Rg. Lodevico et al., DETERMINATION OF ENANTIOMERIC EXCESS USING A CHIRAL SELECTIVE SEPARATION MODE AND POLARIMETRIC DETECTION, Talanta, 44(8), 1997, pp. 1353-1363
The quantitative capabilities of a system that combines a chiral selec
tive separation mode with polarimetric detection (CSS/PD) were investi
gated in terms of the ability to quantitate enantiomeric mixtures even
under conditions of poor chromatographic resolution. The laser-based
polarimetric detection system can provide a rotational sensitivity on
the order of 10 mu gdeg corresponding to a minimum measurable quantity
of 10 ng for a compound with a specific rotation of 100 deg (g/ml)(-1
) dm(-1). For the chromatographic studies, peak height and peak area w
ere measured as analytical descriptors of the bimodal response functio
n of this polarimetric detector. Analyses of the dansylated enantiomer
s of the amino acids phenylalanine, threonine, and valine have shown t
hat chromatographic resolution and specific rotation are important fac
tors affecting the shape of the polarimetric response curve. With CSS/
PD, enantiomeric materials can be quantitated at both low and high ena
ntiomeric excess (ee) even at resolutions of 0.3-0.4. (C) 1997 Elsevie
r Science B.V.