Determination of Ionophore Coccidiostats in Feeding Stuffs by Liquid Chromatography-Tandem Mass Spectrometry - Part II. Application to Cross-Contamination Levels and Non-Targeted Feed

A fit to purpose multi-analyte method for the official control of six coccidiostats (monensin sodium, salinomycin sodium, narasin, lasalocid sodium, semduramicin sodium and maduramicin ammonium alpha) at cross-contamination concentration levels in poultry, cattle, pig and calf compound feed by liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed and in-house validated. The corresponding maximum levels have been recently introduced by European legislation. The method developed involved a simple extraction of the coccidiostats from the feed samples followed by centrifugation and filtration of the supernatants for all matrices. For calf feed an additional de-fattening step of the filtrated supernatants with n-hexane was necessary. The resulting supernatants were submitted to chromatographic analysis. The analytes were quantified by a modified approach of the standard additions technique applied to the extracts, hence allowing a workload comparable to matrix-matched standard calibration curves. A further simplification of this technique was reached by applying the same addition levels of the target analytes for different concentration ranging from 0.5× maximum level up to 2.5× maximum level (universal approach). The concentration independent intermediate precision expressed in terms of relative standard deviation varied between 3 and 12% (except for maduramicin ammonium alpha and semduramicin sodium up to 21%) and the recovery rates ranged from 80 to 111%, depending on the target analyte and matrix. The limits of detection (LOD) and limits of quantification (LOQ) were different for the various analyte/matrix/instrument combinations but all LOQs were in the 0.01¿0.65mgkg-1 range, hence well below the target concentrations of each analyte. Based on the obtained method performance characteristics the method is considered fit for the intended purpose.

VINCENT Ursula;  EZERSKIS Zigmas;  CHEDIN Mostafa;  VON HOLST Christoph; 

2010-11-18

PERGAMON-ELSEVIER SCIENCE LTD

JRC58534

0731-7085,   

www.elsevier.com/locate/jpba,    https://publications.jrc.ec.europa.eu/repository/handle/JRC58534,   

10.1016/j.jpba.2010.09.038,