Flow injection fluorimetric determination of L-dopa and dopamine based on a photochemical inhibition process

摘要

An automatic procedure has been developed for the determination of L-dopa and dopamine.It is based on the strong inhibition of the photochemical reaction between thionine blue and ethylenediamine-tetraacetic acid by these catecholamines.The proposed flow-injection method allows for the fluorimetric determination of L-dopa in the range of 1.9-98 mu gmL-1 and that of dopamine in the range of 1.9-75 mu gmL-1 with a sampling frequency of 35 samples h_1.The method was applied successfully to the determination of dopamine in pharmaceutical preparations.