Methods and apparatus for facilitating the synthesis of compounds in a nonflow-through device are presented. Application of the nonflow-through methods and microfluidic devices to the synthesis of radiolabeled compounds is described. These methods and apparatus enable the introduction of a pressurized gas through a tangential slit into a vortex reactor of the nonflow-through device, while one or more liquids are delivered to the reaction chamber through the same or different inlet ports. The introduction of the pressurized gas produces a cyclonic motion of the mixture within the reactor. Such a mechanism may be used to facilitate the evaporation of various liquids within the reactor at lower temperatures, thus reducing the production of unwanted byproducts that are associated with the use of high temperatures. In addition, thorough mixing of various liquids may be effected rapidly while allowing chemical reactions to take place efficiently within the vortex reactor.