Lc 20at pump

[¹⁸F]FB-Tz was synthesised using the GE FASTLab™ automated radiosynthesis platform via reductive amination radiochemistry between precursor 3 and 4-[¹⁸F]fluorobenzaldehyde ([¹⁸F]FBA) (Scheme 1). We described the automated procedure elsewhere;^{21 (link)} in brief, aqueous [¹⁸F]fluoride was dried for the radiosynthesis of [¹⁸F]FBA from the 4-formyl-N,N,N-trimethylanilinium trifluoromethansulfonate precursor and used without further purification. Compound 3 was dissolved in acetonitrile by the addition of triethylamine to quench the TFA-salt, then added to the vessel containing [¹⁸F]FBA. The imine intermediate was formed at 65 °C for 15 min, before the reaction mixture was flowed through a cartridge containing solid-supported cyanoborohydride to reduce the imine to the secondary amine. [¹⁸F]FB-Tz was purified by semi-preparative HPLC (Shimadzu LC20-AT pump attached to a custom-built system, equipped with an Agilent Eclipse XDB-C18, 5μ (250 × 9.4 mm) column. The mobile phase was 20% EtOH/80% sodium phosphate (58 mM, pH 2.4) at a flow rate of 4 mL min⁻¹) and the desired product was diluted in water (30 mL), trapped on a tC18 SPE cartridge, dried under a flow of nitrogen and eluted in EtOH for biological use. [¹⁸F]FB-Tz was characterised by radio-HPLC to determine its identity (by comparison to an authentic reference standard) and purity (Fig. 2B and C).