Determination of four nitroimidazoles in poultry and swine muscle and eggs by liquid chromatography/tandem mass spectrometry

A rapid method is presented for the determination of 4 nitroimidazoles in poultry and swine muscle and eggs by liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). Samples were extracted with acetonitrile, then evaporated the organic phase. After filtration, the extract was directly injected into the LC/ESI-MS/MS system. The LC separation was made on a C8 column by applying a gradient composed of water and acetonitrile. Overall average recoveries ranged from 50-86% for egg, 66-115% for poultry muscle, and 79-111% for swine muscle. The decision limits ranged from 0.05-0.25 microgram/kg for egg, 0.07-0.27 microgram/kg for poultry muscle, and 0.07-0.26 microgram/kg for swine muscle; and detection capabilities ranged from 0.51-0.68 microgram/kg for egg, 0.41-0.75 microgram/kg for poultry muscle, and 0.53-0.78 microgram/kg for swine muscle.