Improvement of peptoid chiral stationary phases by modifying the terminal group of selector

The role of a terminal group of a peptoid selector in a chiral separation was investigated. Six chiral stationary phases (CSPs) with the terminal groups replaced by achiral alkyl groups (n-butyl, t-butyl and diisopropyl) and chiral groups ((1R, 2R)-2-aminocyclohexyl phenylcarbamate, N'-phenyl-L-proline amide and N'-phenyl-L-leucine amide) were synthesized. Achiral terminal groups with different steric hindrances did not broaden the enantioselectivity, but improved the separation factors for some analytes, probably due to the improvement of interactions between the analytes and peptoid chain. Introducing new chiral terminal groups proved an effective way to broaden the applicable spectrum of peptoid CSPs.