Fig. 3. (A) Dependence of oxidation (% of the oxidized form in the reaction mixture) on the ratio of water-to-acetonitrile (water%) for peptide [¹⁸F]6, during incubation with a solution comprising of 25, 60, 75 and 95% (v/v) of water at 60 °C (n = 1). Radio-HPLC chromatograms (for HPLC method, see ESI Table S2†) of the oxidized forms of the peptide cycloadducts (B) [¹⁸F]6t_R = 17.2 min, (C) [¹⁸F]5t_R = 18.5 min and (D) [¹⁸F]7t_R = 18.6 min after incubation in ≥95% (v/v) water at 60 °C yielding full conversion.