NEW DEVICE FOR ADDING POLAR MODIFIERS TO CARBON-DIOXIDE MOBILE-PHASE FOR SUPERCRITICAL-FLUID CHROMATOGRAPHY

Adding additional components to supercritical carbon dioxide in superc ritical fluid chromatography can extend or significantly alter the flu id solvating properties. Polar samples which are difficult to be analy zed with pure supercritical CO2 because of their high polarity can be separated by adding polar modifiers to supercritical CO2. In this pape r, a new mixing device using a teflon high capacity filter for adding polar modifiers to carbon dioxide mobile phase is introduced. This new mixing device could keep the amount of modifier in the mobile phase c onstant for a much longer time than a saturator column. The amount of water or methanol dissolved in supercritical CO2 was measured by amper ometric microsensor which is made of thin film of perfluorosulfonate i onomer(PFSI).