An Efficient Method for Enhancing the Reactivity and Flexibility of [ 18 F]Fluoride Towards Nucleophilic Substitution Using Tetraethylammonium Bicarbonate

The standard method used to generate reactive [ 18 F]fluoride for [ 18 F]radiolabelling is to trap it on an anion‐exchange cartridge then elute it with a basic aqueous solution, which is then subjected to azeotropic evaporation to remove water. We have now developed a method through the use of tetraethylammonium hydrogen carbonate in which we can obtain efficient recovery of [ 18 F]fluoride (up to 99 %), remove the requirement for the time‐consuming and inefficient azeotropic evaporation process and produce a reactive [ 18 F]fluoride that can undergo a wide range of aliphatic and aromatic [ 18 F]nucleophilic substitutions in up to 93 % radiochemical conversion at end‐of‐synthesis in the presence or without water.