Determination of the specific radioactivity of amino acids by a combination of thin-layer chromatography and...

A new method for the analysis of the specific activity of amino acids is described. The analysis is carried out by thin-layer chromatography of the dansylated amino acids, computerized fluorescence evaluation and activity measurement by quantitative autoradiography. Quantitative evaluation of the autoradiographs is achieved by careful calibration of the X-ray film blackening. As shown for 14C-labelled phenylalanine and tyrosine, the method allows the simultaneous determination of the specific activity of 22 amino acids. About 10(-13) mol of an amino acid with a specific activity of less than 5 GBq/mmol can be detected and measured by this method.