Pg. Schermerhorn et al., DETERMINATION OF SPECTINOMYCIN RESIDUES IN BOVINE-MILK USING LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION, Journal of agricultural and food chemistry, 43(8), 1995, pp. 2122-2125
A method capable of quantifying spectinomycin in raw bovine milk was d
eveloped and validated for 100-400 ng/mL. In this procedure the milk i
s centrifuged at -4 degrees C and the top fat layer removed. The defat
ted milk is deproteinated by precipitation with 30% trichloroacetic ac
id and centrifugation. The supernatant is washed sequentially with dic
hloromethane, hexane, and ethyl acetate. An aliquot of the separated a
queous layer is prepared for HPLC analysis by mixing with 1-decanesulf
onic acid and filtering. The analyte is separated from the matrix comp
onents using an ion-pair mobile phase and a reversed-phase column; the
analyte is quantified with an electrochemical detector. Mean recoveri
es are 80% for milk fortified at 100 ng/mL, 76% for milk fortified at
200 ng/mL, and 77% for milk fortified at 400 ng/mL. The intralaborator
y coefficients of variations are 18%, 6%, and 9%, respectively.