Date of Award

Spring 5-15-2018

Degree Type

Dissertation

Degree Name

PhD. Chemistry

Department

Chemistry and Biochemistry

Advisor

Yuri Kazakevich, Ph.D.

Committee Member

Nicholas H. Snow, Ph.D.

Committee Member

Alexander Fadeev, Ph.D.

Keywords

HPLC, Adsorption Isotherm, Hydrophobic Interaction, Thermodynamic

Abstract

This research is to explore a more general column categorization method using the test attributes in alignment with the common mobile phase components. As we know, the primary driving force for solute retention on a reversed-phase surface is hydrophobic interaction, thus hydrophobicity of the column will directly affect the analyte retention. This research describes a method to determine the column hydrophobicity by the ratio of adsorbed acetonitrile and methanol to water on the column surface using excess adsorption isotherm estimation. An excess adsorption isotherm for a binary mobile phase system represents a competitive interaction of both solvent components with the adsorption sites. In the presence of two distinct types of adsorption sites on the surface, an overall isotherm may be represented as a superposition of two isotherms on the different types of surfaces. Assuming complete independence of surface energy on each type of adsorption site, it is possible to mathematically describe this superposition as a sum of two independent isotherms, where coefficient of each individual term represents a relative amount of surface that is responsible for a particular interaction.

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