[Simultaneous determination of residues of six zeranols in eggs by high performance liquid chromatography with immunoaffinity cleanup column].

An immunoaffinity cleanup-high performance liquid chromatography (IAC-HPLC) method was established for the simultaneous determination of residues of six zeranols (alphazeranol, beta-zeranol, alpha-zearalenol, beta-zearalenol, zearalanone and zearalenone) in eggs. The enzymolyzed samples were extracted with methyl tert-butyl ether, and subsequently reextracted with a sodium hydroxide solution. After the pH value was adjusted to 7, the extract was cleaned up on an immunoaffinity column. The chromatographic separation was performed on an Agilent Eclipse XDB-C18 column (150 mm x 4.6 mm, 3.5 microm) using methanol-acetonitrile-water (50:15:35, v/v/v) as the mobile phase at a flow rate of 1.0 mL/min and ultraviolet (UV) detection at 270 nm. The six zeranols had good linear relationships in the range of 0.01-0.2 mg/L with the correlation coefficients not less than 0.999 8; the recoveries of six target compounds at different spiked levels ranged from 73.2% to 95.7% and the relative standard deviations were less than 8%. The limit of detection (S/N > or = 3) was 1.0 microg/kg for each zeranol. The method is stable, reliable and accurate, and can be used for the determination of trace residues of the six zeranols in eggs.