Veterinary Drugs Residue Methods


Category Resorcylic acid lactones, including zeranol
Drug Class Name Zeranol, a Synthetic nonsteroidal estrogenic growth promoters
Method Title Screening for Zeranol by ELISA
Method Date 2007/02/26
Method Type Screening
Scope and Application This method is useful for qualitative analysis of zeranol in liver and muscle tissue.
Method Summary Homogenized liver and meat tissue is extracted in distilled water with the liver homogenate further digested with Beta-glucuronidase. Ethyl acetate is added to both tissue homogenates that are then extracted by centrifugation. The organic layer is evaporated to dryness before reconstituting the residue in chloroform. Sodium hydroxide is then added and after further centrifugation, the upper aqueous layer is mixed with 90 percent acetic acid. Centrifugation is repeated after adding diethyl ether to the mixture. This is then frozen at - 25 degrees celcius for 60 min and later evaporated to dryness. The residue is reconstituted in a sample dilution buffer before analysis by ELISA. Absorbance is measured - within 60 minutes - at 450 nm against an air blank.
Applicable Concentration Range Zeranol may be detected in liver or muscle tissue at ≥ 0.5 µg kg -1 concentration level.
QC Requirements See attached SOP
Method Source USDA-FSIS
Method SOP PDF icon SOP