Ultrafast supercritical phase chromatography (Fast SFC): a complementary tool for the analyst

In biological or forensic toxicology, due to the very large number of xenobiotics tobe researched or assayed, having effective separation methods is an absolute necessity. Chromatographic methods, whether gaseous or liquid, are ubiquitous and coupled with increasinglyefficient detectors. However, in the vast majority of cases, despite very specific and selectivedetectors (tandem or high-resolution mass spectrometry), chromatographic separation remainsimportant. Separative approaches in the gaseous or liquid phase address the large majority ofneeds. Nevertheless, the chromatographic separation of some molecules remains difficult. Theresolution of these separation problems sometimes requires long and rarely satisfactory developments. Still little used in our laboratories, supercritical phase chromatography (SFC), whichuses carbon dioxide as the main constituent of the mobile phase, opens up new separation possibilities. Unlike gas chromatography, it rarely requires a derivatization step and even allowsthe direct injection of the organic extraction phase. SFC has benefited in recent years fromthe same technical progress as those brought to liquid chromatography (pumps, injector) andfrom the use of a small particle size column (< 2 mu m). This article aims to provide a theoreticalintroduction to this new analytical approach, complementary to the other separative methods, and to describe some examples of applications (x-MMC, quinine/quinidine, stereoisomers ofmethadone and its metabolite EDDP). (c) 2023 Published