Determination of residual β-agonists in beef by UPLC-MS /MS

Objective: To develop a UPLC- MS /MS analysis method for the determination of 9 beta- agonists,so as to provide data support for guaranteeing food safety. Methods: The samples were digested with β- glucuronidase for 4 hours,and the impurities were precipitated with perchloric acid; after adjusting the pH value,the solution was purified with MCX solid phase extraction column,dried by nitrogen and reconstituted with formic acid solution. UPLC- MS /MS analysis was performed. The separation was carried out on a Wsters BEH C18( 50 mm ×2.1 mm,1. 7μm) column using acetonitrile with 0. 1% formic acid( A)- 0. 1% formic acid solution( B) with gradient elution( 0-1 min,5%A maintained;1-3 min,5%A linear change to 50%-A;3-4 min,50%A linear change to 60%A; 4- 5 min,60% A linear change to 99% A; 5- 5. 5 min,99% A linear change to 5% A; 5. 5- 7. 5 min,5% A maintained). The flow rate was 0. 4 mL · min- 1,the column temperature 30 ℃,the injection volume 10 μL.Results: Excellent linear relationship was obtained from the additive concentration of 0. 5 μg·kg- 1to 10. 0 μg·kg- 1for the nine β- agonists( correlation coefficient r≥0. 9990),the recoveries ranged from 62. 7% to 107. 9% at the higher concentration; the lower limit of quantification( LLOQ),defined as the lowest concentration given the signal- to- noise ≥10∶ 1,was less than 0. 5 μg·kg- 1. Conclusion: The methodology validation shows that the established method is specific,simple,accurate,and rapid,which can be used to determine β- agonists in beef.