Capturing [¹¹C]CO₂ for use in aqueous applications

We present a simple method for trapping [¹¹C]CO₂ gas and releasing it into a buffered solution using an ion-exchange cartridge. Sodium hydroxide cartridges captured >99% of [¹¹C]CO₂ following NaOH activation. A sodium bicarbonate solution eluted >99% of trapped radioactivity. Trapping [¹¹C]CO₂ directly in small volumes of several solutions was less effective than cartridge methods. The recommended methods allow for fast and simple production of highly concentrated carbon-11 containing aqueous solutions for use in filling phantoms, calibrating detectors, or (bio)geochemical experiments. - Highlights: • An ion exchange resin can trap [¹¹C]CO₂ gas and release it with saturated bicarbonate. • Elution from cartridge requires as little as 300 µL volume, with eluant at pH=10. • SPE trap-and-release provided better results than trapping in solution