Rapid time-resolved fluoroimmunoassay for the screening of monensin residues in eggs Original Research Article

Polyether ionophores, such as monensin, are commonly used as feed additives in the poultry production. However, ionophore residues in foodstuffs may have adverse health effects on humans. In order to effectively implement residue control programmes in the European Union (Council Directive 96/23/EC), rapid analysis methods are required. A competitive time-resolved fluoroimmunoassay was developed for the determination of monensin residues in eggs. Prior to analysis, the residues were extracted from eggs with acetonitrile according to a simple protocol. The assay, which could be utilised in a quantitative or qualitative mode, was validated in compliance with Commission Decision 2002/657/EC. The detection capability of the assay was determined to be less than 2 μg kg−1. The intra-assay variations (n = 6) were below 10% and the interassay variations (n = 18) ranged between 10.3 and 13.9%. The mean recoveries (n = 6), established at three concentration levels, varied from 88.0 to 102.1%.