The roam objectives of this PhD project were to relate anal~ te solubility in supercritical carbon dioxide via molecular structure and also to investigate the factors that influence the solubility and extraction of analytes in a supercritical fluid extraction (SFE) when using carbon dioxide as the solvent. The polarity of an analyte was selected as the key parameter to developing a means of estimating steroid solubility in supercritical carbon dioxide. Polarity can be estimated by the hydrophobicity term, log P (based on partition coefficients), and also of the solubility parameter, 0,. The use of partition coefficient in conjunction with a calculated solubility parameter was demonstrated as a reasonable means of estimating steroid solubility in supercritical carbon dioxide. Experimental determination of the solubility of several steroid compounds with a range in polarities in supercritical carbon dioxide was carried out in order to correlate solute polarity to the solute solubility. A chromatographic method was also investigated based on capacity factor measurements for the prediction of steroid solubility in supercritical carbon dioxide. The application of supercritical fluid extraction (SFE) \\<ith carbon dioxide and modified carbon dioxide for the extraction of four antifungals from an animal feed matrix has been investigated. The SFE experiments were designed to optimize e:\.1:raction conditions for the extraction of the antifungals from the animal feed to allow for the evaluation of the most significant variables influencing extraction. A method was also developed for the analysis of the SFE animal feed extracts by packed-column supercritical fluid chromatography. The modification of the mobile phase with polar modifier was necessary to elute the antifungals. The procedure provided an alternative separation selectivity to the existing reversed phase high performance liquid chromatography techniques with much shorter analysis time.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:245283 |
| Date | January 1996 |
| Creators | Khundker, Sharmin |
| Publisher | Northumbria University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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