The versatility of N,O-dialkylphosphoramidate stationary phase-separations in HILIC, highly aqueous RP LC conditions and purely aqueous mobile phase

The chromatographic properties of N,O-dialkylphosphoramidate stationary phase with an octadecyl chain (Amino-P-C18) were studied. Based on the U-shape retention plots over the mobile phase composition for the particular tested compounds (nucleosides and nucleic bases) and solvent excess adsorption isotherms, the separations of the tested compounds were performed in various chromatographic conditions. The separations were performed via hydrophilic interaction liquid chromatography, in highly aqueous mobile phase as well as using pure water as a mobile phase. The obtained results confirm that the specific structure of the amino-P-C18 stationary phase allows solvation over a whole range of mobile phase compositions. The ability of this material to undergo chromatographic separation in extreme mobile phase compositions (hydrophilic interaction chromatography and purely aqueous systems) was also confirmed. Successful separation of test mixtures using pure water as a mobile phase is in accordance with the rules of “green chemistry”.