Chiral recognition of cellulose tris(5-fluoro-2-methylphenylcarbamate) toward (R)- and (S)-1,1′-bi-2-naphthol detected by electron ionization mass spectrometry

Abstract

A new method for the detection of chiral recognition was developed through a mass spectrometric study of the desorption of a chiral guest compound (analyte) from a chiral host compound (adsorbent). Optically active cellulose tris(5-fluoro-2-methylphenylcarbamate) (1) was used as the chiral adsorbent, which has been synthesized and used as a chiral stationary phase (CSP) in high-performance liquid chromatography (HPLC). As the chiral analytes, (R)- and (S)-1,1′-bi-2-naphthol (2) were selected. The phenylcarbamate derivative shows high chiral resolving ability in HPLC and completely resolves the enantiomers of 2 with high selectivity; the (R)-enantiomer elutes first, followed by the (S)-enantiomer. A mixture of (RS)-2 and 1 was ionized by electron ionization using a direct insertion probe operated by temperature programming at 32 °C min^–1 from 25 to 400 °C. Reconstructed ion current profiles of (R)- and (S)-2 showed different shapes, which may result from their different adsorption and/or desorption from the chiral adsorbent (1). The chiral discrimination in MS was confirmed using partially deuterated 2 and was quite consistent with the HPLC enantioseparation results using 1 as a CSP.