatic ecosystems, both modern and ancient
Author: Leo M.L. Nollet
Publisher: CRC Press
ISBN: 1482297841
Category : Science
Languages : en
Pages : 1530
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Book Description
Updated to reflect changes in the industry during the last ten years, The Handbook of Food Analysis, Third Edition covers the new analysis systems, optimization of existing techniques, and automation and miniaturization methods. Under the editorial guidance of food science pioneer Leo M.L. Nollet and new editor Fidel Toldra, the chapters take an in
