Rozprawy doktorskie: „Fourier transform ion cyclotron resonance mass spectrometry”

1

Hauschild, Jennifer M. "Fourier transform ion cyclotron resonance mass spectrometry for petroleomics". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:8604a373-fb6b-4bc0-8dc1-464a191b1fac.

Pełny tekst źródła

Streszczenie:

The past two decades have witnessed tremendous advances in the field of high accuracy, high mass resolution data acquisition of complex samples such as crude oils and the human proteome. With the development of Fourier transform ion cyclotron resonance mass spectrometry, the rapidly growing field of petroleomics has emerged, whose goal is to process and analyse the large volumes of complex and often poorly understood data on crude oils generated by mass spectrometry. As global oil resources deplete, oil companies are increasingly moving towards the extraction and refining of the still plentiful reserves of heavy, carbon rich and highly contaminated crude oil. It is essential that the oil industry gather the maximum possible amount of information about the crude oil prior to setting up the drilling infrastructure, in order to reduce processing costs. This project describes how machine learning can be used as a novel way to extract critical information from complex mass spectra which will aid in the processing of crude oils. The thesis discusses the experimental methods involved in acquiring high accuracy mass spectral data for a large and key industry-standard set of crude oil samples. These data are subsequently analysed to identify possible links between the raw mass spectra and certain physical properties of the oils, such as pour point and sulphur content. Methods including artificial neural networks and self organising maps are described and the use of spectral clustering and pattern recognition to classify crude oils is investigated. The main focus of the research, the creation of an original simulated annealing genetic algorithm hybrid technique (SAGA), is discussed in detail and the successes of modelling a number of different datasets using all described methods are outlined. Despite the complexity of the underlying mass spectrometry data, which reflects the considerable chemical diversity of the samples themselves, the results show that physical properties can be modelled with varying degrees of success. When modelling pour point temperatures, the artificial neural network achieved an average prediction error of less than 10% while SAGA predicted the same values with an average accuracy of more than 85%. It did not prove possible to model any of the other properties with such statistical significance; however improvements to feature extraction and pre-processing of the spectral data as well as enhancement of the modelling techniques should yield more consistent and statistically reliable results. These should in due course lead to a comprehensive model which the oil industry can use to process crude oil data using rapid and cost effective analytical methods.

Style APA, Harvard, Vancouver, ISO itp.

2

Lin, Tzu-Yung. "Advanced electronics for Fourier-transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/55048/.

Pełny tekst źródła

Streszczenie:

With the development of mass spectrometry (MS) instruments starting in the late 19th century, more and more research emphasis has been put on MS related subjects, especially the instrumentation and its applications. Instrumentation research has led modern mass spectrometers into a new era where the MS performance, such as resolving power and mass accuracy, is close to its theoretical limit. Such advanced performance releases more opportunities for scientists to conduct analytical research that could not be performed before. This thesis reviews general MS history and some of the important milestones, followed by introductions to ion cyclotron resonance (ICR) technique and quadrupole operation. Existing electronic designs, such as Fourier-transform ion cyclotron resonance (FT-ICR) preamplifiers (for ion signal detection) and radio-frequency (RF) oscillators (for ion transportation/filtering) are reviewed. Then the potential scope for improvement is discussed. Two new FT-ICR preamplifiers are reported; both preamplifiers operate at room temperature. The first preamplifier uses an operational amplifier (op amp) in a transimpedance configuration. When a 18-k feedback resistor is used, this preamplifier delivers a transimpedance of about 85 dB , and an input current noise spectral density of around 1 pA/ p Hz. The total power consumption of this circuit is around 310 mW when tested on the bench. This preamplifier has a bandwidth of fi3 kHz to 10 MHz, which corresponds to the mass-to-charge ratio, m/z, of approximately 18 to 61k at 12 T for FT-ICR MS. The transimpedance and the bandwidth can be adjusted by replacing passive components such as the feedback resistor and capacitor. The feedback and bandwidth limitation of the circuit is also discussed. When using an 0402 type surface mount resistor, the maximum possible transimpedance, without sacrificing its bandwidth, is approximated to 5.3 M . Under this condition, the preamplifier is estimated to be able to detect ~110 charges. The second preamplifier employs a single-transistor design using a different feedback arrangement, a T-shaped feedback network. Such a feedback system allows ~100-fold less feedback resistance at a given transimpedance, hence preserving bandwidth, which is beneficial to applications demanding high gain. The single-transistor preamplifier yields a low power consumption of ~5.7 mW, and a transimpedance of 80 dB in the frequency range between 1 kHz and 1 MHz (m/z of around 180 to 180k for a 12-T FT-ICR system). In trading noise performance for higher transimpedance, an alternative preamplifier design has also been presented with a transimpedance of 120 dB in the same frequency range. The previously reported room-temperature FT-ICR preamplifier had a voltage gain of about 25, a bandwidth of around 1 MHz when bench tested, and a voltage noise spectral density of ~7.4 nV/ p Hz. The bandwidth performance when connecting this preamplifier to an ICR cell has not been reported. However, from the transimpedance theory, the transimpedance preamplifiers reported in this work will have a bandwidth wider by a factor of the open-loop gain of the amplifier. In a separate development, an oscillator is proposed as a power supply for a quadrupole mass filter in a mass spectrometer system. It targets a stabilized output frequency, and a feedback control for output amplitude stabilization. The newly designed circuit has a very stable output frequency at 1 MHz, with a frequency tolerance of 15 ppm specified by the crystal oscillator datasheet. Within this circuit, an automatic gain control (AGC) unit is built for output amplitude stabilisation. A new transformer design is also proposed. The dimension of the quadrupole being used as a mass filter will be determined in the future. This circuit (in particular the transformer and the quadrupole connection/mounting device) will be finalised after the design of the quadrupole. Finally, this thesis concludes with a discussion between the gain and the noise performance of an FT-ICR preamplifier. A brief analysis about the correlation between the gain, cyclotron frequency, and input capacitance is performed. Future work is also suggested for extending this research.

Style APA, Harvard, Vancouver, ISO itp.

3

Qi, Yulin. "Advanced methods in Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57931/.

