In Situ Attenuated Total Reflection Infrared Spectroscopic Monitoring of Supercritical CO2 Extraction for Green Process Applications

Supercritical CO2 (scCO2) extraction of valuable chemicals from food, biomass, and residues thereof has recently been recognized as a sustainable process. In this study, we present a new design of an attenuated total reflection infrared (ATR-IR) spectroscopic cell for monitoring the extraction of fatty acid from almonds under scCO2 conditions. The newly designed ATR-IR cell allows in situ monitoring of changes of the composition of the almonds during the scCO2 extraction process at a pressure of up to 450 bar. Extracted components can be spectroscopically followed at a time resolution of 30 s. This allows fast and facile optimization of scCO2 conditions such as temperature, pressure, and extraction time.