Rapid radiochemical and chemical quality control of [11C]putrescine

A short (4.6 x 50 mm) cation exchange column was used in conjunction with conductivity and radioactivity detectors to determine the radiochemical purity (> 99%) and specific radioactivity (0.5-1.0 Ci/mu mol) of [1-11C]putrescine prepared via Michael addition of [11C]cyanide to acrylonitrile. The absence of acrylonitrile, a rodent carcinogen, from the final preparation was verified at the 50 ng level capillary vapor-phase chromatography (VPC) using a nitrogen-phosphorus detector. Routine VPC analysis using a Poropak Q column and flame ionization detection showed that preparations contained no more than 1 microgram of acrylonitrile.