A simplified technique for the liquid scintillation measurement of radioactivity on paper chromatograms containing toluene-insoluble C14- and H3-labeled compounds

A convenient and relatively efficient technique was developed for the routine measurement of radioactivity distribution on one-dimensional paper chromatograms containing low amounts of H3- and C14-labeled compounds which are insoluble in the scintillation solvent toluene. A pilot strip, 2 cm wide, was cut out from the chromatogram and divided into 3 4 cm bands along the length of the chromatostrip. Each band was placed in a standard 20-ml screw-top glass vial. Methanol (0.2 ml) was added and the contents were shaken occasionally for 2 or 3 min. Both the methanol and filter paper band were flooded with 10 ml scintillation fluid and the contents were counted. This technique was found to be more satisfactory in terms of efficiency and reproducibility than several other methods tested.