Supercritical-phase mixed chromatography method and installation for implementing same

An installation for the supercritical fluid chromatography of a product, comprising:

• two supercritical fluid pumps, one of analytical capacity, the other of preparative capacity, mounted in parallel, only one of which is operational during operation of the installation,
• a first routing valve upstream of said pumps, which is operated so that a supercritical fluid is allowed to flow toward the operational pump,
• two systems for the injection of at least one sample of the product into at least two chromatography columns respectively, the injection system and the column size being chosen according to whether the path is for analytical or preparative chromatography, with the systems being mounted in parallel downstream of the pumps and upstream of the columns,
• a tubing of narrow diameter to minimize spreading for the chromatographic bands in the analytical path and of wider diameter to minimize the operation pressure drop in the preparative path,
• a second routing valve downstream of the columns,
• a detection appliance mounted downstream of said second routing valve,
• a system for the collection of fractions, and
• a back pressure regulator, which is common to the analytical and preparatory paths, and mounted downstream of the detection device but upstream of the system for collection of fractions.