Pełny tekst źródła

Streszczenie:

Mass spectrometry (MS) is a powerful analytical technique used to characterize various compounds by measuring the mass-to-charge ratio (m/z). Among different types of mass analyzers, Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) is the instrument of choice for those working at the forefront of research, as it offers incomparable mass accuracy, resolving power, and the highest flexibility for hybrid instrumentation and fragmentation techniques. The FT-ICR MS requires professional and careful tuning to achieve its superior performance. Our work aims to review, develop and apply advanced methods to improve the data quality of FT-ICR and push the limits of the instrument. FT-ICR spectrometry has been limited to the magnitude-mode for 40 years due to the complexity of the phase-wrapping problem. However, it is well known that by correcting phase of the data, the spectrum can be plotted in the absorption-mode with a mass resolving power that is as much as two times higher than conventional magnitude-mode. Based on the assumption that the frequency sweep excitation produces a quadratic accumulation in an ion’s phase value, a robust manual method to correct all ions’ phase shifts has been developed, which allows a broadband FT-ICR spectrum to be plotted in the absorption-mode. The developed phasing method has then been applied to a large variety of samples (peptides, proteins, crude oil), different spectral acquisition-mode (broadband, narrowband), and different design of ICR cells (Infinity cell, ParaCell) to compare the performance with the conventional magnitude-mode spectra. The outcome shows that, by plotting the absorption-mode spectrum, not only is the spectral quality improved at no extra cost, but the number of detectable peaks is also increased. Additionally, it has been found that artifactual peaks, such as noise or harmonics in the spectrum can be diagnosed immediately in the absorption-mode. Given the improved characteristics of the absorption-mode spectrum, the following research was then focused on a data processing procedure for phase correction and the features of the phase function. The results demonstrate that in the vast majority of cases, the phase function needs to be calculated just once, whenever the instrument is calibrated. In addition, an internal calibration method for calculating the phase function of spectra with insufficient peak density across the whole mass range has been developed. The above research is the basis of the Autophaser program which allows spectra recorded on any FT-ICR MS to be phase corrected in an automated manner.

Style APA, Harvard, Vancouver, ISO itp.

4

Mullen, Steven Lawrence. "Fourier transform ion cyclotron resonance mass spectrometry of organometallic compounds /". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487325740718905.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

5

Weisbrod, Chad Randal. "Improvement of Fourier transform ion cyclotron resonance mass spectrometry detection technology". Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/c_weisbrod_060210.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

6

Gates, Paul Jonathan. "Fourier-transform ion cyclotron resonance mass spectrometry : analysis of natural products". Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621612.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Wills, Rebecca Helen. "High mass accuracy analytical applications of Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/60050/.

Pełny tekst źródła

Streszczenie:

The performance capabilities of Fourier transform ion cyclotron resonance (FTICR) mass spectrometry are higher than any other type of mass spectrometer, making this technique suitable for a range of analytical applications. Here, FTICR mass spectrometry has been used for the structural analysis of polyketides and nonribosomal peptides, and in the identification of peptide binding sites of ruthenium(II) arene anticancer complexes. In both these applications, methods have been developed involving complementary tandem mass spectrometry techniques, specifically collision activated dissociation (CAD), electron induced dissociation (EID), and electron capture dissociation. In particular, CAD and EID have been shown to be effective in the structural characterisation of polyketides, with a method developed for distinguishing between two isomers of the polyketide lasalocid A. This method has been optimised and extended for application to non-ribosomal peptides enabling detailed structural information to be obtained with very high accuracy. Using CAD and ECD has enabled the identification of amino acids involved in binding ruthenium(II) complexes. Binding to phenylalanine and glutamic acid was observed in this work for the first time; coordination by histidine and methionine was also observed and is in agreement with previous work. Overall, new methods for highly accurate structural characterisation and binding site identification have been successfully designed and implemented.

Style APA, Harvard, Vancouver, ISO itp.

8

Schmidt, Eric Grayson. "Observation and control of ion motion in fourier transform ion cyclotron resonance mass spectrometry /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

9

Tsybin, Youri. "High Rate Electron Capture Dissociation Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". Doctoral thesis, Uppsala universitet, Jonfysik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4136.

Pełny tekst źródła

Streszczenie:

Advances in science and technology during the past decade have greatly enhanced the level of the structural investigation of macromolecules – peptides and proteins. Biological mass spectrometry has become one of the most precise and sensitive techniques in peptide and protein analysis. However, increasing demands of biotechnological applications require further progress to be made. In the present thesis the development and improvement of peptide and protein characterization methods and techniques based on ion-electron and ion-photon reactions in electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry are described. The focus is on the development of the electron capture dissociation method, recently discovered by the group of professor McLafferty, into a high rate, efficient tandem mass spectrometrical technique. The rate and reliability of the electron capture dissociation technique were greatly increased by implementation of low-energy pencil electron beam injection systems based on indirectly heated dispenser cathodes. Further implementation of a hollow electron beam injection system combined, in a single experimental configuration, two rapid fragmentation techniques, high rate electron capture dissociation and infrared multiphoton dissociation. Simultaneous and consecutive irradiations of trapped ions with electrons and photons extended the possibilities for ion activation/dissociation reaction schemes and lead to improved peptide and protein characterization. Using these improvements, high rate electron capture dissociation was employed in time-limited experiments, such as liquid chromatography–tandem mass spectrometry and capillary electrophoresis-tandem mass spectrometry. The analytical applications of the developed techniques have been demonstrated in top-down sequencing of peptides and proteins up to 29 kDa, improved sequencing of peptides with multiple disulfide bridges and secondary fragmentation (w-ion formation), as well as extended characterization of peptide mixtures separated by liquid chromatography and capillary electrophoresis. For instance, the dissociation of peptides resulting from enzymatic digestion of proteins provided complementary structural information on peptides and proteins, as well as their post-translational modifications.

Style APA, Harvard, Vancouver, ISO itp.

10

Anupriya, Anupriya. "Gas Phase Structure Characterization Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6447.

