GBq, removing the possibility of improving the radiotracer concentration by starting with synthesis with a higher amount of radioactivity. More than 20 mL of PBS buffer was required to elute the radiotracer from the MCX cartridges and this large volume resulted in a radiotracer solution of < 10 MBq/mL at end of synthesis (EOS). In order to avoid a manual reformulation, we sought to improve the radiotracer concentration by optimizing [ 18 F]FSPG isolation and collection.