Determination of vanilmandelic acid

Abstract

Vanilmandelic acid (VMA) or 3-methoxy-4-hydroxymandelic acid is a major metabolite of epinephrine and norepinephrine. Pheochromocytomas, tumors of the chromaffin tissue of the adrenal medulla, are associated with the presence of greatly increased excretion of VMA. The first method for determination was developed by Armstrong and co-workers in 1957 using paper chromatography. Since then, several other techniques have been described including high and low voltage electrophoresis, gas chromatography, spectrophotometry, enzymology and to a lesser degree, isotope dilution.

Spectrophotometry has become the method of choice in screening purposes because of its simplicity and because it does not require any instrumentation which is not already present in the laboratory.

Commercial kits for VMA determination are presently being marketed. These kits should reduce the time spent on each assay so that results can be reported with minimal delay. This study investigated the methodology of the VMA-Skreen, a kit procedure, and correlated this kit method to a reference method, the Pisano method. The Pisano method was also used in correlation to the method presently used by the Youngstown Hospital Association. Better correlation was observed between the VMA-Skreen and the Pisano methods, indicating a closer relationship in methodologies.