Investigations to the synthesis of n.c.a. [¹⁸F]FClO₃ as electrophilic fluorinating agent

An approach to synthesize the electrophilic fluorinating agent no-carrier-added (n.c.a.) [¹⁸F]perchloryl fluoride ([¹⁸F]FClO₃) in superacidic media in the presence of KClO₄ or anhydrous perchloric acid starting from [¹⁸F]fluoride was demonstrated in this study. However, the radiochemical yields were low (1–6%) and poorly reproducible. Fluorosulphonic acid proved to be an essential intermediate as revealed by non-radioactive experiments. A key problem in the preparation of [¹⁸F]FClO₃ is the assumed kinetic inhibition due to the unfavourable stoichiometric ratio of the ClO₄ moiety to [¹⁸F]HSO₃F.