Analytical methods for the determination of zeranol residues in animal products: a review

Analytical methods for zeranol residues are reviewed. Zeranol was a widely used as an anabolic promoter, and it could give rise to very low residues in the edible tissues of food animals. Zeranol was officially banned in Europe due to safety concerns because of its potential carcinogenic and endocrine-disrupting biological activity. A few analytical methods for determination of zeranol are reported in the literature and most of the methods such as thin-layer chromatography (TLC), gas chromatography-mass spectrometry (GC/MS), high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC/MS) and immunoassay are reviewed in this paper. Specific aspects of analysing zeranol such as sample selection, sample handling, method selection and chromatographic conditions are discussed. The instrumental methods such as LC/MS and GC/MS provide sensitive and specific techniques, but are very laborious and expensive. These methods are suitable for confirmation but not for screening of large numbers of samples. A rapid, sensitive and specific assay is needed to detect positive samples in routine analysis, and immunoassay offers practical advantages over the conventional instrumental methods in rapid analysis of zeranol residues. Immunochemical methods such as enzyme-linked immunoabsorbant assay (ELISA) are simple, rapid and cost-effective, with adequate sensitivity and specificity to detect small molecules. This review can be considered as a basis for further research aimed at identifying the most efficient approaches for the analysis of zeranol.