Above the critical temperature and pressure (30.7°C and 73.8 bar respectively for CO₂), the boundaries between gas and liquid disappear. Beyond this critical point, the substance presents the viscosity of a gas and the density of a liquid.

Supercritical Carbon Dioxide (scCO₂) is the most commonly used supercritical fluid.

Our CO₂ treatment is generally carried out at about 40°C. It allows us to handle temperature-sensitive molecules. Furthermore, CO₂ is cheap, non-toxic, non-inflammable, easily available and can also be recycled. Supercritical carbon dioxide acts as a "green" solvent: after depressurisation, there is no residual solvent in the medium.