Pełny tekst źródła

Streszczenie:

This dissertation investigates Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) based techniques to study the impact of molecular structure on conformation and binding energetics. A novel method to determine collison cross sectional areas using FTICR (CRAFTI), initially developed by the Dearden lab, was applied to study the conformations of molecular systems with unique structural attributes in an attempt to explore the molecular range of CRAFTI. The systems chosen for CRAFTI studies include crown-ether alkylammonium complexes and biogenic amino acids. The results were found to be consistent with expected behavior, and strongly correlated with experimental measurements made using ion mobility spectrometry (IMS) and predictions from computations. The analytical sensitivity of CRAFTI was highlighted by its ability to distinguish the normal and branched structural isomers of butylamine. Besides conformation characterization, quantitative evaluation of binding was undertaken on metal ion-cryptand complexes on the FTICR instrument using sustained off-resonance irradiation-collision-induced dissociation (SORI CID) method. Complex formation and dissociation was found to be a strong function of both guest and host sizes which impacted steric selectivity, and polarizability. The results demonstrate the ability of FTICR to simultaneously determine structure, conformation and binding thereby providing comprehensive molecular characterization.

Style APA, Harvard, Vancouver, ISO itp.

11

Wei, Juan. "Advanced applications of high performance Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/66290/.

Pełny tekst źródła

Streszczenie:

Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) displays its advances in obtaining high resolving power, high mass accuracy, and coupling with many different tandem mass spectrometry (MS/MS) techniques. In this thesis, the superior performance of FTICR MS was demonstrated by several different applications. The peak separation limit of the 12 T solariX FTICR instrument was challenged by measuring the isotopic fine structures of several 17O enriched amyloid-β (Aβ) peptides (Chapter 2 and 3). A resolving power as high as 6 M was achieved at m/z 880, and peaks were assigned with mass uncertainty less than 70 ppb. The accurate measurement of 17O labelling ratio is of value for estimating atomic distances by NMR experiments. Furthermore high mass accuracy and high resolution are proved vital for the confident assignment of peaks in a polymeric mixture due to the sample complexity and coexistence of different adducts (Chapter 4). On the other hand, one or more of the MS/MS techniques, collisionally activated dissociation (CAD), electron induced dissociation (EID), electron capture dissociation (ECD), and infrared multiphoton dissociation (IRMPD), were used to characterize the structures of chlorophyll-a (Chapter 6), pheophytin-a (Chapter 7), and d-α-tocopheryl polyethylene glycol succinate (TPGS), repectively, and diagnostic fragments are useful for their structural identification in the future. IRMPD was particularly efficient in fragmenting chlorophyll-a and pheophytin-a compared to EID and CAD. Based on the fragmentation pattern of TPGS attached with two different adducts (Li+, Na+, K+, Ag+, and H+), investigating the influence of adducts in ECD and CAD processes are of benefit for understanding the fragmentation mechanisms when cation adducts are involved (Chapter 5). In an on-going project, FTICR also displays the capability to study intact proteins above 30 kDa (Chapter 8).

Style APA, Harvard, Vancouver, ISO itp.

12

Williams, Christopher Paul. "Application of Hartley and Hilbert transforms in Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487760357822985.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

13

Ross, Charles William. "Gas phase ion - molecule reactions studied by Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487846885778077.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Shomo, Ronald Edward II. "Soft ionization techniques for Fourier transform ion cyclotron resonance and quadrupole mass spectrometry /". The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487597424138083.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

15

Grosshans, Peter Byron. "Improvements in our basic understanding of Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683756126656.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

16

Limbach, Patrick Alan. "Improvements to the analytical capabilities of fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487780393267365.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

17

Wood, Troy Dale. "Laser desorption Fourier transform ion cyclotron resonance (LD/FT/ICR) mass spectrometry for high mass ions /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu148784730905092.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

18

Wang, Mingda. "New and improved ion traps for high resolution Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487681788254101.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

19

Chen, Ruidan. "Theory and practice of ion trap design in fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847309053468.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

20

Torres, Theresa Ann. "Development of Fourier transform ion cyclotron resonance mass spectrometry for the study of ion-ion reactions /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

21

Marto, Jarrod A. "External Ion Injection and Applications of Ion Axialization in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry /". The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487868114113087.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

22

Craig, Edward Clayton. "Application of dispersion versus absorption (DISPA) in Fourier transform nuclear magnetic resonance and Fourier transform ion cyclotron mass spectrometry /". The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487324944214076.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

23

McDonnell, Liam Andrew. "Characterisation of macromolecules using electrospray ionization and Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2001. http://wrap.warwick.ac.uk/67794/.

Pełny tekst źródła

Streszczenie:

Multipole storage-assisted dissociation (MSAD), in which ions are stored for extended periods of time in a multipole ion-trap, represents one of the most recent and simplest methods by which structurally informative fragments can be obtained. A potential array investigation of MSAD is reported. It was found that the average kinetic energy of the ion was similar to the energy of a single IR photon and the average kinetic energy of an ion during sustained off-resonance irradiation collision-induced dissociation (SORICID), thus explaining the similar fragments that have been obtained using these techniques. The ion's average kinetic energy and its collision frequency was investigated as a function of the ion's charge, mass and mean free path, the space charge present in the hexapole ion trap and the applied radio frequency (RF) potential. All but one of the dependencies, namely the RF potential dependence, were in agreement with experimental results. The disagreement between the experimental results and the simulation results was due to the rate of charge accumulation depending on the applied RF potential. Without prior isolation, MSAD is limited in that it does not permit the isolation of a parent ion and the detection of all fragment ions. Collision-induced dissociation (CID) inside a Fourier transform ion cyclotron resonance (FTICR) cell permits the isolation, fragmentation and detection of all daughter ions. Furthermore the inherent advantages ofFTICR mass spectrometry, higher resolution and mass accuracy, are also afforded to the fragment ions as well as the initial parent ions. Using this technique, all of the components of a commercially available polymeric dye were assigned and the more intense components structurally characterised. This structural characterization highlighted new information regarding the low-energy multiple collision CID of substituted polyesters. Included in these findings was the charge-induced nature of the 1,4-H rearrangement, the participation of amino groups in the fragmentation mechanisms the collisional ring opening of a cyclic polymer. The two previous techniques involve collisions with neutral atoms to increase the internal energy (vibrational) of the ion to obtain the structurally informative fragments. In a similar manner, the fragments obtained after electronic excitation provide a powerful tool with which the electronic structure of molecules can be studied. An ion imaging study of HCI (2+ 1) resonance-enhanced multiphoton ionisation (REMPI) revealed new predissociation channels, an electronic-vibrational-rotational state dependence of the angular distribution of the fragments and vibrational state dependent HCI+ photodissociation. The additional predissociation channels continued the pseudoRydberg continuum of the superexcited states responsible for the previously detected predissociation channels. The complicated angular distribution behavior of the fragments is thought to reflect the diabatic state character of the resonant state, which then determines which superexcited states are accessible.

