The simultaneous determination of the ionophore antibiotics in animal tissues and eggs by tandem electrospray LC-MS-MS

A method has been developed for the simultaneous extraction and determinati on of the four most currently used lonophore antibiotics (lasalocid, monens in, narasin and salinomycin) by LC-MS-MS from different animal tissues and eggs. Results show good repeatability. and mean spiked recoveries for lasal ocid, monensin, narasin and salinomycin in animal livers are in the average range 93-103, 96-103, 93-102 and 97-106%, respectively, and in eggs the me an spiked recoveries are 101, 103, 98 and 102% for lasalocid, monensin, nar asin and salinomycin, respectively. The detection limit is at 1 ng ml(-1) f or all the named ionophorous compounds. A quantitation level of 50 ng g(-1) for lasalocid, monensin at 2.5 ng g(-1), and 10 ng g(-1) for narasin and s alinomycin is achieved which represents half the action limit prescribed by the UK Regulation in compliance with the European Council Directive 96/23/ EC. A high throughput of samples is achievable using this method which allo ws the analysis of 30-40 samples by one analyst in a day. (C) 2001 Elsevier Science Ltd. All rights reserved.