Study of stereomeric peptoid chiral stationary phases containing different chiral side chains.

In this study, we investigated six stereomeric peptoid chiral stationary phases (CSPs) successively combining N'-phenyl-proline amide, α-phenylethyl amine, 2-aminocyclohexyl phenylcarbamate and another α-phenylethyl amine under normal phase mode. CSPs 1-4 with R-S-(R,R)-S, R-S-(S,S)-S, R-R-(R,R)-R and R-R-(S,S)-R configuration exhibited much different enantiorecognition abilities. Overall, CSPs 1 and 2 performed better for the 55 analytes tested. CSP 5 with mixed selectors combined partial selectivities of CSPs 1 and 2. CSP 6 as enantiomeric counterpart of CSP 2 exhibited similar enantioseparation ability and reversal elution orders for analytes resolved. For several biaryl type analytes, CSP 6 even outperformed commercial Chiralpak AD-H and Chiralcel OD-H. Excellent resolution of 3,3'-diphenyl-2,2'-bi-1-naphthalol (VANOL) on CSP 6 illustrated its potential application in preparative enantioseparation. Eluting orders of enantiomers on stereomeric CSPs also provided us further insight into enantiorecognition of some analytes.