Chiroptical detection during liquid chromatography: Applications to stereoanalysis and stereodynamics

Abstract

Qualitative and quantitative use of polarimetry at one wavelength for detection during liquid chromatography is briefly reviewed. Acquisition of circular dichroism spectra by stopped-flow and nonstop measurements has been further developed. Reasons are given why the angle of rotation, i.e., the polarimeter, is preferred for monochromatic use and differential absorbance, i.e., the dichrograph, for polychromatic requirements. Both methods are demonstrated by novel applications, mainly to enantiomers which interconvert thermally via intramolecular processes.

Chiroptical detection during liquid chromatography: Deconvolution of overlapping peaks of enantiomers and its applications

“…1), the other one should be taken to be equal except for sign, i.e., C + = −C − . On the basis of these ratios and the experimental chromatograms A() and ␣(), our general computer program 7,11 SEPP for Windows 12,13 calculates the deconvolved curves A + (), A − (), a + (), and ␣ − (). The procedure described here for photometry/polarimetry is identical for photometry/ circular dichroism.…”

“…The basic functions of the original DOS version 7,11 of this program were adapted to the Microsoft Windows environment and additional tools, like the ones mentioned below, were implemented.…”

Fluorous “racemic” mixture synthesis: Polysaccharide‐based chiral columns for simultaneous demix and enantioseparation of racemic fluorous tagged compounds

“…The advantages of the FRMS strategy are (Table 1): (1) enantiopure starting materials are not necessary; (2) racemization in a reaction can be disregarded; (3) two enantiomeric products can be simultaneously obtained by single fluorous tag; and (4) the efficiency of the present FRMS can be maximized by the auxiliary use of circular dichroism (CD) and/or optical rotation (OR) HPLC spectroscopy to determine the absolute configuration of products. [65][66][67][68] In conclusion, we have reported the proof of concept experiments of FRMS (fluorous ''racemic'' mixture synthesis). By using a polysaccharide-based chiral column to enantioseparate racemates bearing fluorous tags, we have …”

Reliable assay of extreme enantiomeric purity values by a new circular dichroism based HPLC detection system

“…The published applications of CD detection refer to the use of either noncommercial detectors [18][19][20][21] or CD spectrometers adapted to HPLC/CD measurements. [7][8][9] Some reports concern also the CD monitoring in the near-IR 21 or vibrational region. 17,22 The analytical applicability of scattered circularly polarized Raman optical activity has been also investigated.…”

“…23 The peculiar advantages in the use of CD baseddetection systems have been reviewed by several authors. 5,6,8,9,14,24 However, the most interesting analytical applications are here revisited through the results obtained with a new sensitive and versatile CD based detection system. In particular, for the first time the CD detector has been used for the validation of the e.p.…”