A procedure is described for the simultaneous determination of twelve acidic and alcoholic metabolites of trace and catecholic biogenic amines in plasma, cerebrospinal fluid and urine by capillary column gas chromatography--high-resolution mass spectrometry. Protein precipitation with sulphosalicylic acid, derivatization with two different reagent systems, final sample clean-up with a buffer wash and a program for automatically changing the reference mass of the mass spectrometer to suit each group of compounds as they are eluted from the column, are the main novel features of the procedure. A brief description of the synthesis of the deuterium-labelled internal standards is provided. The procedure is applied to biological samples and a comparison to reported values is given.