Style APA, Harvard, Vancouver, ISO itp.

24

Polfer, Nicolas Camille. "Structural elucidation of peptides and proteins by Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/11267.

Pełny tekst źródła

Streszczenie:

Two unique features of FT-ICR mass spectrometry are high mass resolution and mass accuracy. These features have been exploited in a novel approach to the study of metal exchange reactions in metallo-proteins using stable isotope labelling. The system chosen, Zn₄-SmtA, is a cyanobacterial metallothionein (MT) Deconvoluted ESI-FT-ICR spectra for Zn₄-FT-ICR spectra for Zn₄-Smt containing Zn isotopes in natural abundance as well as enriched with 93% ⁶⁷Zn show that the Zn₄ cluster of SmtA, in contrast to the structurally-analogous cluster of mammalian MT, contains a kinetically-inert Zn site, a feature which can be related to its secondary and tertiary structure, and which is of potential importance to its biological function. The main body of this work is a systematic study of the dissociation, via ECD, of doubly protonated peptides, such as luteinising hormone releasing hormone (LHRH), bradykinin and bombesin. The most common fragments reported in the literature occur from cleavage of the N-C₁₂ backbone bond, yielding c’ (N-terminal) and z’ (C-terminal) fragments. One striking observation in the spectra of the peptides studied is the presence of prominent radical c fragments (labelled herein c’) and even-electron z fragments (labelled z’). A study of the correlation between the relative abundance of each of the fragment ions as a function of the amino acid sequence for each of the peptides is shown. These experimental studies have been complemented molecular mechanics modelling, using the Amber force field, to correlate with putative gas-phase structures for these doubly protonated peptides. Here, a hypothesis is put forward that the relative ECD fragmentation pattern is related to the gas-phase structure of the peptide ion prior to electron capture, and in particular that hydrogen bonding of the protonated site to the backbone enhances backbone cleavage at that site (referred to as ‘ECD/structure correlation’). The relative ECD fragmentation pattern for bombesin and four LHRH variants are compared to their modelled gas-phase structures. A detailed study of the LHRH variants with sequence pEHWSYGLRPG-OH {1} and pEHWSYGLRPG-NH₂ {2}, and bombesin {3}, showed good agreement between the relative ECD fragment abundances and predicted Amber structures for {1} and {3}, but not for {2}. This may imply that the postulated model is not a full description of the ECD process.

Style APA, Harvard, Vancouver, ISO itp.

25

Green, Philip Spencer. "Biochemical applications of electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250112.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

26

May, Michael Alan. "Theoretical advances and laser desorption applications in Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487849377294552.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

27

Van, Orden Steven Lee. "Mechanistic investigations of gas phase ion-molecule reactions using Fourier transform ion cyclotron resonance mass spectrometry". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186137.

Pełny tekst źródła

Streszczenie:

Studies of the mechanisms and energetics of a variety ion-molecule reactions involving organometallic and organic ions, have been performed using Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The bond activation processes of V⁺, VO⁺, VOH⁺, and VOCH₃⁺ with water and methanol were investigated in detail. All ions are observed to preferentially activate the C-O bond in methanol, however C-H and O-H bond cleavage are also observed. The addition of the oxo, hydroxo, and methoxo ligands is found to significantly effect the intrinsic reactivity of the ions, relative to V⁺. The reactions of V(CO)₅⁻ with a wide variety of molecules have revealed mechanistic details of the oxidative addition and ligand switching reactions. Steric effects are proposed to account for the selective reactivity of V(CO)₅⁻ with alcohols and amines. Studies of ligand substitution reactions support an electron transfer initiated mechanism, implying that V(CO)₅⁻ has a triplet ground state and a trigonal bipyramidal structure. The chlorine atom transfer reactions of V(CO)₅⁻ with chloromethanes display a correlation with C-CI bond strength, suggesting the mechanism is initiated by oxidative addition of the C-C1 bond or involves a direct chlorine atom transfer. The decomposition of metallocarboxylate anions ([M(CO)ₓ₋₁CO₂]⁻) was studied in an effort to understand the production of CO₂ by metal carbonyl compounds, proposed as intermediates in the Water-Gas shift reaction. The nascent [M(CO)ₓ₋₁C0₂]⁻*, formed by nucleophilic addition of 0⁻ to M(CO)ₓ (M=Pe, Cr, V), is observed to undergo exclusive loss of CO₂ without subsequent decomposition of the product metal carbonyl anion (M(CO)ₓ₋₁⁻) The reaction of P AHs with O⁻ and O₂⁻ were studied, to investigate the potential of isomer differentiation by chemical ionization. These reactions are characterized by a number of reactive pathways, demonstrating the ability to distinguish isomers which cannot be differentiated by other ionization techniques. Kinetic energy release measurements of the S(N)2 reactions of F⁻ with CH3CI, C₆H₅CI, and CH₃COCl have been made using KEICR. The F⁻/CH₃Cl reaction results in a non-statistical energy disposal. The reaction is proposed to proceed by a direct mechanism.

Style APA, Harvard, Vancouver, ISO itp.

28

Kaiser, Nathan Kenneth. "Fourier transform ion cyclotron resonance mass spectrometry instrumentation design and development reduction of ion cloud de-phasing and time-of-flight discrimination /". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Fall2007/n_kaiser_120207.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

29

Ostrander, Chad Michael. "Development and evaluation of the central trapping electrode trapped-ion cell for Fourier transform mass spectrometry /". Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004351.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

30

Robinson, Jessica Marie. "Examination of gas-phase conformations of oligonucleotides using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

31

Benigni, Paolo. "Trapped Ion Mobility Spectrometry coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for the analysis of Complex Mixtures". FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3547.

