Derivatization of Secondary Aliphatic Alcohols to Picolinates – A New Option for HPLC Analysis with Chiral Stationary Phase

Abstract

-Derivatization of secondary alcohols (R 1 R 2 CHOH) to benzoates has frequently employed to determine enantiomer ratios using HPLC with chiral stationary phase (CSP). However, a small difference in substituents (R 1 , R 2 ) often results in insufficient separation. To find an alternative derivatization that detects such a small difference, picolinates (2-pyridyl-CO 2 CHR 1 R 2 ) possessing Me/Et, Me/vinyl, Me/acetylenic, Et/n-Pr, and n-Pr/allyl substituents were prepared and separation efficiency was compared with that of benzoates (PhCO 2 CHR 1 R 2 ).Eight commercially available CSPs containing carbamates or benzoates of cellulose and amylose were examined to find that retention factors (k' 1 and k' 2 ) and resolution (R s ) of picolinates were greater than those of the corresponding benzoates and that good to excellent R s values (≥1.25) were recorded over a wide range of CSPs.