High-performance liquid chromatographic separation of peptides on a diol-Gly-Phe-Phe tripeptide-bonded phase

The retention characteristics of some selected peptides (mol. wt. less than 2000 a.m.u.) have been investigated on a diol-Gly-Phe-Phe partitioning phase, bound to 5-microns porous silica. The hydrophobic, positively charged peptides can be separated with mild mobile phases, containing only acetonitrile and phosphate buffer. The peptide selectivity of the diol-Gly-Phe-Phe-bonded phase is uniquely different from that of a C8 column. The dependence of capacity factors on mobile phase pH, ionic strength, and organic solvent concentration demonstrated that the partitioning mechanisms of the diol-Gly-Phe-Phe phase involve multifunctional reversed-phase and cation-exchange processes.