The chromatographic properties of six non-commercially available stationary phases with ester or phosphodiester functional groups embedded into alkyl chain were studied. Zeta potential values of stationary phases suspended in water, organic solvent and their mixtures were measured. Moreover, the selectivity coefficients were calculated on the basis of the retention factor for the test solutes. Separations were performed under hydrophilic interaction liquid chromatographic conditions. Hydrophobic and polar properties of the investigated columns were compared. Based on the chromatographic properties, polar embedded packing materials were classified. Also two phases with different spacer but the same embedded polar group and alkyl chain (Amino-P-C18 and Diol-P-C18) were used for comparison with homemade materials. Amino-P-C18 stationary phase exhibits positive values of zeta potential which is in accordance with the observed anion exchange properties. The highest negative values of zeta potential were observed for Diol-P-C18, together with cation exchange properties. The highest methylene selectivity, polar selectivity and configurational selectivity were observed for the stationary phase with an ester bond and a phenyl group.
Keywords: HILIC; LSER; Liquid chromatography; Polar embedded stationary phase; Radar plots; Statistical methods; Zeta potential.
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