Monitoring the mobile phase composition in supercritical fluid chromatography

Abstract Adding additional components to supercritical CO 2 is supercritical fluid chromatography can extend or significantly alter the fluid solvating properties. Polar samples that the difficult to analyse using pure supercritical CO 2 because of their high polarity can be separated by adding polar modifiers to the supercritical CO 2 . A method for monitoring the mobile phase composition in modified supercritical fluid chromatography is introduced. The amount of water or methanol dissolved in supercritical CO 2 was measured using an amperometric microsensor made of a thin film of perfluorosulphonate ionomer.