OPTIMIZATION OF CHIRAL RESOLUTION USING PACKED-COLUMNS WITH CARBON DIOXIDE-BASED MOBILE PHASES

Optimization of chiral resolution, using carbon dioxide based mobile p hases, must take into consideration the individual contributions of an alyte retention, selectivity, and efficiency. Each of these factors ma y be independently affected by changes in pressure, temperature, or st ate of the mobile phase. The ability to control retention by different means reflects an advantage of carbon dioxide based mobile phases ove r conventional HPLC mobile phases. Utilization of this advantage requi res that the effects of each of these factors on each contributor to r esolution be known. The cumulative effect that each of these variables has on retention, selectivity and efficiency suggests that maximum re solution is obtained using low pressures and temperatures. Maximum res olution (at fixed k') results from low temperatures and high pressures . The latter may be of more practical importance when speed of analyse s and detection limits are considered. (C) 1997 Wiley-Liss, Inc.