Abstract
The effect of hydrophobicity of amino acid subunits on the retention of dipeptides with phosphate buffer as the eluent in RP-HPLC was studied, it has been observed that the capacity factor for dipeptides combined of amino acid subunits with hydrophobicity smaller than that of Ala is smaller than 0.4, and these dipeptides had better be separated by reversed-phase ion-pair liquid chromatography or ion chromatography. Otherwise, the dipeptides combined of amino acid subunits with hydrophobicity larger than that of Ala can be separated by RP-HPLC. It has been observed that there is a good linear relationship between Ink' values in RP-HPLC with the same eluent and different packing materials used or the same packing material and different eluents containing low concentration of different organic modifiers used.