Evaluation of β-agonists in blood meal: Validation of determination method and potential pathway for reentry into the environment.

β-agonists, which have been illegally used in animal production in some countries, can induce bioaccumulation when blood is converted by rendering into blood meal. Unfortunately, available data on this topic are scarce, which result in lack of risk assessment. Therefore, in this research, a method for simultaneous determination of 22 β-agonists in blood meal by liquid chromatography coupled with tandem mass spectrometry using isotope dilution was developed. The recoveries of the developed method ranged from 68.6% to 118.8% with RSD at below 20%. the limit of detection (LOD) is blew 1 μg/kg. The change in agonist form added and incurred blood into blood meal and long stability of β-agonist in blood meal were studied. Then, we analyzed blood meal for 22 agonists using this method. The results suggest blood meal is a possible pathway for agonist reentry into animals. Potential risks of agonist residues in blood meal were examined. This study is the first to explore source of β-agonist residues in blood meal, change in processing produce and stability in stored stage.