β‐agonists in animal feed III: Optimization of the clean‐up and the end‐determination step

Abstract

This study represents the second part of an interlaboratory study intended to develop an official modular Community confirmatory method for the detection of β‐agonists in animal feed. Homogeneous pools of primary extracts were prepared by means of an extraction module based on the conclusions of a previous part of this work. The primary extracts were further processed by four laboratories each using a different clean‐up scheme. The final extracts thus obtained were cross‐distributed between the same laboratories and measured either by GCMS or HPLC. Two laboratories (B and D) applied separate clean‐up schemes for clenbuterol and salbutamol. All clean‐up schemes for clenbuterol were found to be compatible with all end‐determination steps. In contrast, for salbutamol clean‐up method D was found not to be compatible with the end‐determination steps applied by laboratories B and C. The results of this study have clearly demonstrated that the clean‐up methods for both clenbuterol and salbutamol applied by laboratory B yielded superior recoveries with an acceptable standard deviation. Therefore, in conclusion to this study, the participating laboratories recommend the clean‐up schemes applied by laboratory B to serve as part of the official Community confirmatory method.