A rapid method for the determination of lasalocid in animal tissues and eggs by high performance liquid chromatography with fluorescence detection and confirmation by LC-MS-MS

A simple and rapid method has been developed for the extraction of lasaloci d from chicken muscle, eggs and liver and kidney from chicken, pig, sheep a nd calf. This method allows the screening of a large number of samples, i.e . 30-40 within a working day, and has an overall analysis time of 90 min. L asalocid standard solution can be detected at 1 ng ml(-1) by both HPLC-fluo rescence (HPLC-F) and LC-MS-MS; the limit of quantification in fortified sa mples by the described method is 1 ng g(-1). Results show good repeatabilit y and mean 'spiked' recoveries by HPLC-F in the range of 10 to 200 ng g(-1) (ppb) of 103, 87, 107, 97, 97, 103, 93, 109 and 100% in chicken muscle, ch icken liver, egg, pig liver, pig kidney, sheep liver, sheep kidney, calf li ver and calf kidney, respectively. For concentrations between 1 and 6 ng g( -1) of spiked lasalocid in eggs and chicken liver by LC-MS-MS, the average recoveries were 76 and 59%, respectively.