A method of extracting a substance comprising the following steps in the following order, wherein any one or more of the steps described are performed by an automated robotic system (200, 300): (i) placing a substrate on which a substance has been adsorbed into a container in the form of an extraction basket; (ii) attaching first and second closures to first and second ends of the container respectively in order to seal the substrate with the substance within the container; (iii) storing the container and maintaining the temperature of the container at a predetermined temperature; (iv) removing the first and second closures to first and second ends of the container and replacing the first and second closures with first and second plungers (508, 510) which first and second plungers (508, 510) are releasably and sealably engageable with the first and second ends of the container respectively; (v) feeding a solvent into the container whilst restricting its exit by means of an electrically-controlled back-pressure regulator to achieve a predetermined pressure of the solvent in the container, wherein the solvent has a critical point and the predetermined pressure is above the critical point of the solvent; (vi) transitioning the solvent into a supercritical fluid within the container by heating to a temperature above its critical point as well pressurising to a pressure above its critical point; (vii) releasing the solvent and an extract comprising extracted substances into a separator (902, 1902); (viii) reducing the temperature and pressure in the separator (902, 1902) to remove a gaseous portion of the solvent from the extract; and (ix) collecting the extract remaining from the separator (902, 1902). (i) placing a substrate on which a substance has been adsorbed into a container in the form of an extraction basket; (ii) attaching first and second closures to first and second ends of the container respectively in order to seal the substrate with the substance within the container; (iii) storing the container and maintaining the temperature of the container at a predetermined temperature; (iv) removing the first and second closures to first and second ends of the container and replacing the first and second closures with first and second plungers (508, 510) which first and second plungers (508, 510) are releasably and sealably engageable with the first and second ends of the container respectively; (v) feeding a solvent into the container whilst restricting its exit by means of an electrically-controlled back-pressure regulator to achieve a predetermined pressure of the solvent in the container, wherein the solvent has a critical point and the predetermined pressure is above the critical point of the solvent; (vi) transitioning the solvent into a supercritical fluid within the container by heating to a temperature above its critical point as well pressurising to a pressure above its critical point; (vii) releasing the solvent and an extract comprising extracted substances into a separator (902, 1902); (viii) reducing the temperature and pressure in the separator (902, 1902) to remove a gaseous portion of the solvent from the extract; and (ix) collecting the extract remaining from the separator (902, 1902).