Comparison of fluorographic methods for detecting radioactivity in polyacrylamide gels or on nitrocellulose filters

The commercial fluorographic enhancers, En3Hance or Amplify, were not as efficient as 2,5-diphenyloxazole (PPO) for detecting radioactively labeled proteins in polyacrylamide gels or on nitrocellulose filters. For most of the X-ray films tested, optimal preexposure was essential to obtain maximum sensitivity in fluorography or indirect autoradiography using intensifying screens. The best results were obtained with nitrocellulose by saturating the filters with PPO. The minimum levels of 35S/14C that could be detected on filters by autoradiography or fluorography in a 24-h exposure were 4 X 10(2) or 1 X 10(2) dpm cm-2 respectively. For 3H these levels were, respectively, 20 X 10(3) or 0.5 X 10(3) dpm cm-2.