Characterization of Octadecylsilane Stationary Phases on Commercially Available Silica-Based Packing Materials by Raman Spectroscopy

Two commercially available solid phase extraction packing materials containing octadecylsilane stationary phases, Isolute C18MF and Isolute C18, were characterized using Raman spectroscopy. Raman spectra of excellent quality can be obtained from such systems and provide direct information about the alkyl chain conformation in the stationary phase. Data from the v(C-C) and v(C-H) spectral regions suggest that the alkyl chains of these stationary phases exist in a highly disordered state which is very similar to that of the neat liquid.