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Title: Applications of microwave-excited plasmas to the analysis of volatile and gaseous compounds
Author: Whitehead, Paul
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1972
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This thesis is concerned with the application of microwave-excited plasmas as detectors in gas chromatography. An emissive detector system was first investigated. Eluates from a gas-chromatographic column were passed into the plasma of a 2450 MHz electrodeless discharge in argon at atmospheric pressure. The compounds were fragmented, excited and caused to emit characteristic emission spectra which were monitored photoelectrically to provide selective detection of the eluates. A variety of optical and electronic read-out systems were used. Secondly, the emissions from a range of simple organic eluates containing chlorine, iodine, bromine, phosphorus or sulphur hetero-atoms were monitored simultaneously at two characteristic emission wavelengths. It was found that the ratio of the emissions for each compound could be used to determine the quantitative relationship between the number of hetero-atoms and the number of carbon atoms in the compound. A non-selective detector using a novel mode of operation based on the measurement of reflected microwave power was developed. This detector provided sensitive detection of all the gases and organic compounds studied. Its response was independent of the emissive detection system and they could be used simultaneously, to give both selective and non-selective chromatograms. Finally, the emissive detector was used for the determination of metal chelates eluted chromatographically. By monitoring atomic metal emissions this system provided highly sensitive and selective detection of all the metal compounds studied.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available