Veterinary Drugs Residue Methods


Category None
Drug Class Name Synthetic nonsteroidal estrogenic growth promoters
Method Title Determination and Confirmation of Diethylstilbestrol (DES) and Zeranol by GC/MS
Method Date 2004/11/10
Method Type Screening, Confirmatory, Quantitative
Scope and Application The method is applicable for screening/confirmation/quantitation of the synthetic nonsteroidal estrogenic growth promotersDiethylstilbestrol and Zeranol in ovine and bovine liver and muscle.
Method Summary Pieces of tissue (cut carefully to avoid fat) from thawed meat samples are homogenized in acetonitrile using a blender/grinder. The homogenate is centrifuged and the filtered supernatant thoroughly mixed with dichloromethane/hexane (1:4, v/v). The middle solvent layer (acetonitrile) is transferred into a scintillation vial. Centrifugation is repeated after more acetonitrile is added to the remaining two solvent layers (dichloromethane and hexane). The extra acetonitrile is also transferred into the scintillation vial and the contents evaporated to dryness. The residue is re-constituted in isopropanol:methanol (1:1, v/v) before adding 2N sodium hydroxide solution. The mixture is vortexed and loaded on clean-up catridges (TYPE AS). Following a series of elutions, the final eluate (methanol) is evaporated just to dryness before analysis by GC/MS. If not analysed as soon as possible, the extract must be stored in a freezer (for a maximum of 1 week) '
Applicable Concentration Range Diethylstilbestrol and Zeranol may be detected in ovine and bovine liver and muscle at the levels ≥ 0.5 µgkg-1 and ≥ 1.0 µgkg-1, respectively.
QC Requirements See attached SOP
Method Source USDA-FSIS
Method SOP PDF icon SOP