Liquid chromatographic resolution of beta-amino acids on CSPs based on optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6.
Two chiral stationary phases (CSPs) based on optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 covalently bonded to silica gel were utilized for the first time for the resolution of racemic beta-amino acids using high performance liquid chromatography. All of the 10 beta-amino acids tested were resolved on the CSP containing residual silanol-protecting n-octyl groups, while only five beta-amino acids were resolved on the CSP containing residual silanol groups. The superiority of the CSP containing residual silanol-protecting n-octyl groups and the characteristic retention behaviors of the two enantiomers on the CSP were rationalized to stem from the removal of the residual silanol groups, which can otherwise induce the non-enantioselective retention of the analytes, and the improved lipophilicity of the CSP. The elution orders of the two enantiomers of beta-amino acids were identical on the two CSPs and, consequently, it was concluded that the two CSPs were concluded to utilize identical chiral recognition mechanisms. The different elution orders of the analytes were proposed to be attributed to the presence or absence of pi-pi interactions between the CSP and analytes.
Choi
Hee Jung
HJ
Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Kuemjeong-Ku, Busan 609-735, South Korea.
Ha
Hyun Ju
HJ
Han
Sang Cheol
SC
Hyun
Myung Ho
MH
D000085:Acetates / Q000737:chemistry; D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D043844:Crown Ethers / Q000032:analysis* / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009281:Naphthalenes / Q000032:analysis* / Q000737:chemistry*; D055095:Optics and Photonics; D013237:Stereoisomerism
C530035:(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6; D000085:Acetates; D000596:Amino Acids; D043844:Crown Ethers; D009281:Naphthalenes; C018824:ammonium acetate