Determination of zearalenone and its metabolites in urine samples by liquid chromatography with electrochemical detection using a carbon nanotube-modified electrode

A simple and sensitive method for the separation and determination of zearalenone (ZON) and its secondary metabolites, namely beta-zearalenol (beta-ZAL), beta-zearalanol (beta-ZOL), alpha-zearalenol (alpha-ZAL), alpha-zearalanol (alpha-ZOL) and zearalanone (ZAN) in urine (human, bovine and swine) samples is proposed. The method comprises previous clean-up and pre-concentration on C-18 adsorption cartridges of the analytes followed by liquid chromatographic separation and direct electrochemical detection at +0.85 mV using a carbon nanotube-modified glassy carbon electrode (CNT-GCE). This method allows the determination of beta-ZAL, beta-ZOL, alpha-ZAL, alpha-ZOL, ZAN and ZON in a linear range between 5 and 50ng mL(-1), with relative standard deviation values lower than 6.9% (intra-day) and 7.1% (inter-day), in all cases. Detection limits ranging between 1.3 ng mL(-1) (beta-ZOL, alpha-ZAL, alpha-ZOL) and 1.4 ng mL(-1) (beta-ZAL, ZAN, ZON) were achieved. The usefulness of the proposed method was demonstrated by the analysis of spiked and natural samples of human, bovine and swine urine samples. (C) 2008 Elsevier B.V. All rights reserved.