Determination Of β₂-agonists Residues In Pork

β2-agonists are synthetic phenethanolamine compounds as bronchodilatory and obstructive pneumonitis agents in human and veterinary medicine. However, these drugs are often misused as growth promoters for their function in growth rates enhancement and feed efficiently. Meat products coming from treated animals might be a potential threat for consumer health and cause headache, chest tightness, nausea and other adverse reactions. So the use ofβ2-agonists as growth promoters in cattle is banned in the EU and our country. In this research, confirmatory method of ultra performance liquid chromatography/mass spectrometry/mass spectrometry (UPLC-MS/MS) and screening method of surface plasmon resonance (SPR) biosensor method were studied.UPLC-MS/MS method:After enzymatic hydrolysis, a 2.0 g homogenized pork sample was extracted, with perchloric acid-methanol (9:1, v:v) to precipitate protein, and then cleaned by mixed-mode Bond Elut Plexa PCX solid phase extraction (SPE) cartridges. Finally, the evaporated extract was reconstituted to 2.0 mL with initial mobile phase. The analytes were determinated by ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS-MS). Results indicate that the method is effective to reduce ion suppression phenomena. Recoveries of the threeβ2-agonists in most cases were better than 85% with relative standard deviations between 2.25 and 10.62%. The limits of detection (LOD) were 0.07-0.12μg/kg. The limits of quantitation (LOQ) ranged from 0.22-0.38μg/kg.SPR biosensor method:After extraction with perchloric acid, pork sample was cleaned by ethyl acetate and analyzed by SPR-2004 biosensor. Rac antibody and Rac derivative were fixed to the chip surface successively in order to optimize SPR detection method. In addition, regeneration solution was also was optimized in order to reduce chip memory effect. The limit of detection (LOD) was 0.60/μg/kg for pork samples. Recoveries of Rac were higher than 80% with relative standard deviations below 10%. This method was simper and rapid. The detection time was only 5 minutes. Compared with ELISA, this method was fast and did not require labeling for sample. Although the same pretreatment was applied for both the UPLC-MS/MS and the biosensor, the biosensor was proved little matrix interference by constructing pure solution and matrix-match calibration curves. Compared with other reports for detection Rac residue using SPR biosensor, SPR-2004 biosensor has minimal matrix interference and cost effective. In conclusion, the proposed biosensor is suitable for use as a practical screening method for the detection of Rac residue in pork and other meat products by food regulatory authorities and food industries.In conclusion, abilities of resisting matrix effect, the recoveries, precision, and sensitivity of the two residues detection methods ofβ2-agonists in pork in this study were also good. UPLC-MS/MS method was appropriate for confirmatory analysis. SPR biosensor method was perfect for rapid screening for a large number of samples detection in supermarket, food factory and food regulatory authorties.