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Title: Interfacial adsorption in a gas-liquid chromatographic system
Author: Rees, G. J.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1991
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Chromatographic retention due to adsorption at the liquid/gas and liquid/solid interfaces is possible in gas-liquid chromatographic (GLC) systems, especially with polar solutes from a non-polar stationary phase. The variation of retention volumes with sample size at 60oC on several series of columns, using different support materials, was studied for di iso-propyl ether (DIPE), a polar solute, on squalane, a non-polar stationary phase. Isolation of the total adsorption contributions to retention was then performed using a semi-empirical curve fitting procedure devised by Mathiasson and Jonsson. The adsorption retentions at infinite dilution on a fully wetted porous silica support (Porasil F) was extrapolated to zero loading where the gas/liquid interfacial area (Ax) approaches the value of the support surface area (As). As was measured using the BET nitrogen adsorption method, and the sum of the support/liquid and vapour/liquid adsorption coefficients was obtained. The solid/liquid interfacial adsorption coefficient, Ks, was estimated from adsorption liquid chromatographic parameters, and was found to be small in comparison with the gas/liquid interfacial adsorption coefficient, Kx. The variation with liquid loading of the adsorption contribution to retention on two silanised supports (Chromosorb P-AW DMCS and HMDS treated Porasil F) was studied. The gas liquid interfacial area at high loading was found to be small in comparison with that of untreated Porasil F, and comparable with values obtained by other workers. At squalane loadings where a wetting transition is postulated on the silanised support, the magnitude of Ax approaches that of the unsilanised support, and helps confirm the model for the wetting transition proposed by Conder and coworkers.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available