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A fast and sensitive high-performance liquid chromatographic method has been developed for the determination in human plasma of MHPG (3-methoxy-4-hydroxyphenylethylenglycol) and VMA (vanillyl mandelic acid), the main metabolites of epinephrine and norepinephrine. Analyses were carried out at 325 nm while exciting at 285 nm on a reversed-phase column (Atlantis C18, 150 mm x 4.6 mm I.D., 5 mu m) using a mobile phase composed of 2% methanol and 98% aqueous citrate buffer at pH 3.0. A careful solid-phase extraction procedure, based on mixed-mode reversed-phase - strong anion exchange Oasis cartridges (MAX, 30 mg, 1 mL), was developed for the pre-treatment of plasma samples. Extraction yields were satisfactory, always higher than 90%. Calibration curves were linear over the 0.2-40.0 ng mL(-1) concentration range for MHPG and over the 0.5-40.0 ng mL(-1) concentration range for VMA. The method was successfully applied to plasma samples of former drug users undergoing detoxification therapy and subjects "at risk" of developing drug addiction. (C) 2008 Elsevier B.V. All rights reserved.