Abstract
A simplified and accurate assay method for measuring 3-methoxy-4-hydroxy mandelic acid (VMA) in human urine was established. The method is thought to be applicable to the assay of a large number of samples at one time. VMA concentration in human urine was determined spectrophotometrically after purification of the VMA and its conversion to vanilline. The extraction of VMA and vaniline from the medium into the organic solvent and their purification depend largely on pH, of which the indicator is an excellent reagent for the conversion of VMA to vanilline. The normal value of VMA in the urine of eight healthy young resting males (20-24 years old) was found with this method to be 41.4± 21.3 moles/ min (the mean±S.D.).
