<p>A method of conducting radiofluorination of a substrate, comprising the steps of: (a) contacting an aqueous solution of [18F] fluoride with a polymer supported phosphazene base for sufficient time for trapping of [18F] fluoride on the polymer supported phosphazene base; and (b) contacting a solution of the substrate with the polymer supported phosphazene base having [18F] fluoride trapped thereon obtained in step (a) for sufficient time for a radiofluorination reaction to take place; an apparatus for conducting radiofluorination; use of the apparatus; and an apparatus for production of a dose of a radiotracer for administration to a patient.</p>