Determination of lasalocid in eggs using liquid chromatography–electrospray mass spectrometry

Abstract
A method is presented for the determination of the polyether ionophore, lasalocid, in eggs. Samples are extracted under acidic conditions using acetonitrile and the extracts are cleaned up using a simple liquid–liquid extraction step. Lasalocid is detected and quantified using liquid chromatography–electrospray mass spectrometry on a quadrupole bench-top instrument. The technique is highly sensitive, with a detection limit of about 0.5 ng g–1 of lasalocid in homogenized egg samples.