US Patent 7958774 Device and method for sample preparation

A system and method for sample preparation and/or sample enrichment are provided. The system comprises the following components: a first switch element with a switch element input and at least two mutually exclusive switch element outputs and a second corresponding switch element with at least two mutually exclusive switch element inputs and a switch element output, the first and second switch elements being connected to control means for opening and closing the switch element inputs and switch element outputs; a first distributor element with at least three ports and a second distributor element with at least three ports; as well as a first separation column and a second separation column, the components being in such fluidic communication with each other that by means of different positions of the switch elements it is possible to configure at least two different fluidic paths in the system, wherein said different positions are achievable through the control means. The system allows, for example, the simple performance of the backflush process.