The cells employed (10 ml capacity) were placed into an oven; each cell was filled with around 1 g of solid sample. After loading the sample into the extraction cell, the cell was filled with the corresponding solvent up to a pressure of 10 MPa (which ensures the liquid state of the three solvents employed at the three studied temperatures) and was heated-up to the desired temperature. In order to prevent over-pressurization of the cell, a static valve pulses open and close automatically when the cell pressure exceeds the set point. The solvent that escapes during this venting is collected in the collection vial. Then, a static extraction continues, in which all system valves are closed. After extraction the cell was washed with the solvent and subsequently the solvent was purged from cell using N2 gas until complete depressurization was accomplished