A simple and rapid method for estimating 3-4-dihydroxyphenethylamine (dopamine), 3-4dihydroxyphenylalanine (dopa) and homovanillic acid (HvA) with “two solutions paper clectrophoresis

An easy procedure for the estimation of 3,4-dihydroxyphenylalanine (dopa), 3,4-dihy-droxyphenethylamine (dopamine), and homovanillic acid (HVA), besides 3-methoxy-4-hydroxymandelic acid (VMA), by means of the “two solutions paper electrophoresis” (1) is described. Increased amounts of these phenolic compounds were found by this method in the urine of a patient with neuroblastoma, and the case report is presented. I N PATIENTS with neuroblastoma, increased excretion of catecholamines and their metabolites has been described many times, beginning with Mason et al. in 1957 (2), and their diagnostic value has been emphasized. Furthermore, their rate of excretion is considered a good criterion in evaluating the follow-up after surgery or irradiation (3-5). There exist well-established methods for the detection of these sub-stances: 3-Methoxy-4-hydroxymandelic acid (vanillylmandelic acid, VMA) can be estimated by high-voltage (6) and low-voltage electro-phoresis (7), both requiring previous ethylacetate extraction of the urine. Ilomovamilic acid (HVA) can be estimated by 2-dimensional chromatography (8), which also requires ethylacetate extraction of the urine. 3,4-I)ihydroxyphenylalaiiine (dopa) and 3,4-dihydroxyphenethyl-amine (dopamiiie) do not enter the extract and have to be isolated by adsorption on ion exchange columns (9) ; the effluents of the column are subjected to 2-dimensional chromatography and the spots localized by applying the trihydroxyindol reaction for fluorescence