Determination of urinary 3-methoxy-4-hydroxymandelic acid (vanillylmandelic acid) by paper electrophoresis.

called vanillylmandelic acid (VMA), in urine has recently come into use as a confirmatory test for pheochromocytoma (1-6). Armstrong and his associates (1, 2, 7) discovered that this phenolic acid occurred in small amounts in normal human urine and in elevated concentrations in pheochromocytoma. As a result of their observations (1, 2) and especially of those by others in related investigations (8-11), VMA was shown to be one of the major metabolites in body tissues of epinephrine and norepinephrine. Thus, urinary VMA level is a good index of catecholamine production in the body. Other investigators (3-6) have confirmed the findings of Armstrong and his group (1, 2). For the measurement of VMA, Gitlow et at. (6) and Robinson and associates (5) modified the Armstrong two-dimensional paper chromatographic method (1, 2, 7). Studnitz and Hanson (3, 4) based their separation on the use of high-voltage paper electrophoresis. We were interested in measuring this phenolic acid by combining Gitlow ‘s (6) conditions for hydrolysis and extraction of urine with a modification of the Studnitz-Hanson (4) electrophoresis and elution