Geometric isomers, liquid chromatographic

Armstrong, D.W. and DeMond, W., Cyclodextrin bonded phases for the liquid chromatographic separation of optical, geometrical, and structural isomers, J. Chromatogr. Sci., 22, 411, 1984. 

B Stancher, F Zonta. High performance liquid chromatographic determination of carotene and vitamin A and its geometric isomers in foods. Applications to cheese analysis. J Chromat 238.217-225, 1982. 

G Panfili, P Manzi, L Pizzoferrato. High-performance liquid chromatographic method for the simultaneous determination of tocopherols, carotenes, and retinol and its geometric isomers in Italian cheeses. Analyst 119 1161-1165, 1994. 

D.W. Armstrong and W. DeMond, Cyclodextrin Bonded Phases for the Liquid Chromatographic Separation of Optical, Geometrical, and Structural Isomers, J. Chromatog. Sci., 22(1984)411. 

C.A. Chang and Q. Wu, Comparison of Liquid Chromatographic Separations of Geometrical Isomers of Substituted Phenols with P- and y- Cyclodextrin Bonded Phases, Anal. Chim. Acta, 189 (1986)293. 

Fig. 7.3. High-performance liquid chromatography (HPLC) chromatogram taken at 234 nm of CLA geometrical isomers supplied by Matreya. Same chromatographic conditions as in Figure 7.1. Insert differences in the ultraviolet spectra of CLA geometrical isomers.

Three geometric isomers of [Co(D-aspartate)(L-2,4-diaminobutyrate], cis-cis, trans-trans, and fac, have been prepared and can be separated by high-pressure liquid chromatography. The kinetics of the interconversion of two of the isomers with each other, and with the third isomer, in the presence of active charcoal, was investigated, using o.r.d. and chromatographic separation, and a scheme involving a network of three reversible reactions is proposed. ... 

Liquid crystals have found widespread use as stationary phases in gas chromatographic applications due to the benefits of coupling the usual analytical strengths of gas chromatography with the unique structure and shape selective properties of the liquid crystalline phase. Interaction of solutes with the orientational order provided by the anisotropy of the liquid crystal stationary phase allows for the effective and selective separation of positional and geometric isomers. This remarkable solute structural discrimination is especially important for the separation of isomers that have similar physical properties and thus cannot be conveniently separated on conventional capillary columns that mainly differentiate on the basis of boiling point/molecular weight or polarity differences. The mechanism of separation in liquid crystalline stationary phases is based on specific intermolecular inter-... 

---