Thin Layer Chromatographic Separation and Quantitation of L-Dopa and L-Tyrosine in Mixtures

A new TLC separation and quantitation method for L-tyrosine and L-Dopa mixtures was developed. The minimum tyrosine and Dopa quantities which can be measured by this technique are 0.7 and 1.5 μg respectively. The method may be used to measure the kinetic parameters of polyphenoloxidase as well as to trace the enzyme catalyzed conversion of L-tyrosine into L-Dopa. For a set of 20 measurements the maximum difference between any two measurements of spot areas was found to be 3 mm (4.5%) for L-Dopa (4 μg) and 2mm (5.6%) for L-tyrosine (1μg) .