Multiresidue analysis of beta-agonists in bovine and porcine urine, feed and hair using liquid chromatography electrospray ionisation tandem mass spectrometry

The use of beta-agonists as growth promoters in cattle breeding is forbidden in many countries for reasons of fair trade and consumer protection. In recent years the use of liquid chromatography (LC) tandem mass spectrometry (MS/MS) has been shown to be the method of choice for the control of beta-agonists. In this study an LC-MS/MS multiresidue analysis method is presented for trace analysis of 22 beta-agonists. A truly generic concept has been designed based on mixed-mode solid-phase extraction and positive electrospray ionisation LC-MS/MS operated in the multiple reaction monitoring mode. This method allows application to a wide variety of sample matrices such as urine, feed and hair, following minor modifications to the analysis procedure only. The method features fit-for-purpose sensitivity in urine as shown by CC alpha and CC beta values of less than 0.2 and less than 0.5 mu g/l respectively, for all beta-agonists studied (terbutaline and reproterol, less than 0.3 and less than 1.0 respectively). Similar but semiquantitative application to feed and hair showed CC beta values of less than 10.0 and less than 5.0 mu g/kg, respectively. A further simplification and improvement is demonstrated using Ultra Performance LC (UPLC (TM)) and fast-switching MS/MS. The successful validation of this method following the latest EU requirements and its application to real samples demonstrate that a new versatile tool has been achieved for veterinary control of beta-agonists.