摘要：A method is described for the counting of C 14 biological materials on paper chromatograms. Paper sections are placed in counting vials and are extracted by the solubilizing agent, hyamine. Scintillation solvent is then added, and the samples are counted by a liquid scintillation spectrometer. Absolute radioactivity of each spot can be obtained by any of the following three correction methods. One method involves the dilution of the sample by scintillator solvent, the other uses an internal standard, and the last method involves correction of the observed radio-activity by the counting efficiency obtained from the ratio of counts in two separate windows of the spectrometer. Any of the three methods will give quantitative data if the extraction of the sample from the paper by a solubilizing agent is over 80%. The methods have been applied to the counting of various C 14 amino acids and C 14 sugars on paper sections with excellent recovery in radioactivity and reproducibility.