Fourier Transform Infrared Study of A C₁₈ Modified Quartz Surface

Abstract

In reversed-phase liquid chromatography the separation mechanism depends on the solute-stationary phase and solute-solvent interactions. These interactions can be studied under near-normal chromatographic conditions by total internal reflection fluorescence (TIRF) spectroscopy. Quartz crystals chemically modified with n-octadecyl-substituted-silanes, which are common derivatizing reagents used to modify chromatographic surfaces, can be used as a model stationary phase in TIRF studies. To facilitate study of the separation mechanisms using TIRF, surfaces of quartz crystals were chemically modified with silylating reagents and characterized by Fourier Transform Infrared Spectroscopy (FT-IR). Susceptibility tests of the modified surfaces were performed using protic and aprotic solvents. Siloxane bonds were formed, between the reagent and the quartz surface, at high reaction temperature in the absence of any solvent. Siloxane bond formation in the presence of organic solvent at room temperature was observed only when the crystal was previously dehydrated at high temperature.

Key Words:

• FT-IR
• C₁₈
• Quartz