Stability characterization of aryl fluorosulfates in vitro and in vivo. (a) Stability of 1 (5 mmol L−1) in phosphate buffers, water and MeCN at room temperature over a course of 24 h. Percentage of remaining materials was quantified by HPLC (n = 3). (b) Stability of 1 (5 mmol L−1) in pH 7.4 buffer in the presence of nucleophilic amino acids and reduced glutathione (5 mmol L−1), respectively, at room temperature (n = 3). (c) Stability of 1 (5 mmol L−1) under physiological conditions, pH 7.4, 37 °C (n = 3). (d) PET images (60 min post-injection) of healthy mouse dosed by (S)-[18F]24 demonstrating its in vivo stability.