High Performance Liquid Chromatographic Determination of 11 Steroidal Hormones in Meat and Milk with Enzyme Hydrolysis of Sample

Smashed meat sample was extracted ultrasonically with acetonitrile,and the extract was evaporated to dryness and taken up with phosphate buffer.Phosphate buffer was added directly to milk sample without pretreatment.Enzymehydrolysis was then performed by incubation at 37 ℃ for 24 h after the addition of β-glucuronidase.The hydrolyzed solution was filtered and passed through the SPE microcolumn,which was eluted with acetonitrile.One mL of the eluate was taken for HPLC separation and determination,using Zorbax Extend C18 as the stationary phase and the mixed solution of KH2PO4 and CH3CN as the mobile phase in the linear gradient elution.Detection limit,recovery and precision of the method for determination of 11 different steroidal hormones were tested,and values of results found were in the ranges 0.009-0.020 mg·kg-1,51.0%-107.0% and RSD′s (n=6) 0.77%-6.42% respectively.