The manipulation of interfacial architecture for chemical analysis

This dissertation explores the role and manipulation of the interfacial structure in chemical analysis. Chapter 1 discusses the design and fabrication of thiol-derivatized cyclodextrin monolayers at gold for the studies of molecular recognition properties. The strategy is to transfer the well-known host-guest chemistry of cyclodextrins to gold surfaces. A variety of surface sensitive techniques were employed to characterized the interfacial structures of the monolayers formed from the derivatives. The molecular recognition properties of the monolayers were demonstrated by the QCM experiments;Chapter 2 discusses the effect of interfacial structures of metalloporphyrin at the electrode surface on its catalytic potency. Two different thiol-derivatives of cobalt-porphyrin with different expected orientations as monolayers chemisorbed at gold were synthesized. Correlation between the interfacial structures of the monolayers and the electrocatalytic potency will be discussed in the paper;Chapter 3 describes a new route for the modification of glassy carbon surfaces by electrochemical oxidation of amine-containing compounds. The factors affecting the modification were carefully studied by immobilizing a wide variety of amine-containing compounds. Possible applications for the electrocatalytic and biosensor fabrication will be discussed;Chapters 4 and 5 will discuss another novel variant of EMLC. The approach is based on the control of the adsorption/desorption of surfactant-like additives to the mobile phase by the application of an applied potential to the stationary phase. Chapter 4 will demonstrate the idea through affecting the electrosorption of three alkylaniline compounds using different supporting electrolytes in the mobile phase. Chapter 5 further demonstrates the capability of this technique by modifying a carbonaceous stationary phase to facilitate the separation of optical isomers using the chiral selector. It will be demonstrated that the chiral selectivity of the separation can be manipulated by controlling the amount of [beta]-cyclodextrin immobilized at the stationary phase through the changes in the potential applied to the stationary phase. A mechanism is proposed that qualitatively explains the basis of the observed separations