Determination of apovincaminic acid in human plasma by gas-liquid chromatography

High-resolution capillary gas-liquid chromatography (GLC) and highly sensitive and selective nitrogen-phosphorus flame ionization detection were applied for the detection of apovincaminic acid (AVA), the main metabolite of the cerebral vasodilator vinpocetine in human plasma. AVA was recovered from plasma by ion-pair extraction and determined by GLC as its methyl ester after derivation with diazomethane. An acid-base washing technique was used in order to reduce the contamination of GLC samples by material of endogenous origin to a minimum. The lowest detection limit of the method is 2 ng of AVA per ml of plasma.