Pełny tekst źródła

Streszczenie:

Analytical Characterization of complex mixtures, such as crude oil, environmental samples, and biological mixtures, is challenging because of the large diversity of molecular components. Mass spectrometry based techniques are among the most powerful tools for the separation of molecules based on their molecular composition, and the coupling of ion mobility spectrometry has enabled the separation and structural elucidation using the tridimensional structure of the molecule. The present work expands the ability of analytical chemists by furthering the development of IMS-MS instrumentation by coupling Trapped Ion Mobility Spectrometry to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (TIMS-FT-ICR MS). The TIMS-FT-ICR MS platform combines the high-resolution separation of TIMS, which has mobility resolving powers up to 400, and ultra-high mass resolution of FT-ICR MS, with mass resolving power over 1,000,000. This instrumentation allows the assignment of exact chemical composition for compounds in a complex mixture, as well as measurement of the collision cross-section of the molecule. Herein, the principles of the TIMS separation and its coupling to FT-ICR MS are described, as well as how the platform can be applied to targeted analysis of molecules, and untargeted characterization of complex mixtures. Molecular standards were analyzed by TIMS-MS in order to develop a computational workflow that can be utilized to elucidate molecular structure, using the measured collision cross-section of the ion. This workflow enabled identification of structural, cis/trans isomers, and chelated molecules and provides the basis for unsupervised structural elucidation of a complex mixture, and in particular for the elucidation of hydrocarbons from fossil fuels. In summary, this work presents the coupling of TIMS-FT-ICR MS and provides examples of applications as a proof of concept of the potential of this platform for solving complex analytical challenges.

Style APA, Harvard, Vancouver, ISO itp.

32

Hagman, Charlotte. "Method Development in Quantitative and Structural Proteomics using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4761.

Pełny tekst źródła

Streszczenie:

In this thesis, methods for studying different aspects of proteomics were developed with Fourier Transform Ion Cyclotron Resonance, (FTICR), mass spectrometry. The FTICR technique provides ultra-high mass resolving power, mass accuracy at sub ppm level and sensitivity in the attomole region.

Methods for quantifying biomarkers in body fluids such as cerebrospinal fluid, (CSF), and plasma were developed. Two sets of global markers with different properties were used for quantitative analysis; S-Methyl Thioacetimidate, (SMTA), and S-Methyl Thiopropionimidate, (SMTP), and [H₄]- and [D₄]-1-Nicotinoyloxy succinimide ester. Reduced ion suppression and higher sensitivity was obtained by coupling a High Performance Liquid Chromatography, (HPLC), system to the FTICR mass spectrometer.

In body fluids, proteins and peptides are present in a broad dynamic concentration range. Therefore, depleting abundant proteins prior to analysis results in decreased ion suppression and increased sensitivity. Two commercial depletion kits were evaluated with the SMTA- and SMTP-markers.

For both types of global markers, the experimental error for quantitative analysis of abundant proteins was less than 30%. This provides a lower limit for the protein up- and down regulations in complex solutions that can be monitored with HPLC-FTICR mass spectrometry.

Together with the identity and quantity of selected proteins the structure, dynamics and interactions with other molecules are of great importance. The later can be elucidated with Hydrogen/Deuterium Exchange, (HDX), mass spectrometry. Structural information at high resolution can be obtained with Collision-Induced Dissociation, (CID), HDX mass spectrometry. In this thesis, exchange rates of amide hydrogens in peptides were in excellent agreement with NMR results.

In some cases, the CID-fragments have different gas-phase exchange properties and as a consequence the solution phase exchange process can not be monitored. By applying Electron Capture Dissociation, (ECD), at ultra-high vacuum, the exchange process at a specific residue could be monitored.

Style APA, Harvard, Vancouver, ISO itp.

33

Ramström, Margareta. "Analysis of Complex Biological Samples using Liquid Chromatography-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". Doctoral thesis, Uppsala University, Analytical Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5729.

Pełny tekst źródła

Streszczenie:

Studies of protein and peptide expression are vital in order to understand complex biological systems. As demonstrated in this thesis, on-line packed capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS) is a useful analytical tool for such studies.

A proteomics method, based on global tryptic digestion and subsequent separation and detection of the peptides by LC-FTICR MS, was developed for qualitative analysis of body fluids. Initial experiments on cerebrospinal fluid (CSF) provided results that were comparable or superior to those achieved by more time- and sample-consuming techniques. The method was also successfully applied on plasma and amniotic fluid. One of the major challenges in proteomics is the broad dynamic range of proteins in biological matrices. The advantages of removing high-abundant components from CSF and plasma prior to MS were demonstrated.

In order to search for potential biomarkers, mass chromatograms of CSF from patients suffering from amyotrophic lateral sclerosis (ALS) and controls were compared using an in-house constructed pattern recognition program. ALS-specific patterns were observed, and four out of five unknown samples were correctly assigned. Alternative strategies to quantitatively compare two pools of samples rely on differential chemical labeling. The performance of one such method, quantification-using-enhanced-signal-tags, was investigated in complex sample analysis. The experimental intensity ratios were proven to be consistent with the prepared concentration ratios of abundant proteins in CSF.

Finally, the thesis reports on the first experiments where electron capture dissociation (ECD) was successfully incorporated in on-line LC-MS experiments. ECD and nozzle-skimmer fragmentation were applied to a sample of endocrine peptides extracted from mouse pancreatic islets. The two fragmentation methods provided complementary information. However, the method needs further optimization before it can be applied in the analysis of more complex samples, such as body fluids.

Style APA, Harvard, Vancouver, ISO itp.

34

Palmblad, Magnus. "Identification and Characterization of Peptides and Proteins using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". Doctoral thesis, Uppsala universitet, Institutionen för materialvetenskap, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1999.

Pełny tekst źródła

Streszczenie:

Mass spectrometry has in recent years been established as the standard method for protein identification and characterization in proteomics with excellent intrinsic sensitivity and specificity. Fourier transform ion cyclotron resonance is the mass spectrometric technique that provides the highest resolving power and mass accuracy, increasing the amount of information that can be obtained from complex samples. This thesis concerns how useful information on proteins of interest can be extracted from mass spectrometric data on different levels of protein structure and how to obtain this data experimentally. It was shown that it is possible to analyze complex mixtures of protein tryptic digests by direct infusion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and identify abundant proteins by peptide mass fingerprinting. Coupling on-line methods such as liquid chromatography and capillary electrophoresis increased the number of proteins that could be identified in human body fluids. Protein identification was also improved by novel statistical methods utilizing prediction of chromatographic behavior and the non-randomness of enzymatic digestion. To identify proteins by short sequence tags, electron capture dissociation was implemented, improved and finally coupled on-line to liquid chromatography for the first time. The combined techniques can be used to sequence large proteins de novo or to localize and characterize any labile post-translational modification. New computer algorithms for the automated analysis of isotope exchange mass spectra were developed to facilitate the study of protein structural dynamics. The non-covalent interaction between HIV-inhibitory peptides and the oligomerization of amyloid β-peptides were investigated, reporting several new findings with possible relevance for development of anti-HIV drug therapies and understanding of fundamental mechanisms in Alzheimer’s disease.

