Method of operating a liquid chromatography arrangement, a liquid chromatography arrangement, and a chromatography system

A method of operating a liquid chromatography arrangement,

• the liquid chromatography arrangement comprising:
• a solvent pump arranged to flow a liquid solvent over a liquid chromatography column;
• a restrictor arranged to restrict the liquid solvent from leaving the liquid chromatography column;
• and
• a liquid pump arranged to provide liquid flow between the liquid chromatography column and the restrictor,
• the method comprising:
• flowing the liquid solvent through the liquid chromatography column using the solvent pump;
• and
• controlling a liquid pressure within the liquid chromatography column by providing a liquid flow between the liquid chromatography column and the restrictor using the liquid pump,
• wherein the pressure within the liquid chromatography column is varied over a period of time independently of a flow rate through the liquid chromatography column by controlling the liquid flow between the liquid chromatography column and the restrictor using the liquid pump.