Evaluation and application of a positively-charged phenylaminopropyl bonded stationary phase for separation of basic...

Silica-based positively-charged stationary phase bonding phenylaminopropyl (named PHN) was found to produce symmetrical peak shape and higher sample loading for basic compounds. In this work, firstly, surface charge property of the PHN was evaluated by ζ-potential and retention of NO₃^-. A considerable amount of pH-dependent positive charges was confirmed more than that on CSH Phenyl-Hexyl, a commercial positively-charged phenyl stationary phase. Then chromatographic evaluation of standard alkaloids revealed that PHN could offer better peak shape and higher column efficiency at lower pH, and it functioned well under a wide range of buffer ionic strength. The PHN also showed different selectivity for basic compounds compared to the CSH Phenyl-Hexyl. Furthermore, it provided superior peak shape for high sample mass, demonstrating potential applications of this stationary phase in a preparative scale. These results can be explained by the strong charge intensity of the PHN stationary phase. Finally, the PHN was applied to separate a fraction from rhizomes of Corydalis decumbens, and purify dehydrocorybulbine from Corydalis yanhusuo W.T. Wang. Our study indicated the advantages and potential applications of the phenylaminopropyl bonded PHN stationary phase for basic compound separation.