Quick liquid exchange in liquid chromatography

A liquid chromatographic (LC) system comprising a liquid chromatography pump comprising at least one pump head comprising a primary pump head and a secondary pump head, each comprising a syringe-like cylinder body having an inner wall surface and a plunger translatable through the cylinder body leaving an interspace between the inner wall surface and the plunger when the plunger is translated through the cylinder body, an upstream inlet valve configured to allow liquid into the cylinder body and a downstream outlet valve configured to allow liquid out of the cylinder body, the downstream outlet valve of the primary pump head being connected to the upstream inlet valve of the secondary pump head, and wherein the LC system further comprises at least one liquid-exchange pump connected either to the upstream inlet valve of the primary pump head or to the downstream outlet valve of the secondary pump head, wherein said at least one liquid-exchange pump is configured for exchanging a liquid present in the cylinder bodies of the primary and the secondary pump heads with another liquid by purging through the interspaces left between the inner wall surfaces of the cylinder bodies and the plungers, respectively.