Proteins--Separation

The applicability of a recently developed octadecylalumina (ODA) stationary phase for the preparative separations of proteins and peptides is compared with that of conventional Octadecylsilica (ODS) phases. Chromatographic peak widths, peaks areas, and recoveries of polypeptides were obtained from both types of phases. The ODA phase compares favorably with the ODS phase on small peptides, but exhibits low recoveries on high molecular weight proteins. The results are attributed to the unique fused-microplatelet shape of the ODA particles.

Alumina-based stationary phases are evaluated for the separations of proteins and peptides by reversed phase high performance liquid chromatography. Separations are compared to those obtained on a widely-used octadecylsilane (ODS) phase. The separations of peptides on alumina-based stationary phases are found to be superior while separations of proteins are inferior as compared to those found on ODS phase. The superior performance of peptide separations on alumina-based columns is attributed to lower pore size and uniquely-shaped particles of the alumina. The retentions of peptides and proteins on both alumina and silica-based stationary phases are shown to be governed by hydrophobic interaction mechanisms.