Table 1 Short description and in-process control of a representative [¹¹C]acetate synthesis using a TRACERlab FX FE module

Pre-synthesis

Approximately 30 min before EOB

Check valve A (CV_A) was closed by helium overpressure from V5. The reactor was filled with MeMgCl THF solution and purged with argon. Finally the [¹¹C]CO₂ line was connected

Radiolabelling

EOB + 8 min

The [¹¹C]CO₂ line was positioned close to the product detector (B) so that a temporary increase in activity was observed. After the reaction an activity maximum was measured in the reaction vessel

Quench and wash

2–4 min^a

The reaction mixture was quenched (Vial 2) and washed with water (Vial 4). The check valves A and B were opened by closing V5 and applying a vacuum to the waste vessel. An increase in activity on the anion exchange cartridge was observed. A pressure increase in the waste vessel indicates that the washing step has been completed

Wash anion exchanger

60 s

To ensure that all by-products were separated, the anion exchanger cartridge was washed again with water from V6. A pressure increase in the waste vessel indicates that the washing step has been completed

Helium purge

30 s

Further purging with helium closes check valve B (CV_B)

Product extraction and degassing

90 s

By releasing the overpressure from the product vial, the check valve C (CV_C) was opened and the product was extracted from the anion exchanger with saline. The product was transferred into the citrate buffer solution and the by.product [¹¹C]carbonate was removed by helium bubbling

Filling

180 s

Filling