REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF DIASTEREOMERS OF SOME PHOSPHONODIPEPTIDES

The separation of diastereomers of four phosphonodipeptides, derivativ es of 1-aminoethanephosphonic acid (AEP), was studied on different rev ersed-phase sorbents. The influence of the sorbent character and mobil e phase composition on the retention was investigated. It was found ou t that the capacity factors of the S,R and S,S diastereomers were cons iderably different and strongly dependent on the hydrophobicity of the stationary phase. The capacity factors of both diastereomers were inf luenced by pH and the presence of a cation in the mobile phase in a ce rtain pH range. All the above facts are closely connected with the dis sociation constants and conformations of the phosphonodipeptides. An e xplanation of observed behaviour of the compounds studied is proposed.