Modification of the Pisano method for vanilmandelic acid using high pressure liquid chromatography

A method for the measurement of urinary vanilmandelic acid (VMA) is described based on a modification of the colorimetric procedure of Pisano. VMA is oxidized to vanillin with subsequent measurement of the vanillin by high pressure liquid chromatography with electrochemical detection (LCEC). The technique has been successfully applied to a number of human and animal urine samples. Urinary VMA values obtained by the LCEC method are in good agreement with those determined by the method of Pisano. The new method is both more selective and more sensitive than the colorimetric procedure.