The present invention relates to a method and a device for the parallel study of chemical reactions in at least two spatially separated reaction spaces. In particular, the invention is suitable for reactions which are not constant volume reactions and/or for reactions in which fluid flows through at least two spatially separated reaction spaces are intended to be controlled together for all the reaction spaces, or for related subsets of them, in the most straightforward way possible.According to one embodiment, the device according to the invention for the parallel study of chemical reactions comprises at least the following components: (a) at least two spatially separated reaction spaces; (b) on the reaction space input side, at least one common educt feed for the reaction spaces according to (a); (d) on the reaction space output side, at least one connection per reaction space to at least one holding gas feed common to all the reaction spaces, or subsets of them; (e) on the reaction space output side, and downstream of the connection to the holding gas feed according to (d) in the product flow direction, at least one restrictor per reaction space.

Synthesis of chain molecules such as DNA is carried out in a conduit having an interior channel with an inlet end and an outlet end. At least one wall of the conduit is substantially transparent to selected wavelengths of light. Solid carrier particles are contained within the interior channel of the conduit. A plurality of controllable light sources are mounted at spaced locations along the length of the transparent wall of the conduit to allow selective illumination of separated sections of the particles within the conduit. When a light source is turned on, a photodeprotecting group is removed from the carrier particles in the section that is illuminated by the light source. A reagent containing a selected base is flowed through the conduit so that the base will attach to the carrier particles in those sections which have been exposed to light and deprotected. Reagents may be applied which subsequently again protect the bases followed by selective application of light to certain sections, removal of the deprotection group, and attachment of a new base, with the process repeated until desired sequences have been formed on the carrier particles at each of the separated sections in the conduit. The synthesized molecules may then be removed for direct use or further processing.