AUTOMATED ONLINE SOLID-PHASE ADSORPTION SUPERCRITICAL-FLUID EXTRACTION SUPERCRITICAL-FLUID CHROMATOGRAPHY OF ANALYTES FROM POLAR-SOLVENTS

An automated setup for on-line solid phase adsorption (SPA)/supercritical fluid extraction (SFE)/supercritical fluid chromatography (SFC) was evaluated. Low nanogram amounts of analytes dissolved in ethanol were delivered in the form of injections (greater-than-or-equal-to 10 muL) to the solid phase adsorbent consisting of deactivated glass beads, and the analytes were then extracted with supercritical carbon dioxide. The analytes were applied to the adsorbent by an autosampler, which also controlled rinsing and adsorption times. During the chromatographic run, the adsorbent was automatically cleaned with high density supercritical carbon dioxide to be ready for the subsequent injection. Memory effects were between 0 and 4 % depending on the analyte, and the reproducibilities were between 6 and 17 % of the relative peak areas.