Reduction of [11 C]CO2 to [11 C]CO using solid supported zinc.

A new method for the reduction of no-carrier-added [11 C]carbon dioxide into [11 C]carbon monoxide ([11 C]CO) is described, in which the reductant (zinc) is supported on fused silica particles. Using this setup, which allows for a reduction temperature (485°C) well above the melting point for zinc (420°C), radiochemical yields of up to 96% (decay-corrected) were obtained. A slight decrease in radiochemical yield was observed upon repeated [11 C]CO productions (93 ± 3%, n = 20). The methodology is convenient and efficient and provides a straightforward path to no-carrier-added production of [11 C]CO.