Recent advances in chiral detection for high performance liquid chromatography
by Bobbitt, D. R.; Linder, S. W.
The unique response characteristics of optical activity detectors make them an important adjunct to high performance liquid chromatography (HPLC) for the analysis of biologically active molecules. The recent commercial introduction of turnkey, circular dichroism (CD) and polarimetric detection systems compatible with the sensitivity and volume requirements of HPLC will allow these detection approaches to be applied to measurement problems in a number of areas including biomedical research and diagnosis, biotechnology, as well as pharmaceutical science. The CD and polarimetric detectors respond directly to the intrinsic optical activity of the analyte, and both the magnitude and sign of the response can be used for quantitative and qualitative determinations. The information available from these detectors is difficult or impossible to obtain by other methods. In this article, the instrumental basis for both the CD and laser-based polarimetric detectors will be reviewed. Several applications will be described in which the unique response characteristics of these detection systems, either alone or in tandem with other detectors, can be used to identify chiral materials, and determine enantiomeric excess. It will be shown that this methodology is effective either without enantiomeric separation, or under conditions of low enantio-selective resolution. With this technology, a real-time assessment of enantiomeric excess can be obtained as a means to optimize and guide enantio-selective separation processes.