Style APA, Harvard, Vancouver, ISO itp.

35

Woodling, Kellie Ann. "Using electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry to study modified polypeptides". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012801.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

36

Guan, Shenheng. "Fourier transform ion cyclotron resonance mass spectrometry: Personal computer-based instrument and two-dimensional spectroscopy". Scholarly Commons, 1989. https://scholarlycommons.pacific.edu/uop_etds/3367.

Pełny tekst źródła

Streszczenie:

A personal computer based Fourier transform ion cyclotron resonance mass spectrometer has been designed and constructed. An IBM PC AT compatible computer is used to host the interface of the instrument. The advantages of using a personal computer to host the FT-ICR instrument include: (1) very low cost of the computer; (2) extensive graphic and mathematic capabilities; (3) easy performance alteration or expansion; (4) an abundance of application software; and (5) support for a wide range of output devices. A dedicated digital hardware interface, which provides high speed data transfer and accurate timing control, was assembled on the computer's extension board. The extension board is used to replace the frequency synthesizers and waveform recorders normally used for arbitrary waveform generation and data acquisition at a speed of several mega Hertz. The unique features of the digital hardware design include: (1) common memory for both excitation and data acquisition; (2) control logic for critical timing steps; (3) system memory mapping for fast data transfer. This design has not only led to great reduction in construction cost but has increased the flexibility of the instrument to perform complex experiments as well. A general phase modulation algorithm for the stored waveform inverse Fourier transform (SWIFT) excitation has been developed. The method can be used to generate arbitrary excitation waveforms with optimal dynamic range reduction. The maximum entropy spectral analysis (MEM) has been investigated. When the broad-band MEM method was demonstrated in the host computer, resolution and signal-to-noise ratio improvement was observed. New preamplifier, electron beam circuits, and the sample inlet system of the instrument were designed and constructed with computer control. This provides the instrument with reliability, stability, and functionality. A theoretical model for two dimensional Fourier transform ion cyclotron resonance mass spectrometry has been proposed. The model interprets the physical significance of the modulation of the ion signals in the additional dimension. According to the model, the additional time dimension (which is introduced as the duration between the pair of 2D excitation pulses) determines the speed of the primary ions just before the reaction period. The speed modulation may result in primary ion population modulation. In general, the speed modulation will transfer into ion signal modulation through a variety of channels, such as reactions and ion loss. The model also predicts that the ion modulation in the additional dimension is not sinusoidal (therefore, harmonics exist) and the ion signal modulation has definite phase relationships. The implementation of the 2D technique is developed and demonstrated.

Style APA, Harvard, Vancouver, ISO itp.

37

Xiang, Xinzhen Jane. "Improvements in the analytical capabilities and understanding of Fourier transform ion cyclotron resonance mass spectrometry /". The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu148784969696617.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

38

Blackburn, John William Teasdale. "High-resolution Fourier transform ion cyclotron resonance mass spectrometry and nuclear magnetic resonance spectroscopy of humic substances". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31149.

Pełny tekst źródła

Streszczenie:

Humic substances (HS) are described as a complex mixture of organic molecules formed by incomplete decomposition of plant, animal and microbial matter. They are found in soil, water and air and have many environmental roles, e.g. water retention and metal ion binding in soil. Despite their importance, the molecular composition of HS is poorly understood. This is mostly because of an inability to separate individual molecules from these complex mixtures and then characterise them by standard analytical methods such as NMR and MS. In order improve the understanding of these important mixtures I have studied them using a high-resolution analytical method, Fourier transform ion-cyclotron resonance mass spectrometry (FTICR MS). Initial efforts focussed on testing the, fast, automated data analysis of the large data sets produced. Two pieces of software were compared and the reliability of the formulae assigned by these was critically evaluated. This confident formula assignment was then applied to study the consequences of different ionisation and instrumental parameters on the mass spectra obtained. The use of laser desorption/ionisation (LDI) without the need to employ a matrix required in matrix assisted laser desorption/ionisation (MALDI) was explored. A comparison of LDI and electrospray ionisation (ESI) FTICR MS of natural organic matter samples showed that these methods ionise complementary sets of compounds. The LDI ionised compounds were characterised as aromatics or condensed aromatics and compounds belonging to lower oxygen classes (maximum number at O8), while ESI ionised higher oxygen classes (maximum number at O16) with a vast majority of compounds classified as aliphatic based on their modified aromaticity index. MALDI and LDI spectra produced very similar data with over 90% matching formulas implying that fragmentation is not caused by LDI, as taught previously. My work showed that to maximize the coverage by FTICR MS of the molecular space occupied by these complex mixtures, multiple ionization methods must be used. As a particularly convenient and readily deployable ionization technique, LDI should be included in standard analytical protocols for FTICR MS analysis of NOM. I have explored different parameters and experimental settings to obtain a fuller coverage of the molecular space of NOM, this showed that different experimental conditions enhance peak intensities in different m/z regions of the FTICR MS spectra and that information can be obtained outside of the narrow 200-700 m/z window. To gain chemical and structural information about humic substances beyond what is currently known, experiments aimed to label HS using different isotopes and at specific sites were developed and tested. Two methylation reactions were of particular interest. A methylation that selectively targeted carboxylic acid groups and incorporated deuterium in the form of CD3 groups. An international standard, Suwannee River fulvic acid, was methylated and analysed by high-resolution mass spectrometry in order to gain information on the number and distribution carboxylic acid groups. This proved challenging due to the reactivity of the unknown molecules being difficult to determine in advance. Additionally, the peak separation being reduced to as low as 1.5 mDa pushed the instrument resolution and assignment confidence to their limits. The second methylation method explored used 13CH3I, a nonselective agent reacting with any labile proton, particularly attaching 13CH3 groups to carboxylic, phenolic and alcoholic OH groups. I prepared a methylated sample of fulvic acid from a Red Moss raised bog (Balerno, near Edinburgh) ready for analyses by high field NMR. This investigation yielded structures of a number of phenolic compounds for the first time by NMR.

