ASPECTS OF QUANTITATIVE-DETERMINATIONS WITH POLARIMETRIC DETECTORS INLIQUID-CHROMATOGRAPHY

The overall performance of polarimetric detectors for liquid chromatog raphy has substantially improved in the last few years. Results show r elative standard deviations of 0.50% and as good as 0.25% can be obtai ned using present models. Under reversed-phase conditions using achira l columns, pseudo-rotation due to refractive index related effects pre clude these detectors from performing equally well when operated under static conditions. This situation becomes critical when analyzing com pounds having small specific rotations or mixtures with small enantiom eric excess. Due to such pseudo-rotations, the calibration factors of the polarimetric detectors for two R and S enantiomers are not necessa rily identical. Although the response functions are linear, the negati ve and positive parts do not coincide at zero enantiomeric excess.