Methods
The [11C]CH4 exhaust from a GE FxMeI instrument was linked to an apparatus comprising a P2O5 trap, a CoF3 column inside a tube furnace, and a cold-bath for trapping any HF and another for [11C]CHF3 (Figure). Flows were controlled by 3-way valves. Radioactivity transfers were monitored by pin-diode radiodetectors.