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 β-zearalenol (β-ZAL), β-zearalanol (β-ZOL), α-zearalenol (α-ZAL), α-zearalanol (α-ZOL) and zearalanone (ZAN) in urine (human, bovine and swine) samples is proposed. The method comprises previous clean-up and pre-concentration on C18 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 β-ZAL, β-ZOL, α-ZAL, α-ZOL, ZAN and ZON in a linear range between 5 and 50 ng 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 (β-ZOL, α-ZAL, α-ZOL) and 1.4 ng mL−1 (β-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.