Extended zones of operations in supercritical fluid chromatography

The pressure and temperature ranges within which supercritical fluid chromatography is operated are generally decided based upon limitations imposed by the instrument or by the stationary phase. Because the maximum pump outlet pressure of most commercial instruments is near 400 bar and the maximum temperature at which most chiral stationary phases are stable is usually below 318 K, the possibility of performing analyses at sub-ambient temperatures (e.g., below 293 K) and under sub-critical pressures (i.e. below 73.8 bar) should be explored. This work investigates the performance of separations made in this unusual zone of operations, which might be attractive for some relevant SFC separations.

► Many separations performed by SFC are done in the supercritical fluid region.
► However, faster separations could be made under subcritical temperatures and pressures.
► There the outlet pressure could be markedly decreased and faster separations performed.
► The performance of separations performed in the subcritical region is examined.