Abstract: According to the present invention there is provided a method of molecule recovery using an assembly which comprises a first flow cell (2) which comprises comprising first ligands (4) which can bind to molecules, and a conduit which can selectively fluidly connect the first flow cell to a collection reservoir (39); the method comprising the steps of (a) flowing a sample fluid along the conduit into the first flow cell (2); (b) flowing a buffer fluid through at least a portion of the conduit, without flowing any of the buffer fluid through the first flow cell (2) so that sample fluid is maintained in the first flow cell (2) but said at least a portion of the conduit is cleaned by the buffer fluid; (c) flowing a buffer fluid through the first flow cell (2) to flush the sample fluid out of the first flow cell (2); (d) lowing a fluid through the first flow cell (2), along the conduit, and into the collection reservoir, so that molecules of the sample fluid which were bound to first ligands (4) and which have beco