Determination of Homovanillic Acid in Human Plasma Using HPLC with Electrochemical Detection and Automated Solid Phase Extraction

Abstract

An isocratic HPLC method with electrochemical detection for the quantification of homovanillic acid (HVA) is described. The method included automated solid phase extraction on C-₁₈-reversed phase material, followed by separation on a 3-μm Nucleosil 100 C₁₈ column (250 mm × 4.6 mm I. D.) with a 100 mM citric acid solution (pH 6.6) containing 4% acetonitrile (v/v) as eluent at a flow rate of 0.6 ml/min. Isovanillinic acid served as internal standard. Extractability of both analytes was ca. 80 %. After extraction of 1 ml of plasma, coefficients of variation of replicate analyses were below 10 % in the naturally occuring concentration range.