Rapid and simple determination of homovanillic acid in plasma using high performance liquid chromatography with electrochemical detection.

A rapid, yet highly reliable, procedure for determination of homovanillic acid (HVA) in plasma is described. After precipitation of proteins with perchloric acid, separation of sample components is directly achieved with high performance liquid chromatography on a reversed-phase column (C8), followed by quantitation based on electrochemical detection. The sensitivity of this method is 0.5 pmol/injection. Detector response is linear from the limit of detection to at least 0.5 nmol/injection. The intra-assay coefficient of variation is 2.2% in the concentration range of 50-150 pmol/ml plasma. The inter-assay coefficient of variation is 6.3%, based on determinations on 30 working days. A comparison of the present method and a specific gas chromatographic-mass spectrometric assay showed good agreement between the two procedures. One chromatographic run requires less than 16 min. for plasma and 10 min. for a standard.