This project is in the general area of analytical and surface chemistry and in the subfield of separation science. The thrust of this experimental program is to measure the dynamics of sorption-desorption at liquid-solid interfaces in order to assess the role of such dynamics in the behavior and performance of liquid chromatographic separation media and related chemical systems. Measurement of these dynamic processes by relaxation kinetic techniques will provide information concerning the mechanisms of sorption and separation, the viscosity of the interfacial domain, and a quantitative measure of the degree of heterogeneity of surfaces with respect to the energetics of sorption. Chemically modified silicas and related model systems will be synthesized for use in these studies. These materials will be fully characterized by Fourier transform infrared spectrometry, solid state nuclear magnetic resonance spectrometry, and elemental analysis. The role of the solvent in determining the interfacial polarity and viscosity will be determined using fluorescence probe techniques. Results of these studies will be correlated with the performance of these chemically modified silicas as liquid chromatographic stationary phases. This research is expected to yield an improved understanding of the chemistry of separation processes and the general nature of solid-liquid interfacial sorptive systems. This work should lead to the development of improved chromatographic systems for both analytical and preparative scale applications that have broad impact in science and technology.
