A Simple Low-voltage Paper Electrophoretic Method for the Determination of Urinary Vanillylmandelic Acid (vma).

A simple and accurate method for the determination of urinary 3-methoxy-4-hydroxy-mandelic acid, vanillyl-mandelic acid (VMA), is described. The separation of VMA from all other phenolic acids in approximately 0.05 ml. untreated urine is achieved by using low-voltage paper electrophoresis with different buffer concentrations for the cathode and the anode. The concentration of the electrophoretically separated VMA is determined colorimetrically in the eluate. Values of excreted VMA in 24-hr. normal urine and those from subjects with pheochromocytoma differ considerably. We are now applying this new principle of “two solutions paper electrophoresis” for better separation of amino acids, proteins, and other biologic mixtures.