Regulated method for separating a mixture

A method of separating a mixture in a system comprising a plurality of chromatography columns, the method successively comprising, in a cyclic manner, in a given part of the system:

• a step of collecting a raffinate, a step of injecting the mixture to be separated, a step of collecting an extract, and a step of injecting a mobile phase;
• wherein the method further comprises measuring the purity and/or yield of at least one collected fraction chosen from the extract and the raffinate, said measuring the purity and/or yield comprising the following steps:
• the determination, in a node of the system, of the histories of at least two variables that are representative of the concentration of at least two species contained in the mixture to be separated, using at least one fast online detector;
• the determination of the concentration of at least two species of the mixture to be separated in the collected fraction, based on these histories;
• the determination of the purity and/or yield of the collected fraction based on these concentrations.