Thermally immobilized cellulose acetate butyrate on silica particles as stationary phase for high-performance liquid chromatography

Reversed-phase liquid chromatography is the most widely used analytical technique nowadays. However, it generates a large volume of toxic organic residues and presents poor separations of small polar molecules in traditional stationary phases. In this work, cellulose acetate butyrate was synthesized and used as a reversed-phase coating for separating compounds using highly aqueous mobile phases, reducing organic solvent consumption and minimizing the supra-cited problems. Cellulose acetate butyrate presented a degree of substitution of 0.65 (±0.05) by 1H nuclear magnetic resonance, resulting in hydrophilic and hydrophobic groups in the polymer. The stationary phases were characterized physicochemically by infrared spectroscopy, indicating the polymer attachment on the silica surface with 180 m2 g-1 of surface area and 22 nm of mean pore size. The stationary phase was column-packed and chromatographically characterized by separating the Tanaka mixtures. These separations occurred in reversed-phase mode with hydrophobic and hydrophilic interactions related to the acetate/butyrate and hydroxyl groups from cellulose derivative. The stationary phase showed unique selectivity for separating small polar molecules with 90 % water in mobile phases. Cellulose acetate butyrate stationary phase can potentially separate polar compounds requiring high water contents, making reversed-phase liquid chromatography closer to the Principles of Green Chemistry.