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1
RIGAMONTI, DAVIDE. "Development of neutron and gamma-ray spectrometers for fusion plasma applications." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/198982.
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I neutroni e i raggi gamma emessi da plasmi di fusione termonucleare possono essere rivelati e fornire informazioni sullo stato del plasma e sugli ioni veloci. L’alto flusso neutronico e gamma previsto al JET per plasmi DT, insieme alla necessità di misure con risoluzione temporale di 10-100 ms, richiedono l’utilizzo di spettrometri in grado di operare a tassi di conteggio nel range del MHz. Inoltre, il bisogno di misure ad alta risoluzione energetica pone ulteriori vincoli sulle prestazioni dei rivelatori.
Questa tesi si è incentrata sullo sviluppo, la caratterizzazione e l’implementazione di nuovi rivelatori compatti ad alta risoluzione per la spettroscopia di neutroni e raggi gamma in grado di operare ad alti tassi di conteggio.
All’interno di un progetto europeo finalizzato all’aggiornamento della gamma camera (GC) del JET, è stato sviluppato un prototipo di spettrometro gamma compatto basato su uno scintillatore LaBr3 accoppiato a un Silicon PhotoMultiplier (SiPM). Lo spettrometro offre una buona risoluzione energetica del 5% a 662 keV che migliora a energie più alte permettendo misure accurate nel range 2-6 MeV. Il rivelatore implementa un circuito di formatura del segnale dedicato in grado di accorciare la durata temporale del segnale in uscita dal SiPM. Ciò permette di minimizzare la presenza di eventi di pile-up consentendo il funzionamento a tassi di conteggio superiori a 1 MCounts/s, come dimostrato presso l’acceleratore di Legnaro fino a 3 MCounts/s. I 19 rivelatori sono stati calibrati e installati nella GC del JET nel corso del 2017. L’avanzata risoluzione energetica della GC permetterà di evitare artefatti nella ricostruzione del profilo degli ioni veloci, mentre l’alta capacità di conteggio permetterà per la prima volta di monitorare i cambiamenti del profilo ionico in tempi comparabili al loro tempo caratteristico di rallentamento.
Per quanto riguarda la spettroscopia neutronica, una matrice di 12 diamanti monocristallini è stata installata al JET permettendo misure simultanee di neutroni da 2.5 MeV e 14 MeV. La risposta dei diamanti ai neutroni dipende dalla loro energia. Per neutroni da 2.5 MeV, la risposta è dominata dallo scattering elastico e anelastico mentre per neutroni da 14 MeV si aprono diversi canali di reazione, che permettono misure di spettroscopia ad alta risoluzione. La funzione di risposta della matrice è stata misurata per neutroni monoenergetici presso acceleratori nucleari a diverse energie. La validazione della matrice con neutroni da 2.5 MeV è stata eseguita confrontando i dati misurati dallo spettrometro di riferimento al JET, cioè il TOFOR. I risultati hanno evidenziato il corretto funzionamento della matrice e una moderata risoluzione energetica per plasmi di D. Le eccellenti capacità spettroscopiche dei diamanti per neutroni da 14 MeV, sono state investigate durante la caratterizzazione di un generatore di neutroni DT. I neutroni sono prodotti attraverso reazioni DT che avvengono tra il fascio di ioni misti Dx+ /Tx+ /DT+ (x=1,2) accelerati verso il bersaglio di D e T. I diamanti hanno permesso di risolvere le complesse strutture dello spettro di energia dei neutroni risultanti dalle diverse specie presenti nel fascio. Questo risultato apre nuove prospettive per la diagnostica di plasmi DT su JET e ITER. L’analisi del picco 12C(n,α)9Be del diamante, infatti, permette di identificare accuratamente le componenti sovratermiche in plasmi DT e di studiare fenomeni non classici nel rallentamento degli ioni di fascio.
I risultati presentati rappresentano un avanzamento nello sviluppo di spettrometri di neutroni e raggi gamma per la diagnostica di plasmi da fusione, che combinano la capacità di operare a tassi di conteggio del MHz con la buona risoluzione energetica. I rivelatori sviluppati offrono dimensioni estremamente compatte, ideali per l’integrazione in camere con linee di vista multiple sui futuri reattori a fusione come ITER e DEMO.Neutrons and gamma-rays emitted by thermonuclear fusion plasmas can be detected providing information on fuel and fast ions. The high neutron and gamma-ray fluxes expected at JET in DT plasmas, together with the need to provide time resolution in the range of 10-100 ms, translates into the need of spectrometers capable to operate at counting rates in the MHz range. Moreover, measurements with high energy resolution are necessary to infer detailed information on fast and fuel ions. These pose very challenging requirements on the needed detector performances. This thesis is focused on the development, characterization and implementation of new compact gamma-ray and neutron spectrometers which combine high counting rate capabilities and high energy resolutions. A prototype compact gamma-ray spectrometer has been developed within a European project which is upgrading the JET gamma ray camera (GC) detectors. The prototype detector is based on a LaBr3 scintillator crystal coupled to a Silicon PhotoMultiplier (SiPM). The developed prototype spectrometer features an energy resolution of 5% at 662 keV, which improves for higher energies and provides accurate measurements in the energy range up to a few MeVs. A suitable shaping circuit of the SiPM signal has been implemented to minimize the presence of piled up events allowing operation at counting rates in excess of 1 MCounts/s, as demonstrated with record values 3 MCounts/s at an accelerator. The 19 new detectors have been successfully calibrated and installed during 2017 in the JET GC. The enhanced energy resolution of GC will allow avoiding artifacts in the reconstructed fast ions profile, while the improved time resolution will open the possibility to track for the first time the fast ions profile changes during their slowing down times. In the neutron spectroscopy field, a 12-pixels single crystal diamond matrix has been installed on a vertical line of sight of JET allowing simultaneous measurements of 2.5 MeV and 14 MeV neutrons. The response of diamond neutron spectrometers to 2.5 and 14 MeV neutrons is very different, namely it is dominated by elastic and inelastic scattering for 2.5 MeV neutrons while for 14 MeV neutrons several nuclear reaction channels open up, offering the possibility to perform high resolution spectroscopy. The diamond matrix response function has been measured at nuclear accelerators for incoming different monoenergetic neutron energies. The data validation of the diamond matrix with 2.5 MeV neutrons has been performed by comparing with data taken by the reference 2.5 MeV neutron spectrometer at JET, namely TOFOR. The results indicated that the spectrometer works well and can provide a moderated energy resolution in D plasmas. The excellent spectroscopic capabilities for 14 MeV neutrons, instead, has been explored during the characterization of a 14 MeV DT neutron generator. Neutrons were produced by DT reactions occurring by accelerating a mixed beam of Dx+ /Tx+ /DT+ beam (x=1,2) onto a titanium target containing T/D. Diamond detectors allowed resolving for the first time the complex features of the neutron energy spectra resulting from the simultaneous presence of D+ , T+ , D2+ , T2+ , DT+ species present in the beam. These results open up to new prospects for diagnosing DT plasmas on JET and ITER. The analysis of the diamond 12C(n,α)9Be peak, in fact, will allow accurately identifying supra-thermal components in DT plasma operations and studying non classical phenomena on the beam slowing down. The results presented in this thesis represent a step forward in the development of neutron and gamma-ray spectrometers for fusion plasma diagnostics which combine the MHz counting rate capability with the enhanced energy resolution. The developed instruments feature compact size and are therefore suitable for integration in a multi line of sight camera on the next step burning plasma fusion devices such as ITER and DEMO.
2
Russell, Benjamin C. "Expanding the radioanalysts toolbox : using the latest generation plasma mass spectrometers for nuclear waste characterisation." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/374832/.
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This project investigates the application of sector field inductively coupled mass spectrometry (ICP-SFMS) in low-level radionuclide detection in environmental samples and low-level nuclear waste. The aim was to develop robust and sensitive procedures for measuring medium-long lived emitters of interest to various Nuclear Decommissioning Authority (NDA) sites. ICP-SFMS has been investigated for the measurement of the significant fission product radionuclides of caesium (135Cs and 137Cs) and strontium (90Sr). In the case of some shorter-lived radionuclides such as 90Sr, ICP-SFMS can achieve sensitivities that rival existing radiometric techniques, whilst offering a significant improvement in the speed of analysis. Additionally, long-lived low abundance radionuclides such as 135Cs are not detectable using radiometric techniques, but can be quantified by ICP-SFMS, which is important given their major contribution to the long-term radiological risk associated with deep geological disposal. Measurement of 135Cs also enables measurement of the 135Cs/137Cs ratio, which varies with the source of nuclear contamination, and therefore can provide a powerful forensic tool compared to radiometric 137Cs detection alone. ICP-SFMS has been proven to achieve high sensitivities that will enable low-level radionuclide detection. In order to reach these sensitivities, it is critical to ensure removal of interfering elements that otherwise significantly impact the accuracy of measured values. This led to the development of novel and efficient chemical separation procedures that achieve both a high analyte recovery, and effective decontamination of interferences, which have been proven to be effective for a range of sample matrices including seawater and sediments. The combination of imaginative sample preparation procedures and use of new generation ICP-SFMS offer a streamlining of the process that will contribute to faster more sensitive assessment and clean-up of nuclear sites. This will lead to a reduction in analytical timescales and reduce the demand on existing analytical facilities, benefitting site operators and the NDA.
3
GRIGOLETTO, TANIA. "Dissolucão eletrolítica de ligas de alumínio em cavacos e determinação dos elementos constituintes por espectrometria de emissão atômica com fonte de plasma (ICP-OES)." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11641.
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Tese (Doutoramento)
IPEN/T
Instituto de Quimica, Universidade de Sao Paulo - IQ/USP
4
Hénaff, Gwendal. "Modeling, development, and test of a 3D-printed plasma camera for in-situ measurements in space." Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAX139.
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Les principaux phénomènes régissant la dynamique des plasmas spatiaux, que ce soit l'accélération des particules chargées, la reconnection magnétique ou la dissipation turbulente de l'énergie électromagnétique, sont de nature multi-échelle. Afin de comprendre leur rôle dans le fonctionnement du système Soleil-Terre, que ce soit dans le vent solaire, à la magnétopause ou dans la magnétosphère terrestre, il est indispensable de développer une instrumentation à la fois compacte et performante qui permette le déploiement de constellations de satellites. Cependant, les instruments de référence utilisés pour mesurer la distribution en énergie des particules chargées ont un champ de vue limité. L'ajout de systèmes de déflection électrostatique contourne cette limitation avec l'inconvénient d'alourdir ces instruments, de ralentir leur cadence de mesure et finalement de réduire leur performance. La multiplication des capteurs est alors nécessaire pour recouvrir les performances souhaitées, avec un impact sur le dimensionnement des satellites et finalement sur le nombre de satellites pouvant être déployés. La caractérisation des flux de particules chargées pour l'étude de la météorologie de l'espace souffre des mêmes limitations, celle-ci étant réalisée avec des instruments compacts et au champ de vue limité.La première étape de ce projet de recherche a consisté à développer une méthode de conception d'une nouvelle gamme de spectromètres plasmas qui dépassent ces limitations. Les spectromètres étudiés reposent sur une topologie torique innovante, offrant un champ de vue hémisphérique instantané qui évite l'utilisation de déflecteurs électrostatiques. Leur système de détection planaire font d'eux de véritables caméras plasmas. Les méthodes développées ont permis la génération numérique et la caractérisation par simulation d'un large éventail de caméras plasmas avec différentes résolutions angulaires et qui pourraient répondre à ces besoins scientifiques variés.Un modèle d'instrument répondant aux enjeux de météorologie de l'espace à ensuite été conçu avec une gamme en énergie allant jusqu'à 22 keV. Il possède une capacité duale de détection ions/électrons qui évite l'utilisation de capteurs différents pour la mesure des électrons et pour celle des ions. Destiné à être embarqué sur nanosatellite, il présente une masse de 1,8 kg et un diamètre de 19 cm. Un procédé de fabrication par impression 3D, et de fonctionnalisation du matériau imprimé a été défini et mis en œuvre. Un système de conversion ions/électrons utilisant des feuilles de carbone et permettant l'utilisation duale de cette caméra plasma a également été mis au point. Un instrument intégrant l'optique électrostatique et un système de détection dual simplifié a ensuite été testé sous faisceau d'électrons afin d'obtenir des réponses expérimentales précises en énergie et en angle. Les tests sous faisceau ont montré un comportement très proche de la simulation, renforçant ainsi la confiance dans la modélisation numérique. Le fonctionnement du système de conversion a été testé sous faisceau d'électrons et d'ions. L'une des perspectives à court terme de cette thèse est le développement, avec le soutien du CNES, d'un modèle complet de cette caméra plasma afin de rendre possible la démonstration en vol de cet instrument dédié à la météorologie de l'espaceKey phenomena governing the dynamics of space plasmas - including charged particle acceleration, magnetic reconnection and the turbulent dissipation of electromagnetic energy - are multi-scale in nature. In order to understand their role in the Sun-Earth relationship, whether in the solar wind, at the magnetopause or in the Earth's magnetosphere, it is essential to develop instrumentation that is both compact and high-performance, enabling the deployment of satellite constellations. However, the reference instruments used to measure the energy distribution of charged particles have a limited field of view. Adding electrostatic deflection systems circumvents this limitation, with the disadvantage of making these instruments heavier, slowing down their measurement rate, and therefore reducing their performance. In this case, more sensors are needed to achieve the desired performance, impacting satellite size and, ultimately, the number of satellites that can be deployed. The characterization of charged particle fluxes for studying space weather, conducted using compact instruments with a limited field of view, faces the same limitations.The first step in this research project was to develop a method for designing a new range of plasma spectrometers that overcome these limitations. These spectrometers are based on an innovative toroidal topology, offering an instantaneous hemispherical field of view that eliminates the need for electrostatic deflectors. Their planar detection system makes them true plasma cameras. The methods developed have enabled the numerical generation and characterization by simulating a wide range of plasma cameras with different angular resolutions that could meet these various scientific needs.A model instrument was then designed to meet the challenges of space weather applications, with an energy range of up to 22 keV. It features dual ion/electron detection capability, avoiding the need for separate sensors for electron and ion measurements. Intended for nanosatellites, it has a mass of 1.8 kg and a diameter of 19 cm. A 3D-printing manufacturing process and functionalization of the material have been defined and implemented. An ion/electron conversion system using carbon foils, enabling dual use of this plasma camera, has also been developed. An instrument integrating the electrostatic optics and a simplified dual detection system has been tested under an electron beam to obtain precise experimental responses in terms of energy and angle. The beam tests showed behavior very close to the simulation, reinforcing confidence in the numerical modeling. The principle of the conversion system was tested under electron and ion beams. One of the short-term prospects of this thesis is the development, with the support of CNES, of a complete model of this plasma camera, with the aim to demonstrate in orbit the performances of this instrument dedicated to space weather applications
5
KOMATSU, LUIZ G. H. "Estudo comparativo de nanocompósitos de polipropileno modificado sob condições de envelhecimento ambiental e acelerado." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26380.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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SHIBUYA, ELISA K. "Acoplamento laser - espectrometro de massa de dupla focalizacao com fonte de plasma induzido (LA-HR-ICPMS): estudos fundamentais e analises quantitativa em amostras solidas." reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9279.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:97/09917-0
7
Moser, Matthew A. "Micro-and pulsed-plasmas fine tuning plasma energies for chemical analysis /." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2534.
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Thesis (Ph. D.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains ix, 99 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Pan, Changkang. "Characterization of solvent-plasma interactions for inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30536.
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Bora, Selin. "Boron Determination In Body Fluids By Inductively Coupled Plasma Optical Emission Spectrometry And Inductively Coupled Plasma Mass Spectrometry." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611499/index.pdf.
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Boron element plays an important role for our country since approximately 70% of the world&rsquos reserves are in Turkey. It is widely used in different areas of industry. Besides being vital for the plants, it is important also for human health. It has been shown that high boron exposure does not affect fertility negatively and also with an increasing boron exposure, risk of prostate and cervical cancers decreases. There are different opinions regarding health effects of boron. There are both positive and negative findings. Therefore, determination of boron in body fluids such as urine and blood is necessary to monitor exposed concentration level and its relation with diseases. Furthermore, these studies may contribute to define a reference value for safe maximum daily boron intake. In this study, a method previously developed by our research group was applied for the determination of boron in urine samples. Urine and blood samples were collected from human subjects living or working in different regions of Balikesir where boron reserves are located. While urine analysis was done by using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), due to lower concentrations of boron in blood, Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for blood analysis. A sensitive method was developed using ICP-MS. Samples were digested in microwave oven by applying optimized digestion procedures. Indium (In) and Beryllium (Be) internal standards were spiked into the urine and blood samples, respectively. A sample introduction system containing no glass or silica surfaces was used in ICP-MS to eliminate boron memory effect. Two isotopes of the boron, 10B and 11B, were monitored during the study. Space charge effect due to Na+ ion and carbon interference on B and Be signals was investigated in detail. Limit of Detection was 0.021 mg/L for ICP-OES and it was 2.2 µ
g/L for ICP-MS. The accuracies of the methods were checked by using NIST 1573a Tomato Leaves and BCR Human Hair certified reference materials for urine and blood, respectively.
10
Hartley, James Henry Dean. "Sample introduction and instrumentation in plasma spectrometry." Thesis, University of Plymouth, 1992. http://hdl.handle.net/10026.1/1882.
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Evans, Evan Hywel. "Analysis of organic samples by plasma spectrometry." Thesis, University of Plymouth, 1989. http://hdl.handle.net/10026.1/1747.
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Morse, Ken. "Multi-wavelength analysis of plasma processes." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240236.
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Lofthouse, Simon D. "Sample introduction into inductively coupled plasma mass spectrometry." Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343161.
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Chun, Ka-him, and 秦嘉謙. "Single-particle inductively coupled plasma atomic emission spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209488.
Full textAbstract:
Transient emission of a particle in inductively coupled plasma-atomic emission spectrometry (ICP-AES) depends on the fundamental processes of aerosol desolvation, particle vaporization and atomization, ionization, excitation and diffusion of the analyte. Ideally, the rate of the above processes can be determined from the evolution of the transient emission as the ion plume moves along the central channel of the ICP. However, the dimension of the ion plume is significantly smaller than the central channel. The signal-to-background and signal-to-noise ratios suffer when the entire channel is imaged. Deconvolution of the temporal profile is required to determine the emission intensity of the ion plume versus observation height. Small aperture can be used to locate the vertical emission position accurately, but the evolution of the plume emission is lost.
In this study, a double-slit method has been developed to pin-point two vertical positions of an ion plume. An ion plume travelling along the ICP central channel produces two peaks in the temporal emission profile. The temporal evolution of emission intensity can be correlated to delineate the degree of particle vaporization at the two positions. The relative widths and separation of the two peaks in a double-peak can be used to determine the analyte diffusion rate and particle velocity in the ICP, respectively.
An unicellular green algae, chlorella vulgaris, was used as the test particles. The average Mg content of the algae is equivalent to MgO particles of diameter of 265nm. The strong ionic emission at wavelength of 279.55nm was monitored using a ¼ -m monochromator equipped with a PMT detector. Method of curve fitting was used to filter out the noise with minimum distortion of the peak shape for accurate determination of peak height and peak width. The merits of curve fitting versus methods of smoothing such as moving average and Savitzky-Golay filtering will be discussed.
All transient emissions from the algal cells were detected with sufficient signal-to-noise ratio using a single-slit setup with slit height of 1mm at observation height of 18 mm above the load coil and ICP forward power of 1400 W. However, using the double-slit setup, less than half of the expected double-peaks were observed. One of the peaks in the double-peak can be below the detection limit and the double-peak is lost.
An innovative development of this study is that the relative sensitivity corresponding to the 2 slits can be varied to enhance the intensity of the weaker emission peak. The peak with insufficient signal-to-noise ratio for detection can be enhanced to a level above the limit of detection. The number of observed double-peaks in increased and the observed particles are more representative of the population.
Two types of double-peaks are categorized according to the relative intensity of the first peak to the second peak. A computer model was used to estimate the intensity ratio of the two emission peaks at different observation position of the ICP. The experimental and theoretical ratios agree generally. The theoretical ratio also shows the bias in the population sampled by the double-slit setup.published_or_final_version
Chemistry
Master
Master of Philosophy
15
Andersson, Sundén Erik. "Neutron Spectrometry Techniques for Fusion Plasmas : Instrumentation and Performance." Doctoral thesis, Uppsala universitet, Tillämpad kärnfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121615.
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Neutron are emitted from a deuterium plasma with energies around 2.5 MeV. The neutron spectrum is intimately related to the ion velocity distribution of the plasma. As a consequence, the analysis of neutron energy spectra can give information of the plasma rotation, the ion temperature, heating efficiency and fusion power. The upgraded magnetic proton recoil spectrometer (MPRu), based on the thin-foil technique, is installed at the tokamak JET. The upgrade of the spectrometer was done to allow for measurements of deuterium plasmas. This thesis describes the hardware, the data reduction scheme and the kind of fusion plasma parameters that can be estimated from the data of the MPRu. The MPRu data from 3rd harmonic ion cyclotron resonance and beam heating are studied. Other neutron spectrometer techniques are reviewed as well, in particular in the aspect of suitability for neutron emission spectrometry at ITER. Each spectrometer technique is evaluated using synthetic data which is obtained from standard scenarios of ITER. From this evaluation, we conclude that the thin-foil technique is the best technique to measure, e.g., the ion temperature in terms of time resolution.
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Iwai, H., T. Iguchi, H. Tomita, J. Kawarabayashi, M. Isobe, and C. Konno. "Development of 2.5MeV neutron spectrometer for helical deuterium plasma experiment." IEEE, 2009. http://hdl.handle.net/2237/13885.
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Wellbrock, A. "Cassini plasma spectrometer observations of Titan's ionospheric electrons and ions." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1387441/.
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The work in this thesis uses data from the Cassini spacecraft in the Saturnian system to study the ionosphere and magnetic environment of Saturn’s largest moon Titan. The main instrument utilised is the Cassini Plasma Spectrometer – Electron Spectrometer (CAPS-ELS). Following the presentation of relevant background information, the first part of the thesis is concerned with the analysis of electrons in Titan’s ionosphere and exosphere, whereas in the second part we investigate observations of organic negative ions that can reach masses as high as 13,800 amu/q. The first of two electron topics is the study of photoelectrons in Titan’s ionosphere. We report on observations of photoelectrons (Coates et al., 2007a) in Titan’s exosphere and ionospheric tail that were created in Titan’s lower sunlit ionosphere. We compare observations to hybrid model results (Sillanpää et al., 2011) to confirm that photoelectrons can travel to these locations via magnetic field lines and discuss the implications for Titan’s ionospheric environment and magnetic tail. In the second electron topic we explore regions in Titan’s topside ionosphere where electrons undergo a change in energy of up to 100 eV. These events are observed predominantly on the hemisphere of Titan where the electric field of Saturn’s corotating magnetospheric plasma points away from the moon. A number of events also appear to be associated with pick up ions. The negative ion part of this thesis describes the investigation of factors that control the masses and number densities of negative ions (Coates et al., 2007b, 2009). These have been observed in the altitude range 950 – 1400 km which makes up the main part of Titan’s ionosphere. We find that the highest masses and densities are observed at the lower altitudes within this range. In addition, we reveal solar zenith angle trends for different mass groups, including a region of predominantly low densities near the day-night terminator.
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Ho, Koon-sing, and 何觀陞. "Single-cell analysis using inductively coupled plasma mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hdl.handle.net/10722/196076.
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The technique of single-cell analysis using time-resolved inductively coupled plasma-mass spectrometry has been characterized and optimized. Determination of the metal contents of individual cells provides data on the natural metal contents of the cells and the corresponding distributions in the population. The distribution is a useful indicator of the health and the state of development of the cells. The contents of sorbed metals of individual cells over a duration of time are required to understand the dynamics of metal-cell interactions.
A green alga, Chlorella vulgaris, was used as a model biological cell in this study. The criteria and procedures for proper sampling of the cells into the ICP will be discussed. Ideally, each ICP-MS spike corresponds to one cell, but cell overlapping occurs because the cells enter the ICP randomly. Selection of cell number density and sample uptake rate to minimize spike overlapping will be discussed. A cell counting method based on the frequency of the spikes has been developed.
The distribution of the metal contents of cells was determined by measuring large number of spikes. The minimum number of spikes required was determined by statistical analysis. The spike intensity distribution was correlated with the size distribution of the cells. The peak maximum of the spike intensity distribution was used for the determination of the average metal content of the cells. The use of the peak maximum reduces errors due to spike overlapping in the measurement. Quantitative determination of the metal contents was achieved using standard particles for calibration. Errors in calibration using standard solution nebulization were discussed.
The technique was applied in the study of metal-cell interactions. Sorption of heavy metal ions (as environmental pollutants) by Chlorella vulgaris, and uptake of biometal (as nutrient) and metallodrug (as toxin) by Helicobacter pylori were studied. The technique requires simple sample preparation of removing the culture medium by filtration or centrifugation. The health state of the cells in the presence of toxic metals was related to the change in cell number density. The ratio of the FWHM of the spike intensity distributions of the sorbed metals to the natural metal contents of the cells is identified as a possible indicator of the location of the sorbed metals. The kinetics of metal sorption by the cells can be studied using a single cell culture. The method reduces errors due to uncertainties in cell number density and metal concentration in multiple samples that are required in conventional methods.
The optimal ICP-MS sampling depth of 17 elements, introduced into the ICP by conventional solution nebulization of aqueous standard solutions, has been determined. The elements were selected to represent a wide range of boiling points and ionization potentials. Boiling point of the dried residues and ionization potential of the analyte element were identified as the major factors that determine the optimal sampling position. Since dried sample solution aerosols are effectively nanoparticles, the study provides useful insight on the optimization of the operation conditions and calibration strategies for single-particle analysis using ICP-MS.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
19
Lee, Kin-ho, and 李健豪. "Simulation of single-particle inductively coupled plasma-mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196478.
Full textAbstract:
Time-resolved Inductively Coupled Plasma –Mass Spectrometry (ICP-MS) is a versatile tool for the analysis of single particles such as air particles, nanoparticles, and biological cells. In this study, the processes of particle vaporization and analyte atom diffusion and ionization in the ICP were investigated using computer simulation. Gold nanoparticles of particle diameter 10 to 250 nm were used as the model particle. The parameters of the model were optimized with respect to the experimental data. The relative importance of these parameters was investigated. Simulated ICP-MS intensity versus sampling depth for different particle size was calculated.
Two models of particle vaporization, namely heat-transfer-limited and mass-transfer-limited, were adopted to describe the kinetics of vaporization of the gold nanoparticles. The rate of particle vaporization of the limiting model in each 5-µs time step was used in the simulation. The heat-transfer-limited process dominates at lower position of the ICP. The mass-transfer-limited process takes over at sampling depth of 4mm or above where the ICP temperature is higher than 4000K. The simulation assumed that the gold atoms vaporized from the particle in each time step diffuse independently. The number density of the gold atoms was calculated using the Chapman-Enskog diffusion theory for each subsequent time step. The degree of ionization of the gold atoms was estimated using Saha equation and was assumed to be dependent on the plasma temperature only. The simulated ICP-MS intensity at any instant was the sum of the gold ions in the ion plumes from all previous time steps that pass through a 1-mm sampler cone.
The effects of several simulation parameters on the calculated ICP-MS intensity were investigated. The simulation depth profile of ICP-MS intensity of 100-nm gold nanoparticle was compared to the experimental ICP-MS depth profile. The ICP-MS intensity depends strongly on the ionization temperature of the plasma and the evaporation coefficient of the analyte. The ICP temperature profile, gas velocity, ionization temperature and evaporation coefficient were optimized for the best fit of simulated results to the experimental data.
Simulated calibration curves of gold nanoparticles of nominal diameter of 10 nm to 250 nm are non-linear at any sampling depth. The calibration curve rolls off at high mass due to incomplete vaporization of the larger particles in the ICP. The calibration curve at high sampling depth concaves upward in the low mass range because of significant diffusion loss of the analyte atoms for the small particles.published_or_final_version
Chemistry
Master
Master of Philosophy
20
Lee, Wan-waan, and 李雲鬟. "Studies of single-particle inductively coupled plasma mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208541.
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Carpenter, Robert Christopher. "Inductively coupled plasma-optical emission spectrometry for forensic analysis." Thesis, University of Plymouth, 1985. http://hdl.handle.net/10026.1/2680.
Full textAbstract:
The fundamental characteristics and applications of inductively coupled plasma - optical emission spectrometry (ICP-OES) for forensic science purposes have been evaluated. Optimisation of ICP-OES for single elements using simplex techniques identified an ICP torch fitted with a wide bore injector tube as most suitable for multielement analysis because of a compact analytical region in the plasma. A suitable objective function has been proposed for multielement simplex optimisation of ICP-OES and its effectiveness has been demonstrated. The effects of easily ionisable element (EIE) interferences have been studied and an interference minimisation simplex optimisation shown to be appropriate for the location of an interference free zone. Routine, interference free determinations (<2% for 0.5% Na) have been shown to be critically dependant on the stability of the injector gas flowrate and nebuliser derived pressure pulses. Discrete nebulisation has been investigated for the analysis of small fragments of a variety of metal alloys which could be encountered in casework investigations. External contamination together with alloy inhomogeneity have been shown to present some problems in the interpretation of the data. A compact, corrosion resistant recirculating nebuliser has been constructed and evaluated for the analysis of small fragments of shotgun steels. The stable aerosol production from this nebuliser allowed a set of element lines, free from iron interferences, to be monitored with a scanning monochromator. The analysis, classification and discrimination of casework sized fragments of brasses and sheet glasses have been performed and a method has been proposed for the analysis of white household gloss paints. The determination of metal traces on hands following the handling of a variety of metal alloys has been reported. The significance of the results from these evidential materials has been assessed for forensic science purposes.
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Williams, John G. "Inductively coupled plasma mass spectrometry : analytical methodology and capability." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/844513/.
Full textAbstract:
The performance of the new analytical atomic techniques of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is assessed. A detailed examination of ICP-MS instrumentation was carried out to derive data on performance criteria such as precision, resolution, dynamic range and limits of detection. For most elements, sub ng.mL-1 limits of detection can be achieved together with a linear dynamic range of 4-5 orders of magnitude. Spectral simplicity is one of the attractions of ICP-MS; however, the technique is prone to spectral interference from polyatomic, analyte oxide and doubly charged ions. The significance of these species was studied together with methods for reducing their levels, in particular with use of a cooled spray chamber. Plasma operating parameters were found to effect system performance so a detailed examination of the effects of varying plasma operating parameters was carried out and showed that for ICP-MS systems used in this study, optimisation for maximum elemental signal response resulted in near minimal levels of interference species. Having assessed the optimum operating conditions and potential drawbacks of the technique, the final part of the study was devoted to elemental and isotope ratio determinations using conventional and 'novel' sample introduction methods. The study demonstrates that, apart from the interference problems identified, the technique of ICP-MS is a very useful addition to the field of analytical atomic spectrometry.
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Clarke, Philip Alexander. "Solid sample introduction in Inductively Coupled Plasma Emission Spectrometry." Thesis, Sheffield Hallam University, 1988. http://shura.shu.ac.uk/19472/.
Full textAbstract:
This Thesis describes the progress made in the area of solid sample introduction in Inductively Coupled Plasma Emission Spectrometry (ICP-ES). As an alternative to solution nebulisation two methods of introducing samples to the ICP are investigated. The first of these uses the direct insertion probe technique first described by Horlick and Salin (63). The assembly utilised an electrically operated graphite rod system. This could be used equally well with small volumes of solution sample (5ul) or small masses of solid sample (Ca.5mg). The variables of cup dimensions and material were investigated along with volume and masses of sample used. Results of calibration of both solution residues and solid samples are presented along with details of Limit of Detection and sample Relative Standard Deviation (RSD). The comparative data were found to be in good agreement and it was established that solutions derived calibration data could be used for the analysis of Ni-base samples. Other solid matrices, elemental and alloyed were investigated. These materials divided into two groups, (1) low volatility matrix, from which trace elements were released and only minimal emission from matrix elements was detected and there were no spectral interference effects, (2) volatile matrix in which the matrix vaporized in the same temperature range as the trace elements, giving rise to substantial matrix emission and spectral interferences. It was concluded that DI-ICP-ES is at its most useful when dealing with easily volatilized trace elements in a relatively involatile matrix. The second approach to sample introduction involved the use of an electrothermal vaporization cell. This provided precise control of temperature and offered considerably higher final temperatures than the direct insertion probe system. An Electrothermal Vaporization (ETV) device was designed and built in the laboratory and interfaced to the ICP such that vapour produced in the cell was carried into the plasma discharge by the 'injector' gas stream. ETV was used for liquid and solid samples and results for these samples are presented.
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Fouquet, Thierry. "Mass spectrometry of synthetic polysiloxanes : from linear models to plasma-polymer networks." Electronic Thesis or Diss., Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4756.
Full textAbstract:
Contrairement aux méthodes de polymérisation par voie humide, la « plasma-polymérisation » de précurseurs siliconés (typiquement l'hexaméthyldisiloxane) fournit des couches minces peu solubles, considérées comme riches en chaines courtes et ramifiées, structures cycliques et réticulées, à mi-chemin entre un poly(diméthylsiloxane) (PDMS) et une silice. Ces caractéristiques confèrent des propriétés barrières, électriques ou mécaniques uniques aux substrats traités mais sont autant de difficultés pour leur analyse par spectrométrie de masse. La caractérisation fine d'un plasma polymère serait pourtant d'autant plus utile qu'elle permettrait – indirectement – de proposer ou de valider des mécanismes d'activation et d'oligomérisation du précurseur en phases plasma et solide, connaissance essentielle s'il en est pour la maîtrise des caractéristiques d'un dépôt. Cependant, l'interprétation de données MS/MS en vue de relier un comportement dissociatif à des caractéristiques structurales nécessite l'établissement préalable de règles de fragmentation à partir de modèles pertinents. En l'absence d'étalons plasma-polymère de structure contrôlée, il s'agit donc d'explorer différents modèles potentiels afin d'établir des relations structure/fragmentation pour comprendre les données MS/MS obtenues pour des échantillons réels. Ces études contribueront d'ailleurs à enrichir la littérature sur la fragmentation de polymères siliconés, très réduite en comparaison de polymères à chaine carbonée.A partir des données obtenues depuis les parties solubles de plasma-polymères, les comportements MS/MS d'un ensemble de polymères de référence dument choisis ont été explorés et explicitésThis thesis work aimed at describing the molecular and structural composition of silicon-based plasma-polymers (ppHMDSO) by mass spectrometry. Deposited under a micro-discharge regime at atmospheric pressure, these plasma-polymers exhibit a very low solubility in common solvents, assigned to their highly cross-linked structures, and are hence not easily amenable to ionization. Moreover, structural information cannot be readily deduced from fragmentation data obtained from species extractable from the studied thin films due to the lack of appropriate rules to understand dissociation of the observed gas-phase ions. This research work has thus consisted of developing an analytical strategy to address both of these challenging issues.Owing to the very limited number of articles dealing with tandem mass spectrometry of silicon-containing oligomers, mechanistic investigations were performed on the collision-induced decomposition of selected polymer standards holding different end-groups, expected to be relevant to characterize oligomers suspected to be present in the soluble part of the ppHMDSO samples. Focusing on ammonium adducts, fragmentation routes have first been established for symmetric poly(dimethylsiloxane) (PDMS) polymers holding trimethylsilyl, hydride, or methoxy terminations. POSS molecules were also investigated to understand the influence of cross-linked structures on PDMS adduct dissociation. Some discrepancies between MS/MS spectra of the standards and of the analytes were evidenced, assigned to random branching which could not be modeled by any commercially available compounds
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Catron, Brittany Lyn. "Analysis of Protein:RNA Cross-links by Inductively Coupled Plasma Mass Spectrometry and Tandem Mass Spectrometry." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1337885809.
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Ayeleso, Ayokunle Oluwaseun. "An extreme ultraviolet and plasma spectrometer scientific payload for a cubesat." Thesis, Cape Peninsula University of Technology, 2014. http://hdl.handle.net/20.500.11838/1091.
Full textAbstract:
Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Electrical Engineering
in the Faculty of Engineering
at the Cape Peninsula University of Technology
2014In the Earth’s upper atmosphere, damage to spacecraft electronics is caused by the exposure to extreme ultraviolet (EUV) radiation, solar protons and cosmic rays emanating from the Sun. One particular region where these types of radiation occur is the South Atlantic Magnetic Anomaly (SAMA) region. Therefore, there is a need to design sensors which could be used to investigate the flux and energy levels of radiation in this region. In order to do so, the present study focuses on the numerical simulations of plasma (atomic oxygen ion) in the ionosphere’s F-layer region using the principle of Langmuir single probe theory. Another goal of this study is to investigate the behaviour of a copper plate sensor under exposure to ultraviolet (UV) radiation through simulation and experimentation in a laboratory setting in terms of the photoelectric effect principle. Simulation results of the plasma model of the ionosphere’s F-layer region using an ideal single spherical probe showed that ionospheric plasma parameters such as electron temperature and electron density can be determined using the I−V characteristic curve obtained from the probe. Similarly, the simulation results of the behaviour of the copper plate under exposure to UV radiation showed that UV light with wavelengths shorter than 237 nm produced photocurrents. After calculations and simulations, the stopping potentials that could decelerate electrons emitted with UV radiation wavelengths between 100 nm and 237 nm are, respectively, between -7.6 V and -0.2 V. When comparing the calculated copper stopping potentials with the simulated copper stopping potentials, the results converge for shorter wavelengths. These short wavelengths are relevant in this study because they are comparable to EUV wavelengths (10 nm to 121 nm) in the SAMA region. Therefore, the stopping potential results were used in the experimental design and VUV radiation testing of the sensor prototypes. Two different copper sensor prototypes, namely a spherical extreme ultraviolet and plasma spectrometer (SEPS) sensor and a planar sensor were designed and constructed for the realisation of this project. The planar sensor, with dimensions that fit on the sides of a one unit (1U) CubeSat was developed to minimise the experimental uncertainty observed with the SEPS sensor. The aim of this study is to characterise the sensors and their responses to typical plasma and EUV radiation levels using the facilities available in the Western Cape region (South Africa). Plasma testing was not investigated due to lack of test facilities. Therefore, the investigation into plasma measurements was simulation-based. Experimental EUV radiation testing was conducted. Extreme ultraviolet radiation measurements were performed with different vacuum ultraviolet (VUV) sources, namely a pulsed laser and a deuterium lamp (steady) radiation. These measurements posed challenges due to the significant ambient noise present in the laboratory. Consequently, the study looked at both time and frequency domain analyses as avenues to mitigate the effect of noise on the measurements. The initial VUV pulsed laser radiation experiments, with the SEPS sensor used as a two plate spherical capacitor by connecting its outer grids and positively biased, produced no voltage pulses. Only the significant ambient noise levels were observed. The absence of voltage pulses can be attributed to the fact that electrons escaped the metal sphere too energetically, and may fly through the outer combined grids under the additional acceleration of the positive bias and are not collected. A triple probe structure with a negative inner grid is necessary to slow down electrons enough to be captured by the positive outer grid. Based on this principle of operation, the simpler planar sensor was used for further experimentation. In that way, the experimental uncertainties that are compounded by the concentric spherical construction of the SEPS sensors would be avoided. In the VUV pulsed laser radiation experiment, the time-averaged measured terminal voltages were obtained. The frequency content of the measured terminal voltages was also observed through performing a Fast Fourier Transform (FFT) on the time signals. Significant harmonics were observed at frequencies ranging from 210 MHz to 250 MHz. In addition, these results showed that output voltage pulses were detected through both time and frequency domain analyses. In other experiments with VUV deuterium lamp (steady) radiation, the measured time-averaged terminal voltages obtained from the planar sensor showed significant generation of currents (0 μA, -0.7 μA and 1.0 μA) which compared well with the theoretical calculation (0.69 μA). Conclusively, these results validate the measurement approach and operation of the planar sensor and could be used to design a one unit (1U) CubeSat sensor that measures EUV radiation when launched into space. The study further highlights the challenges that future sensor development will face in terms of the facilities available in the region, due to the very small signals that have to be measured in laboratory environments with high levels of ambient noise.
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Gouy, Pierre-Alban. "Etudes spectrométriques de plasmas de rentrées atmosphériques (Mars-Terre) par torche plasma à couplage inductif à basse pression." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22608/document.
Full textAbstract:
La mise en œuvre de missions spatiales demande à développer de nombreuses technologies clés afin de surmonter certaines étapes cruciales. L’une d’entre elle concerne la rentrée atmosphérique : lorsque le véhicule pénètre dans la couche d’atmosphère, sa vitesse relative très grande par rapport au sol va engendrer des frottements importants ainsi qu’une augmentation de pression. L’énergie cinétique de l’objet va donc être transformée en énergie thermique et chauffer le gaz en formant une onde de choc. Les températures dépendent de la vitesse initiale, de la composition de l’atmosphère et de sa pression. Le gaz ainsi chauffé va s’ioniser et devenir un plasma, il va donc transférer sa chaleur au corps de la sonde non seulement par convection mais aussi par rayonnement. Afin de se protéger, le véhicule dispose d’un bouclier thermique pouvant résister aux phénomènes extrêmes rencontrés lors de la descente. Les contraintes supplémentaires vont imposer une géométrie particulière et un lourd bouclier. Ainsi l’objectif est d’avoir les protections les plus légères et efficaces possibles afin de permettre à la sonde de maximiser son emport en équipement scientifique. Pour cela, un des paramètres clés est de connaître le comportement et le rayonnement du plasma produit lors de la rentrée dans l’atmosphère. Cette thèse se positionne dans ce domaine d’étude: les expériences montées et réalisées ont pour objectif d’observer par moyens spectroscopiques un plasma correspondant à celui rencontré par les sondes spatialesMany key technologies, to overcome some crucial steps, are needed for space missions. One of them concerns the re-entry: when the vehicle enters the atmosphere layer, its high velocity relative to the ground will generate significant friction and an increase in pressure. The kinetic energy of the object will be converted into heat energy and heat the gas forming a shock wave. Temperatures depend on the initial velocity, the atmosphere composition and its pressure. The gas is ionized and become plasma, it will therefore transfer its heat to the body of the probe not only by convection but also by radiation. To protect itself, the vehicle has a heat shield that can withstand extreme phenomena encountered during the descent. Additional constraints will impose a particular geometry and a heavy shield. So the goal is to have the lightest possible and effective protections to allow the probe to maximize its payload. For this, one of the key parameters is to know the behavior of the plasma and radiation produced during re-entry into the atmosphere. This thesis is positioned in this area of study: experiments to create a re-entry plasma are intended to be observed by a spectrometer
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Chen, Guangcheng. "Studies of an end-on inductively coupled plasma atomic emission spectrometer (ICP-AES) and a direct sample insertion inductively coupled plasma atomic emission spectrometer (DSI-ICP-AES)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40036.pdf.
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Fouquet, Thierry. "Mass spectrometry of synthetic polysiloxanes : from linear models to plasma-polymer networks." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4756/document.
Full textAbstract:
Contrairement aux méthodes de polymérisation par voie humide, la « plasma-polymérisation » de précurseurs siliconés (typiquement l'hexaméthyldisiloxane) fournit des couches minces peu solubles, considérées comme riches en chaines courtes et ramifiées, structures cycliques et réticulées, à mi-chemin entre un poly(diméthylsiloxane) (PDMS) et une silice. Ces caractéristiques confèrent des propriétés barrières, électriques ou mécaniques uniques aux substrats traités mais sont autant de difficultés pour leur analyse par spectrométrie de masse. La caractérisation fine d'un plasma polymère serait pourtant d'autant plus utile qu'elle permettrait – indirectement – de proposer ou de valider des mécanismes d'activation et d'oligomérisation du précurseur en phases plasma et solide, connaissance essentielle s'il en est pour la maîtrise des caractéristiques d'un dépôt. Cependant, l'interprétation de données MS/MS en vue de relier un comportement dissociatif à des caractéristiques structurales nécessite l'établissement préalable de règles de fragmentation à partir de modèles pertinents. En l'absence d'étalons plasma-polymère de structure contrôlée, il s'agit donc d'explorer différents modèles potentiels afin d'établir des relations structure/fragmentation pour comprendre les données MS/MS obtenues pour des échantillons réels. Ces études contribueront d'ailleurs à enrichir la littérature sur la fragmentation de polymères siliconés, très réduite en comparaison de polymères à chaine carbonée.A partir des données obtenues depuis les parties solubles de plasma-polymères, les comportements MS/MS d'un ensemble de polymères de référence dument choisis ont été explorés et explicitésThis thesis work aimed at describing the molecular and structural composition of silicon-based plasma-polymers (ppHMDSO) by mass spectrometry. Deposited under a micro-discharge regime at atmospheric pressure, these plasma-polymers exhibit a very low solubility in common solvents, assigned to their highly cross-linked structures, and are hence not easily amenable to ionization. Moreover, structural information cannot be readily deduced from fragmentation data obtained from species extractable from the studied thin films due to the lack of appropriate rules to understand dissociation of the observed gas-phase ions. This research work has thus consisted of developing an analytical strategy to address both of these challenging issues.Owing to the very limited number of articles dealing with tandem mass spectrometry of silicon-containing oligomers, mechanistic investigations were performed on the collision-induced decomposition of selected polymer standards holding different end-groups, expected to be relevant to characterize oligomers suspected to be present in the soluble part of the ppHMDSO samples. Focusing on ammonium adducts, fragmentation routes have first been established for symmetric poly(dimethylsiloxane) (PDMS) polymers holding trimethylsilyl, hydride, or methoxy terminations. POSS molecules were also investigated to understand the influence of cross-linked structures on PDMS adduct dissociation. Some discrepancies between MS/MS spectra of the standards and of the analytes were evidenced, assigned to random branching which could not be modeled by any commercially available compounds
30
Nwogu, Vincent Ikechukwu. "Electrothermal vaporization sample introduction for inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30762.
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Forsgard, Niklas. "Inductively Coupled Plasma Spectrometry for Speciation Analysis : Development and Applications." Doctoral thesis, Uppsala universitet, Analytisk kemi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8169.
Full textAbstract:
In analytical chemistry the main goal is normally to determine the identity and/or concentration of one or more species in a sample. The samples analyzed are often natural samples, containing numerous different species in a complex matrix and the choice of technique for multi-elemental detection is in general inductively coupled plasma spectrometry. The chemical forms of an element can affect many of its characteristics e.g. toxicity, which makes speciation analysis important. Therefore, determination of the identity and quantity of an element is still important, but for many applications measurements of total element concentration provides insufficient information. To be able to perform speciation analysis, separation, identification and/or characterization of the various forms of elements in the sample has to be accomplished. Speciation analysis has been employed in a wide range of disciplines, including for example environmental science, biology and clinical chemistry. This thesis describes work to improve and understand the elemental speciation analysis with liquid chromatography coupled to plasma spectrometry and also highlights the importance and potential of the synergy between atomic spectrometry and molecular mass spectrometry. The combination of the matrix tolerant, robust and very sensitive plasma spectrometry used together with molecular mass spectrometry, which provides structural information and the possibility to identify unknown species, is demonstrated to be a very powerful tool for speciation analysis. In this thesis methods are developed for on-line sample clean-up and pre-concentration coupled to liquid chromatography and plasma spectrometry, which makes handling of small sample volumes easier and also decreases the risk of contamination. The problems associated with organic modifiers in plasma spectrometry are also addressed. Applications of speciation analysis are exemplified by analysis of aluminium-chelated siderophores in field-soil solutions and organic phosphorous species in aquatic sediments. The possibility to analyze un-dissolved samples as slurries with minimal sample preparation is also discussed.
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Sartoros, Christine. "Application of artificial intelligence techniques for inductively coupled plasma spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0016/NQ44574.pdf.
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Sheng, Shijun. "Studies of direct sample insertion inductively coupled plasma mass spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0018/MQ47094.pdf.
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Patel, Pritesh. "Relative quantitation of peptides by inductively coupled plasma mass spectrometry." Thesis, University of Plymouth, 2008. http://hdl.handle.net/10026.1/2077.
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Currently, the detection/quantitation of biomolecules using Inductively Coupled Plasma Mass Spectrometry (ICR-MS) is focused on heteroatom containing (e.g. S. P, Se, Cu) compounds. This limits the scope of ICP-MS as a routine analytical tool in the bioanalytical sciences. To increase this scope novel strategies to incorporate elemental labels have been developed. Chemical derivatisation is one such strategy. Cyclic diethylenetriaminepentaacetic acid anhydride (cDTPA), a bifunctional chelating agent (BFCA), is reacted with N-terminal amines and is subsequently chelated with trivalent metals. This allows the detection of peptides that contained no heteroatom using liquid chromatography (LC)-ICP-MS. The derivatisation efficiency, optimised using LC-UV/vis detection, is approximately 99%. The derivatisation and chelation reactions products are characterised using LC-electrospray ionisation tandem mass spectrometry (ESI-MS-MS). The labelling procedure allowed the relative quantitation of peptides, by differential isotopic labelling. Two individually derivatised peptide samples are chelated with natural isotopic abundance and isotopically enriched 151Eu respectively. The Eu labelled peptides were combined and analysed by LC-ICP-MS. The resulting 153EU:151EU ratio, measured using the pseudo steady state approach for transient signals; is then used to calculate the original peptide proportions using a modified isotope dilution equation. The ICP-MS measured peptide ratio was within 2.8% of the theoretical peptide ratio. The absolute detection limit for the relative quantitation of Eu labelled bradykinin was 5 pmol, which is comparable to current ESI-MS methods. When cDTPA derivatisation was applied to a complex sample multiple by-products were observed in the LC-UV/vis chromatogram. However, the corresponding LC-ICP-MS chromatogram suggested that only singly derivatised peptides were chelated with the metal. To overcome by-product formation monoreactive BFCAs, namely isothiocyanate-benzyl- EDTA (SCN-Bz-EDTA) and isothiocyanate-benzyl-DTPA (SCN-Bz-DTPA). were evaluated as derivatisation reagents. Solid phase analytical derivatisation (SPAD) and solid phase extraction (SPE) were also evaluated for speed and ease of use. The monoreactive nature of SCN-Bz-EDTA and SCN-Bz-DTPA gave singly derivatised peptides when applied to complex samples. However, the resulting derivatisation efficiency was low and no significant improvement in efficiency was noted when SPAD was used. SCN-Bz-EDTA derivatised peptides could not be chelated to trivalent metals, whilst chelation occurred with SCN-Bz-DTPA derivatised peptides. Eu labelled peptides were isolated and selectively extracted by SPE for relative quantitation by LC-ICP-MS. However, due to the instability of the isothiocyanate reagent and instrumental effects the relative error on the measured peptide ratio was greater than 45% when compared to the theoretical ratio. Although the peptide ratio obtained using the SPE method agreed with the ratio from the non extracted sample.
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Burn, Ross Thomas. "Human plasma proteome analysis using chromatography, electrophoresis and mass spectrometry." Thesis, Queen Mary, University of London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500312.
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The human plasma proteome is potentially rich in novel biomarkers for the diagnosis, prognosis of disease and drug development. In the quest for low abundant biomarkers, the problems associated with the complexity of sample and vast dynamic range in concentration have to be overcome. Such strategies include the depletion of the most abundant proteins from plasma, the employment of prefractionation techniques and multidimensional separations. Mass spectrometry can be used to identify and quantify these biomarkers. The most abundant proteins can be depleted from plasma using antibody or dye based affinity columns. Several abundant protein depletion kits were investigated with the aim of selecting the most effective kit for subsequent analyses.
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Handley, Simon. "Measurement of serum lanthanum by inductively coupled plasma-mass spectrometry." Thesis, Queen Mary, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511382.
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Martin, Esther M. "Native mass spectrometry approaches to study zinc-binding plasma proteins." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57641/.
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Human serum albumin (HSA) is a plasma protein that fulfils a wide range of biological functions and is thought to be the major Zn2+ transporter in blood plasma. The high affinity Zn2+ binding site (Site A) has recently been characterised and is located at an interdomain site. In addition to metal binding, HSA is also important in the transport of fatty acids. Previous work has shown that the binding of Zn2+ at Site A and the binding of myristate at fatty acid site 2 are mutually exclusive. It has been predicted that upon fatty acid binding, a conformational change occurs that can disrupt the residues that form Site A. This allosteric interaction could have an impact on the Zn2+ dependent activities of histidine-rich glycoprotein (HRG), a plasma protein involved in blood coagulation. The purpose of this work was to investigate the metal-binding properties of HSA and a peptide derived from HRG using a native MS approach. Furthermore, the possible Zn2+ transfer between the proteins was explored and also whether fatty acids influenced the Zn2+ distribution. Native ESI-MS was able to detect Zn2+ ions associating with HSA although the interactions with fatty acids appeared to be broken upon entering the gas phase. No apparent loss of Zn2+ from HSA was observed by ESI-MS following incubation with myristate which was confirmed by elemental analysis in solution. Travelling wave ion mobility-MS showed no significant conformational changes between apo-HSA and holo-HSA although Zn2+ appears to have a role in stabilising the domain I/II interface. HSA incubated with myristate showed a larger collisional cross section that is in agreement with the X-ray crystal structures. A peptide mimicking the His-rich region of HRG, HRGP330, was found to bind up to 5 Zn2+ ions by ESI-MS and evidence from a combination of circular dichroism spectroscopy, ion mobility and top-down MS/MS indicated that a conformational change occurs upon Zn2+ binding. During CID and ETD, Zn2+-binding fragments were able to be detected in order to map which residues Zn2+ was bound to. However, numerous fragments were detected and so it would appear that several possible binding sites in HRGP330 have a similar binding affinity for Zn2+. Complementary ESIMS and elemental analysis showed that up to 90% of Zn2+ was transferred from HSA to HRGP330 even in the absence of fatty acid. Cu2+ also preferentially bound to HRGP330 over the N-terminal peptide mimic of HSA. Overall this could have implications for how these metal ions are transported in blood plasma as it would appear from this evidence that HRG is a significant competitor for metal ions bound to HSA.
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Booth, Peter. "Laser ablation for sample introduction in inductively coupled plasma spectrometry." Thesis, Sheffield Hallam University, 1991. http://shura.shu.ac.uk/19368/.
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The aim of this research was to investigate laser ablation as a means of sample introduction for the Inductively Coupled Plasma (ICP). This involved the configuration of an ICP spectrometer, a laser and a novel laser ablation chamber. The latter offered the facility of electrothermally heating samples before or during laser ablation. Several operating conditions associated with the ablation process were investigated and optimised. These optimisation studies utilised a variety of metallurgical materials. It was found that the Q-Switched mode of laser operation provided greater sensitivity than long pulsed operation. This research reports the first laser ablation ICP studies on paints and polymers. Ablation of paints was found to provide good precision. This was attributed to a combination of homogeneity and viscosity effect. Operating conditions associated with the ablation process were again examined and found to be independent of sample type. Calibration studies were performed using laser ablation of synthetic aqueous standards. This research includes the first reports of such an approach to calibration. The wide dynamic range associated with conventional ICP was also evident for laser ablation. Calibration followed by analysis of samples providedsemi-quantitative data for paints and polymers. Limits of detection were inferior to solutions nebulisation ICP.
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Dahabiyeh, Lina. "Targeted mass spectrometry for plasma glycoprotein profiling in pre-eclampsia." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/35445/.
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Pre-eclampsia is a common hypertensive disorder of pregnancy that substantially affects maternal and neonatal morbidity and mortality worldwide. Despite decades of research, the aetiology of the disease remains poorly understood, and the clinical management of it is hampered by the lack of reliable diagnostic tests and effective therapy. Several screening tests have been suggested for the prediction of preeclampsia; however, none possess the sufficient specificity and sensitivity. Moreover, multiple pathways are known to be involved in the pathogenesis of pre-eclampsia, so it is very unlikely that a single or a small group of biomarkers will accurately predict the disease. In this thesis, two separate targeted LC-MS/MS methods were developed and validated to quantify plasma glycoproteins in pre- eclampsia to increase the pool of preeclampsia biomarker candidates and explore new pathways associated with the disease. The first method was hypothesis-driven and aimed to quantify the oxidation level of the plasma glycoprotein angiotensinogen (AGT), which has been proposed to be involved in the increased blood pressure characteristic of pre-eclampsia. The second method was hypothesis-generating and aimed to detect glycoprotein fold changes between different disease conditions using a simple and cost-effective conventional LC-MS/MS workflow. For both methods, a reproducible workflow for efficient glycoprotein/AGT extraction from human plasma was developed by coupling ConA lectin affinity chromatography with reversed-phase solid phase extraction fractionation (RP-SPE). Analysis of the enzymatically digested proteins was conducted using targeted LC-MS/MS working under the multiple reaction monitoring mode. For the quantification of the two distinct forms of AGT in the plasma (the sulphydryl-bridged oxidised form and the free thiol reduced form), a differential alkylation strategy was coupled with targeted LC-MS/MS to recognise and quantify the cysteine (Cys) peptides involved in the redox switch of AGT. The developed method enabled the reproducible detection of the two distinct forms of AGT in the plasma with CV% < 15%, and confirmation of the identity of the differentially alkylated Cys peptides was supported by LC-MS/MS. Analysis of clinical plasma samples using the developed method showed a significantly higher level of the oxidised AGT in pre-eclamptic women compared to gestational age-matched normotensive controls (P=0.008), whilst maintaining a similar total AGT level in the plasma. The research findings indicate that the elevated level of oxidised AGT rather than its total level might be a contributing factor to the hypertension characteristic of pre-eclampsia, and provide an extra line of evidence linking the oxidative state and the generation of reactive oxygen species with hypertension in pre-eclampsia. In the second part of the research, 54 clinically relevant glycoproteins were selected to be profiled by label-free targeted LC-MS/MS. Measurement of the analytical precision of the method revealed acceptable CV values for the majority of the assays (median CV 11.8%). Analysis of plasma samples collected from early- and late-onset preeclamptic women using the developed glycoprotein profiling methodology successfully identified significant changes in the level of several proteins in pre-eclampsia. Two of them, apolipoprotein D and kallikrein, are reported for the first time to be altered in the plasma of pre-eclamptic women suggesting that they could be further evaluated as novel biomarkers. Some pre-eclampsia-relevant pathways and biological processes, including iron transport and metabolism, coagulation, and lipid metabolism and oxidative stress were found to be altered in the disease. Moreover, different glycoproteins were changed in early-onset compared to late-onset pre-eclampsia which might reflect different pathophysiological mechanisms. Additionally, the method was applied to identify any altered glycoproteins in plasma samples from women with polycystic ovary syndrome (PCOS). These were subsequently compared with those found to be altered in pre-eclampsia, resulting in the proposal of possible underlying pathophysiological mechanisms that may explain the reported association between the two conditions, such as hypofibrinolysis and thrombophilia and iron overload. Moreover, the study detected, for the first time, significant changes in the plasma levels of vitronectin and insulin growth factor acid labile subunit, suggesting that these may also be further appraised as potential biomarkers for the diagnosis of PCOS. Taken together, the two targeted LC-MS/MS methods developed in this thesis provided relevant information regarding pre-eclampsia by identifying potential pre-eclampsia protein biomarkers. This sheds light on the different biochemical processes altered in the disease and points to possible pathophysiological mechanisms that might assist in explaining the link between PCOS and pre eclampsia, all of which should improve the understanding of the molecular mechanisms of the disease. The present work offers information that may play a key role in improving the health care of women with preeclampsia and serves as a foundational cornerstone for future work.
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Ren, Jian Min. "Direct solid sample analysis by electrothermal vaporization inductively coupled plasma atomic emission spectrometry and mass spectrometry." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41752.
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A series of studies was carried out on the direct analysis of solid samples with inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS). Samples were first vaporized by modified electrothermal vaporization (ETV) systems and the vapor was introduced into the ICP. Inert gas flows were used to increase analyte transport efficiency and to reduce matrix effects.Halogenation reactions were used to improve solid sample vaporization in one of the modified ETV systems. At temperatures ranging from 1000$ sp circ$C to 2400$ sp circ$C pure oxides and carbides were converted to lower boiling point halides and evaporated. Experimental results showed that, with the use of Freon-12 as a gas phase halogenation reagent, nearly 100% vaporization was achieved for $ rm Al sb2O sb3$ (B.P. 2980$ sp circ$C, particle size $<$10 $ mu$m), SiO$ sb2$ (B.P. 2230$ sp circ$C, particle size $<$44 $ mu$m), ZrO$ sb2$ (B.P. 5000$ sp circ$C, particle size $<$74 $ mu$m) and TaC (B.P. 5500$ sp circ$C, typical particle size 5 $ mu$m). The same was true for WC (B.P. 6000$ sp circ$C, particle size $<$10 $ mu$m) if BaCl$ sb2$ was used as a second halogenation reagent. These lead us to believe that we would be able to vaporize samples with almost any inorganic matrix. When the same ETV system was used to analyze four marine sediment reference materials and one coal fly ash reference material, a linear relationship was found between the background corrected peak area and the reference concentration for six of the eight elements monitored.
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Pyen, Grace SungOun. "System for simultaneous determination of hydride-forming elements using inductively coupled plasma optical emission spectrometry." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/27393.
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Hocking, Matthew James. "An advanced wide bandwidth ultrasound absorption and velocity spectrometer for industrial applications." Thesis, Keele University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319023.
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Branagh, Wayne A. "Design and implementation of an autonomous inductively coupled plasma atomic emission spectrometer." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40323.
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The design and implementation of a framework for the automated analysis of samples by inductively coupled plasma atomic emission spectroscopy (ICP-AES) is presented. Various components of this framework have been explored and validated. After initial work was undertaken to determine a suitable pattern recognition technique for sample classification, approaches for detecting the presence of a problematic matrix, and for selecting analysis conditions and calibration methodologies were developed. For the small universe of 14 elements used, the system performed well when matrix effects were due to concomitants in the examined universe. The application of generalized regression neural networks (GRNN) to compensate for spectral interferences and matrix effects and for correcting long-term drift was also examined. In post-processing the analysis results, the size of the GRNN training sets were found to be too small to permit accurate correction of matrix effects though accurate drift correction was possible.
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Wagner, Janet. "Influence of operating parameters on aerosol characteristics of selected inductively coupled plasma optical emission spectrometry nebulizers." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/25973.
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Jarrett, Jeffery Michael. "A comparative study of certain nebulizers for low flow sample introduction for plasma spectrometry." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30076.
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Ruiz, Annia I. "Sample introduction for low pressure microwave induced plasma atomic emission spectrometry." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30324.
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Gellein, Kristin. "High resolution inductively coupled plasma mass spectrometry: Some applications in biomedicine." Doctoral thesis, Norwegian University of Science and Technology, Department of Chemistry, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2233.
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Even though trace elements are present at minute amounts in the human body, they have a considerable impact on human health, either as essential elements in biochemical functions indispensable for life, or on the contrary, interfering with vital processes. Knowledge of the optimal concentrations of trace elements in the human body is therefore of great importance. Since the first systematic determinations of trace elements in human body fluids started in the 1940s there has been an incredible development in analytical instrumentation. The objective of this thesis is to demonstrate successful applications of HR-ICP-MS (high resolution inductively coupled plasma mass spectrometry) in biomedicine.
Research on trace elements in humans is challenging because of very low levels and many different types of matrices. The first important issue regarding trace element analysis is sampling and sample storage. It is essential to control all possible sources of contamination and other factors that can influence the concentrations. Preservation of biological samples is often required, and effects of the frequently used preservation and storage of biological tissue in formalin have been examined in this work. The concentrations of 20 trace elements were determined in formalin where brain samples had been stored at different time intervals ranging from few weeks to several years. The results show that storage of biological tissue in formalin may result in losses of trace elements from the tissue to the formalin, and that the leakage is time-dependent. This emphasizes the importance of controlling all steps from sample collection to analysis.
With its low detection limits, high resolution and multielement capability, HR-ICP-MS offers a considerable potential for further understanding the role of trace elements in biological material. These features were used to develop a method to study protein-bound metals in cerebrospinal fluid (CSF). CSF samples from eight healthy persons were separated by size exclusion HPLC and the resulting fractions were analyzed using HR-ICPMS. The major challenge in this work was the very low concentrations as only 100 μl CSF was injected to the column resulting in 35 fractions of 0.75 ml. It was possible to determine more than 10 elements of clinical interest in the CSF fractions and the method provides an opportunity to study MT and other metal binding proteins in CSF.
Further, the potential to study exposure and intake of trace elements by HRICP- MS was explored by analyzing hair strands of five occupationally unexposed subjects. The trace element profiles of single hair strands were determined by analyzing 1 cm long segments. The challenge in this study was again the extremely small sample size, as the samples had an average weight of 0.05 mg. It was possible however to obtain results for 12 elements in these minute samples and valuable information about intake and exposure for Hg, Se and Sr was obtained.
HR-ICP-MS has the potential to be an excellent tool for obtaining information about disease development and progress. A rare and relatively unexplored neurodegenerative disease (Skogholt’s disease) was studied. The trace element concentrations in whole blood, plasma and CSF were determined in Skogholt patients, multiple sclerosis patients and controls. Increased levels of Cu, Fe, Zn, Se and S in CSF were found in CSF from Skogholt patients. These increased levels were not reflected in blood, and it is quite obvious that the increased levels are not caused by increased environmental exposure. The results suggest that the increased levels of these elements in CSF are due to a leakage of metal binding proteins from blood to the CSF.
Trace elements have been implicated in the development of Parkinson’s disease (PD), and a study was performed on trace elements in serum from Parkinson patients collected in 1995-97, 4-12 years before they were diagnosed with the disease. New samples from more than half of these patients were collected in 2007. No significant differences were found between preclinical levels and controls, except for a lower level of Hg in the patient group. However, when trace element serum levels in patients from before and after they were diagnosed were compared, significant differences for several elements were found. This suggests that trace element imbalances found in PD patients may be a result of disease development rather than a causal factor.
HR-ICP-MS offers a considerable potential for further understanding the role of trace elements in humans. Biological material is often available for analysis only in small amounts. HR-ICP-MS gives the opportunity of simultaneous quantification of many trace elements even in very small samples and with very low detection limits. This promotes new research in the field of trace elements in biological material. HR-ICP-MS also reduces the time and cost per analysis and broadens the amount of information available from a single specimen.
Paper II,III and V are reprinted with kind permission from Elsevier, sciencedirect.com
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Brown, Elizabeth Ann. "Rapid aluminum alloy analysis utilizing inductively coupled plasma atomic emission spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0030/MQ64327.pdf.
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Brown, Elizabeth A. 1973. "Rapid aluminum alloy analysis utilizing inductively coupled plasma atomic emission spectrometry." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30351.
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The goal of this study was the exploration of several techniques for the rapid analysis of aluminum pins by ICP-AES (inductively coupled plasma atomic emission spectrometry).Direct solid sample analysis of the pin by DSI (direct sample insertion) proved to be unfeasible due to incomplete vaporization of the sample from the DSI probe.
A technique called the Real-time Alloy Analysis Technique (RAAT) allowed analyte signals to be monitored during sample digestion (in dilute HCl) and using a ratio method, quantitative results were obtained after a few minutes of initiating sample digestion. This method exhibited fast and simple sample preparation and high precision of <3% relative standard deviation.
An in-solution spark technique (SAD) was used to produce dispersions of the pins in water. The SAD and DSI proved promising as a very rapid sampling technique.
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Bemben, Kevin J. "Laser ablation inductively coupled plasma mass spectrometry for human hair analyses." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97907.
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The goal of this study was to explore the use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for a variety of human hair analyses.Optimization of the inductively coupled plasma mass spectrometry (ICP-MS) operating parameters, radiofrequency (RF) power and carrier gas flowrate, for solid sample introduction showed more than one operating condition can (1) produce a statistically similar maximum elemental signal and (2) have statistically similar optimum signal-to-noise (S/N) ratios. The use of an internal standard was shown to increase the number of operating conditions with statistically similar optimum S/N ratios, and the value of S/N ratios. The high degree of precision exhibited by 34S along hair strands from the same individual (2 - 3 % hair strand to hair strand RSDs) suggests that sulphur may be a suitable internal standard for elements in hair.
The single and multi ablation detection limits (DLs) obtained for elements in powdered hair certified reference materials (CRMs) were similar to what was expected for biological materials using LA-ICP-MS.
The possibility of using LA-ICP-MS to depth profile elements in a hair strand was explored. With the correct operating conditions, LA-ICP-MS may be an effective analytical tool for depth profiling elements in a hair strand.
LA-ICP-MS was used to construct mercury calibration plots using powdered hair CRMs and calibrated hair strands having R2 values of 0.9775 and 0.9522, respectively.
Exogenous deposits lead to confusion in the interpretation of findings from hair. LA-ICP-MS was used to remove an artificial exogenous deposit from a hair strand.