Style APA, Harvard, Vancouver, ISO itp.

39

Sarowar, Chowdhury Hasan Chemistry Faculty of Science UNSW. "Electrospray ionisation fourier transform ion cyclotron resonance and quadrupole ion trap mass spectrometry of metal-flavonoid complexes". Publisher:University of New South Wales. Chemistry, 2009. http://handle.unsw.edu.au/1959.4/43658.

Pełny tekst źródła

Streszczenie:

Positive-ion electrospray ionisation Fourier transform ion cyclotron resonance and ion trap mass spectrometry have been used to investigate the reactions of the flavonoids 3-hydroxyflavone, 5-hydroxyflavone, 5-methoxyflavoe, quercetin, quercitrin and rutin with monovalent Li+, Na+, K+ and Cs+, divalent Cu2+, Zn2+ and Pb2+ and trivalent La3+ and Eu3+ metal cations. The effect of capillary-skimmer potential difference and the ion residence time in the hexapole ion trap of the Fourier transform ion cyclotron resonance mass spectrometer are systematically investigated for the flavonoid-alkali and divalent metal ion experiment. It is observed that these variables impact significantly on the type of ions observed in the ESI experiments and hence the mass spectra. The binding selectivity of alkali metal ions towards 3-hydroxyflavone, 5-hydroxyflavone and 5-methoxyflavone are determined using the results from FTICR mass spectrometry experiments. The selectivity order follows the order Li+>Na+>K+ for individual flavonoids. Collision-induced dissociation experiments are carried out by Fourier transform ion cyclotron resonance and ion trap mass spectrometry to compare the fragmentation behaviour of metal-flavonoid complexes. Low energy collision-induced dissociation experiments of the [2L+M]+ for 3-hydroxyflavone, 5-hydroxyflavone and 5-methoxyflavone alkali metal complexes show the loss of ligand only. When the energy is increased only the lithiated dimer [2L+Li]+ for 5-methoxyflavone shows the loss of methyl radical along with the ligand. For quercitrin the predominant dissociation pathways are the loss of rhamnose for Li+, Na+ and K+ complexes although aglycone loss is also observed for the K+ complex. The favourable dissociation pathways for rutin are the loss of disaccharide, aglycone and rhamnose for the Na+ complex and the loss of disaccharide for the K+ complex. Collision-induced dissociation data are also used to determine the threshold dissociation energies for displacement of one flavonoid ligand from alkali metal flavonoid complexes. The threshold dissociation energies for loss of one ligand from [2L+M]+ of 5-methoxyflavone and quercitrin follow the order Li+ > Na+ > K+, rutin follows the order Na+ > K+ > Li+ , and 3-hydroxyflavone and 5-hydroxyflavone follow the order Li+ > Na+. For the same metal cation experiment, 5-methoxyflavone system has the highest dissociation energy compared to the 3-hydroxyflavone and 5-hydroxyflavone experiment. Preliminary DFT calculations show that the calculated dissociation energies follow the same trend as the experimental dissociation energies for the simple flavonoid alkali metal cation experiments. For 5-methoxyflavone-divalent metal cation (Zn2+, Cu2+ and Pb2+) complexes loss of methyl radical is the common process. CO loss is also observed for the Zn2+ complex whereas CHO and H2O losses are observed for Cu2+. For 3-hydroxyflavone and 5-hydroxyflavone divalent metal cation experiments loss of ligand is the dominant process. Zn2+ and Cu2+ complexes also show CO loss. La3+ and Er3+ with the same flavonoids show the ligand as the dominant product. For quercetin-divalent metal cation experiment, ligand loss is the dominant process. For quercitrin and rutin various dissociation products are observed where the dissociation occurs via the loss of the rhamnose and/or the disaccharide moieties. Similar dissociation patterns are also observed for La3+ and Er3+ complexes for quercitrin and rutin.

Style APA, Harvard, Vancouver, ISO itp.

40

Yin, Winnie Weixin. "Fourier transform ion cyclotron resonance mass spectrometric study of gas-phase ion-molecule reactions /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847309051562.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

Arkin, C. Richard. "Theoretical treatment of ion motion in an open trapped-ion cell for use in Fourier transform ion cyclotron resonance mass spectrometry". Digital version:, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992745.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

42

Karim, Muhammed. "Study of the post-translational modifications of histone H4 by Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9780.

Pełny tekst źródła

Streszczenie:

Post-translational modification (PTM) of proteins is known to be a method by which protein function can be regulated. The addition of selected chemical groups at specific amino acid residues can act as a switch by which the function of a modified protein can be attenuated. Histones are a group of proteins which are found in the nucleus of eukaryotic cells and interact with DNA, providing it with a structural foundation upon which the chromosome is built. Histone proteins have numerous sequence variants and are known to be extensively post-translationally modified in a dynamic manner. These modifications have a direct effect on the interacting DNA resulting in increasing or decreasing levels of gene transcription. Advancements in analytical instrumentation, when coupled to high resolution separation techniques permit the analysis of increasingly complex biological mixtures. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers unrivalled mass resolving power and mass measurement accuracy, allowing the detailed study of mixtures of intact proteins and their post-translational modifications. These features have been exploited to provide a global view of the PTMs of histone proteins. The work contained within this thesis is a study, by FT-ICR MS, of the modifications of one of the most extensively modified histone proteins; histone H4. Firstly, the modifications of histone H4 were examined after treatment with a potent histone deacetylase inhibitor across several cell lines. The cell lines chosen showed a varying response to treatment with the inhibitor. From the cell lines tested, two which responded differently were further interrogated to elucidate the order in which acetylation occurs in the N-terminal region. Secondly, the modifications of histone H4 were analyzed after exposure to lactic acid over multiple treatment times. Lactic acid is a metabolic by-product, and is of interest when considering the Warburg effect and its role in tumorigenesis. Exposure of cells to levels of lactic acid which can be present under anaerobic conditions (i.e. during intense exercise) showed that lactate is able to inhibit histone de-acetylation. The resulting increase in hyper-acetylated forms of histone H4 could be potentially linked to increased gene expression, a typical observation in tumorigenic cells. Finally, using a mouse model for the neurological condition Rett Syndrome, the posttranslational modifications of histone H4 were investigated. The primary cause of Rett Syndrome is mutation of the DNA binding protein methyl CpG binding protein 2 (MeCP2). MeCP2 has been associated with multiple intracellular functions, one of which is chromatin remodelling. The work carried out showed a link between MeCP2 mutation and tri-methylation of histone H4. In addition, the tri-methylation was not solely identified through the presence of tri-methylated fragments in fragmentation mass spectra. Interestingly, the neutral loss of a methylene group was observed extensively during fragmentation of tri-methylated species. This unreported phenomenon made interpretation of spectra difficult; however, ultimately served as a useful marker for this modification.

