Supercritical Fluid Chromatography in Clinical Chemistry

Abstract

AbstractSupercritical fluid chromatography (SFC) employs a gas taken above its critical temperature and critical pressure to where it forms a supercritical fluid (SF). SFs have properties of both gases and liquids. They have lower densities and viscosities and higher diffusion coefficients than liquids, but they also have the solvating power of a liquid and can dissolve nonpolar and many polar compounds. As such, these favorable properties combine to make SFs an excellent mobile phase for column chromatography. The SFC technique is highly versatile in that it can be used with either packed columns (similar to high‐performance liquid chromatography (HPLC) columns with the same variety of stationary phases available) or open‐tubular columns (similar to gas chromatography (GC) columns and employing the same types of coatings) which can be interfaced with a very wide array of detectors. In addition, SFC avoids high temperatures during the chromatographic separation and in most cases the need to derivatize analyzed compounds. These features make SFC particularly well suited to the separation and assay of clinically important biomolecules. As SFC instruments have become commercially available, numerous applications have been explored in the areas of drug monitoring, toxicology, environmental contaminants, and the measurement of physiological biomolecules. Despite its potential, SFC enjoys limited use in clinical chemistry laboratories currently. Greater efforts are needed to improve sensitivity, standardize and validate assays, and work toward high‐volume throughput capabilities.