Advances in the limits of separation power in supercritical fluid chromatography

The use of CO₂-based mobile phases for separations, more generally referred to as supercritical fluid chromatography (SFC), allows to perform highly efficient and fast separations due to its low viscosity and high diffusivity of the solutes in the mobile phase. Nevertheless, the instrumental capabilities of current state-of-the art instrumentation in SFC is still not on the same level as that of ultra-high performance liquid chromatography. Not only is the maximum operating pressure lower, also the extra-column fluidic path is not fully optimized to exploit the possibilities of high efficiency columns packed with small particles. The effect of the strong solvent injection inherent to SFC hinders the optimal implementation of short small particle columns. The current limits in separation power in SFC are discussed and the requirements for future generation instruments are reviewed. An overview is presented of innovations in column technology, separation conditions and optimization of the instrumental design.