Style APA, Harvard, Vancouver, ISO itp.

43

Wallace, James Ian. "The analysis of biological molecules by electrospray ionisation Fourier transform ion cyclotron resonance (ESIFTICR) mass spectrometry". Thesis, University of Warwick, 1999. http://wrap.warwick.ac.uk/73491/.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

44

Alber, George Miles. "Theory and instrumentation for precise mass measurement by Fourier transform Ion Cyclotron Resonance Mass Spectrometry (FT/ICR/MS) /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487777170408073.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

45

Uechi, Guy Takeo. "Infrared photophysics of gas phase ions in a Fourier transform ion cyclotron resonance mass spectrometer". Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1056650065.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

46

Scotcher, Jenna. "Study of the molecular details of p53 redox-regulation using Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/8088.

Pełny tekst źródła

Streszczenie:

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and superoxide (O2 • −) have been shown to serve as messengers in biological signal transduction, and many prokaryotic and eukaryotic proteins are now known to have their function controlled via ROS-mediated oxidation reactions occurring on critical cysteine residues. The tumour-suppressor protein p53 is involved in the regulation of a diverse range of cellular processes including apoptosis, differentiation, senescence, DNArepair, cell-cycle arrest, autophagy, glycolysis and oxidative stress. However, little is understood about the specific molecular mechanisms that allow p53 to discriminate between these various different functions. p53 is a multiple cysteine-containing protein and there is mounting evidence to suggest that redox-modification of p53 Cys residues participate in control of its biological activity. Furthermore, p53 activity has been linked to intracellular ROS levels. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) offers superior mass resolving power and mass measurement accuracy, which is beneficial for the study of intact proteins and the characterisation of their posttranslational modifications (PTMs). The primary goal of the work described in this thesis was to employ FT-ICR mass spectrometry to investigate the molecular details of p53 redox-regulation. The relative reactivity of each of the ten cysteine residues in the DNA-binding core domain of recombinant human p53 was characterised by treatment with the Cys-alkylating reagent N-ethylmaleimide (NEM) under various conditions. A combination of top-down and middle-down FT-ICR MS was used to unambiguously identify Cys182 and Cys277 as sites of preferential alkylation. These results were confirmed by site-directed mutagenesis. Interestingly, Cys182 and Cys277 have previously been implicated in p53 redox-regulation. Alkylation beyond these two residues was found to trigger rapid alkylation of the remaining Cys residues, presumably accompanied by protein unfolding. These observations have implications for the re-activation of mutant p53 with Cys-targeting compounds which result in the death of cancer-cells. Furthermore, the molecular interaction between p53 and the ROS hydrogen peroxide was investigated. p53 was found to form two disulfide bonds upon treatment with H2O2. An enrichment strategy was developed to purify oxidised p53 and top-down FT-ICR mass spectrometry revealed unambiguously that Cys176, 182, 238 and 242 were the oxidised residues. Interestingly, Cys176, 238 and 242 are Zn2+- binding residues suggesting that p53 contains a zinc-redox switch. The mechanism of H2O2 oxidation was investigated, and revealed that oxidation via an alternative pathway results in indiscriminate over-oxidation of p53. Moreover, Cys176, 238 or 242 was shown to act as a nucleophile, and the intracellular antioxidant glutathione (GSH) did not prevent oxidation of the Zn2+-binding Cys residues, providing further evidence for a role in p53 redox-regulation. This study has revealed hitherto unknown details regarding the chemistry of cysteine residues within the important tumour-suppressor protein p53. Furthermore, the analytical power of FT-ICR MS for the study of multiple Cys-containing proteins has been very clearly demonstrated.

Style APA, Harvard, Vancouver, ISO itp.

47

Silwal, Indira K. C. "Characterization of Unknown Chemicals Using Gas Chromatography/Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and AB-Initio Calculations". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SilwalIKC2008.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

48

Zhang, Haizhen. "Characterization of Cucurbituril Complex Ions in the Gas Phase Using Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1582.pdf.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

49

Proschogo, Nicholas William Chemistry Faculty of Science UNSW. "Identification of mammalian lipid material by high performance liquid chromatography and fourier transform ion cyclotron resonance mass spectrometry". Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/42914.

Pełny tekst źródła

Streszczenie:

The analysis of the exact compositions of human lipids is of great importance and can lead to a better understanding of the role of lipids in heart diseases and diabetes. Reverse phase and normal phase high performance liquid chromatography has been used for the analysis of lipid material and applied to beef dripping. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry has been used to investigate the free fatty acids, monoacylglycerides, diacylglycerides and triacylglycerides present in lard and beef dripping with the general conclusion that this is a semi quantitative method. Collision induced dissociation of di- and triacylglycerides was performed using Fourier transform ion cyclotron resonance mass spectrometry with the energy of activation for the fragmentation process investigated and compared using density functional theory and Rice Ramsperger Kassel Marcus statistical theory of fragmentation. The application of tandem mass spectrometry to mice and human cell cultures and plaques from the abdominal aorta of rabbits was conducted using normal phase high performance liquid chromatography with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and quadrupole time of flight mass spectrometry.

Style APA, Harvard, Vancouver, ISO itp.

50

Burkitt, William Ian. "Metal-binding non-covalent protein complexes studied by electrospray ionisation and Fourier transform ion cyclotron resonance mass spectrometry". Thesis, University of Warwick, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429814.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

Rozprawy doktorskie na temat „Fourier transform ion cyclotron resonance mass spectrometry”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych