The design and construction of an acceleration time-of-flight mass spectrometer with improved duty-cycle for use in separation services
The increase of duty-cycle within an orthogonal acceleration time-of-flight mass spectrometer is investigated. An integral part of the study is the design and construction of orthogonal acceleration time-of-flight instrument. Increased duty-cycle is achieved through over-pulsing of the time-of-fligh...
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Swansea University
2002
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| Online Access: | http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638716 |
| Summary: | The increase of duty-cycle within an orthogonal acceleration time-of-flight mass spectrometer is investigated. An integral part of the study is the design and construction of orthogonal acceleration time-of-flight instrument. Increased duty-cycle is achieved through over-pulsing of the time-of-flight source and the removal of unimportant mass ranges by ion gates. The first chapter gives an insight into the evolution of mass spectrometry and more specifically time-of-flight mass spectrometry. Other techniques of duty-cycle increase are discussed and the aims of the investigation detailed. The theory of time-of-flight mass spectrometry forms the heart of chapter two. Theory of ion detectors and the ion injection systems of orthogonal acceleration time-of-flight instruments is also included. Application of the theory was necessary in the design and construction of the instrument. Chapter three details the mechanical and electrical systems used. The instrument can operate in linear and reflectron modes of mass analysis. A removable mass selective quadruple and collision cell are constructed to increase the number of mass analysis techniques available to the time-of-flight analyser. Chapter four describes the characterisation of the instrument. The focusing abilities of the time-of-flight source as well as the instrument's mass resolution and sensitivity are assessed. Spectra produced in reflectron mode operation are compared with library mass spectra. Development of the detection system is contained in chapter five. The ringing obtained with an impedance mismatched output line is eliminated through redesign of the anode Detector gain measurements are also described. Chapter six contains the investigation into duty-cycle increase within the instrument constructed. |
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