Capturing [¹¹C]CO₂ for use in aqueous applications.

We present a simple method for trapping [(11)C]CO2 gas and releasing it into a buffered solution using an ion-exchange cartridge. Sodium hydroxide cartridges captured >99% of [(11)C]CO2 following NaOH activation. A sodium bicarbonate solution eluted >99% of trapped radioactivity. Trapping [(11)C]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.