PREPARATION AND CAPILLARY COLUMN GAS-CHROMATOGRAPHIC CHARACTERIZATION OF AZA-CROWN ETHER POLYSILOXANE STATIONARY PHASES

Two new kinds of aza-crown ethers, omega-undecylene aza-18-crown-6 polysiloxane (PUAC-18-C-6) and omega-undecylene aza-15-crown-5 polysiloxane (PUAC-15-C-5), were synthesized for use as stationary phases in capillary column gas chromatography. These two stationary phases demonstrate high column efficiency, a wide operating temperature range, good thermal stability, medium polarity and excellent selectivity for n-alcohols, esters and aromatic compounds, similarly to omega-undecyloxymethyl-18-crown-6 polysiloxane phase (PSO-11-18-C-6), and they have unique characteristics which are responsible for the success of separating aniline and other basic compounds without derivatization. The factors which affect the separation mechanism, including dipole-dipole interactions, hydrogen-bonding forces and fitting of solute molecules in the crown ether cavity, are discussed.