ANALYTICAL METHODS TO DETERMINE RESIDUAL CYPERMETHRIN AND ITS MAJOR ACID METABOLITES IN BOVINE-MILK AND TISSUES

Several analytical methods were developed to determine cypermethrin an d its acid metabolite residues in bovine milk, cream, kidney, liver, m uscle, and fat samples. These methods used solvent extraction or acid reflux, liquid-liquid and/or solid phase extraction, with or without c hemical derivatization, and quantitation by gas chromatograph with ele ctron capture or mass selective detector. The LOQ and LOD for milk wer e set at 10 and 2 ppb, respectively. The average method recoveries for cypermethrin, cis-DCVA, trans-DCVA, and m-PBA in cow milk were 81% (n =39), 96% (n=22), 99% (n=22), and 106% (n=22), respectively. For bovin e tissues and cream samples, the LOQ and LOD were 50 and 10 ppb, respe ctively. The overall average method recoveries for cypermethrin, cis-D CVA, trans-DCVA, and m-PBA in cream and tissue samples were 92% (n=27) , 97% (n=25), 103% (n=25), and 98% (n=25), respectively. Satisfactory recoveries were also obtained with higher fortification levels for mil k and fat samples.