CHEMICAL INTERACTIONS AT THE SOLID-LIQUID INTERFACE: INVESTIGATIONS EMPLOYING DIAGNOSTIC SEPARATIONS (HPLC, METAL OXIDE, FIELD FLOW FRACTIONATION).

Persistent Link:
http://hdl.handle.net/10150/188099
Title:
CHEMICAL INTERACTIONS AT THE SOLID-LIQUID INTERFACE: INVESTIGATIONS EMPLOYING DIAGNOSTIC SEPARATIONS (HPLC, METAL OXIDE, FIELD FLOW FRACTIONATION).
Author:
SCHUNK, TIMOTHY CHARLES.
Issue Date:
1985
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Significant advances in the understanding of chemical interactions at the solid-liquid interface have been made in this research through the use of diagnostic separations as a surface analysis technique. Diagnostic liquid chromatography has been employed in a detailed investigation of the thermodynamic and kinetic quantities which describe the interactions associated with a temperature induced conformational change in the octadecyldimethylsilane moieties of two different bonded silica materials. As a result of this study the nature of the structure and interactions of the ∼20Å thick interfacial region which acts as the stationary phase in reversed-phase liquid chromatography (RPLC) has been elucidated. The location and orientation of the average intermolecular interactions in the solvated layer stationary phase for solutes of differing hydrogen bonding ability and geometry has been determined as affected by bonded surface coverage, solvent hydrogen bonding competition and the structure of the solvated layer. These refinements in the model of the stationary phase solvated layer provide a much more detailed and accurate description of the intermolecular interactions responsible for retention and selectivity in RPLC than was previously available. A new modification of the method of measuring column mobile phase volume in RPLC employing retention linearization of an homologous series of compounds has been described from fundamental themodynamic principles and a statistically valid data reduction approach. The added advantage of providing thermodynamic information about the chromatographic system under study is inherent in this new technique. The experimental and theoretical bases for the new separation technique of magnetic field-flow fractionation (magnetic FFF) have been demonstrated. It has been shown that FFF techniques can be used in a diagnostic mode to study the dynamic stability of particle suspensions. The application of an external magnetic field to non-aqueous suspensions of sub-micron sized γFe₂O₃ particles, whose surface character has been modified by the adsorption of water, has been shown to enhance the suspension stability with respect to sedimentation. With the choice of proper operational conditions, magnetic FFF has also been demonstrated to be useful in monitoring particle flocculation as a result of its ability to separate particle flocculates on the basis of size.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Surface chemistry.; Absorption.; Liquid chromatography.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Burke, Michael F.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCHEMICAL INTERACTIONS AT THE SOLID-LIQUID INTERFACE: INVESTIGATIONS EMPLOYING DIAGNOSTIC SEPARATIONS (HPLC, METAL OXIDE, FIELD FLOW FRACTIONATION).en_US
dc.creatorSCHUNK, TIMOTHY CHARLES.en_US
dc.contributor.authorSCHUNK, TIMOTHY CHARLES.en_US
dc.date.issued1985en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractSignificant advances in the understanding of chemical interactions at the solid-liquid interface have been made in this research through the use of diagnostic separations as a surface analysis technique. Diagnostic liquid chromatography has been employed in a detailed investigation of the thermodynamic and kinetic quantities which describe the interactions associated with a temperature induced conformational change in the octadecyldimethylsilane moieties of two different bonded silica materials. As a result of this study the nature of the structure and interactions of the ∼20Å thick interfacial region which acts as the stationary phase in reversed-phase liquid chromatography (RPLC) has been elucidated. The location and orientation of the average intermolecular interactions in the solvated layer stationary phase for solutes of differing hydrogen bonding ability and geometry has been determined as affected by bonded surface coverage, solvent hydrogen bonding competition and the structure of the solvated layer. These refinements in the model of the stationary phase solvated layer provide a much more detailed and accurate description of the intermolecular interactions responsible for retention and selectivity in RPLC than was previously available. A new modification of the method of measuring column mobile phase volume in RPLC employing retention linearization of an homologous series of compounds has been described from fundamental themodynamic principles and a statistically valid data reduction approach. The added advantage of providing thermodynamic information about the chromatographic system under study is inherent in this new technique. The experimental and theoretical bases for the new separation technique of magnetic field-flow fractionation (magnetic FFF) have been demonstrated. It has been shown that FFF techniques can be used in a diagnostic mode to study the dynamic stability of particle suspensions. The application of an external magnetic field to non-aqueous suspensions of sub-micron sized γFe₂O₃ particles, whose surface character has been modified by the adsorption of water, has been shown to enhance the suspension stability with respect to sedimentation. With the choice of proper operational conditions, magnetic FFF has also been demonstrated to be useful in monitoring particle flocculation as a result of its ability to separate particle flocculates on the basis of size.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectSurface chemistry.en_US
dc.subjectAbsorption.en_US
dc.subjectLiquid chromatography.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBurke, Michael F.en_US
dc.identifier.proquest8603157en_US
dc.identifier.oclc696815081en_US
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