Abstract: This invention concerns a method, devices, instrument and program for extraction an ingredient from a liquid sample by bidirectional transfer of an aliquot of fluid between compartments, the method can be applied to a wide variety of laboratory techniques such as; solid phase extraction by filter disc, column chromatography, magnetic separation, diagnostic tests and others, the system is suitable for single or multi sample handling, manual operation or integrated into an automated system, can be used in a lab or in field.