Veterinary Drugs Residue Methods


Category Antibacterial substances, including sulfonamides and quinolones
Drug Class Name Cephalosporins
Method Title Screening method for the detection of Ceftiofur in kidney and milk by LCMSMS
Method Date 2010/11/23
Method Type Screening
Scope and Application The method is applicable for screening of residues of Ceftiofur/Desfuroylceftiofur in milk and kidney of food producing mammals
Method Summary All samples are kept at about negative 20 degrees Celsius before preparation Milk extraction and analysis: Thawed samples (2 g plus or minus 0.2 g) are extracted by centrifugation using acetonitrile and water (3 to1, volume by volume). The supernatant volume is reduced by evaporation and then cleaned on a C18 cartridge before eluting the analyte using acetonitrile. Water is then added to the eluate and the mixture further reduced in volume by evaporation. Following overnight storage at 4 degrees Celsius, the residue is treated with dithioeythritol followed by heating and addition of iodoacetamide. This mixture is then acidified with phosphoric acid and cleaned using strong cation exchange (SCX) cartridges with analyte finally eluted using acetonitrile and ammonia solution (9 to 1, volume by volume). This is evaporated to dryness and reconstituted in 0.1 percent formic acid in water and acetonitrile (95 to 5, volume by volume) and pressed through a 0.2 micrometer filter prior to analysis by LC-MSMS in positive ESI mode. A low pH 1.7 micrometer C18 BEH, 100 by 2.1 mm analytical column is used for separation. Kidney extraction and analysis: As in the milk procedure above except that the sample is homogenized after adding dithioerythritol and centrifuged after acidification prior to clean up on SCX cartridge
Applicable Concentration Range Residues of Ceftiofur/Desfurocylceftiofur may be detected in milk and kidney samples at concentrations as low as 0.5µgkg-1 and 3000 µgkg-1, respectively
QC Requirements See SOP
Method Source LGC Limited, UK
Method SOP PDF icon SOP 
Citation See method source