Radioactivity was measured in a CRC -25R dose calibrator (Capintec Inc.). The automated radiosynthesis platform used in the study was the GE FASTlab™ (GE Healthcare). All experiments were performed within a lead castle made of 50 mm lead bricks. All FASTlab consumables were obtained from GE Healthcare. 'Short tubing' refers to; Assembled Tubing Short PET, PART #: 1135059 (14 cm). 'Long tubing' refers to Assembled Tubing Long PET, PART #: 1135058, (42 cm). [ 18 F]FSPG precursor 2 was obtained from ABX GmbH, Radeberg, Germany. QMA light SepPak cartridge, MCX SepPak cartridges and Alumina light SepPak cartridge were purchased from Waters. Hypercarb cartridge were purchased from Thermo Fisher.