(EN) The present invention provides a chemical synthesis apparatus comprising a plurality of reagent inputs (2) and a solid support input (1). Each input (1, 2) is connectable to a main fluid pathway via a respective switchable valve (3). The apparatus further includes a reaction chamber (4) fluidly connectable to the main fluid pathway by a respective switchable valve (3) downstream of the inputs (1, 2). The reaction chamber (4) further includes an outlet downstream of a barrier (5) arranged to prevent passage of said solid supports but allows passage of unbound molecules.
