DIRECT RESOLUTION IN SUBCRITICAL AND SUPERCRITICAL-FLUID CHROMATOGRAPHY ON PACKED-COLUMNS CONTAINING TRANS-1,2-DIAMINOCYCLOHEXANE DERIVATIVES AS SELECTORS

Sub- and supercritical fluid chromatography (sub-FC and SFC) are parti cularly suitable techniques for the direct resolution of enantiomers. This article discusses some of the key salient aspects of sub-FC and S FC in the context by packed analytical and microbore columns using chi ral stationary phases containing derivatives of trans-1,2-diaminocyclo hexane as selectors. Some examples of the separation of complex mixtur es of enantiomers using several columns in series are shown, and the i nfluence of analysis temperature, mobile phase composition and the pro perties of stationary phases are also examined. To conclude, the high speed of the technique will be used in the study of fast stereodynamic processes (enantiomerization and diastereoisomerization). The results obtained using modern SFC instrumentation and chiral stationary phase s, are generally more successful when compared to the corresponding hi gh-performance liquid chromatographic method, and make this technique a practical and attractive alternative for the future.