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Virginiamycin is an antibiotic in our country is allowing the use of the drug feed additives. Virginiamycin in animal feed was added to promote animal growth, improve feed efficiency significantly. For cross-resistance considerations, the European Union has banned the use of virginiamycin in animal feed since 1999. Therefore, the study to establish a method to determin the contents of virginiamycin in feed have a very important practical significance for the monitoring of the reasonable and lawful use of virginiamycin, standardize production enterprises and farmers feed the drug feed additives.This study established a HPLC method to determin the contents of virginiamycin in feed. The sample was extracted with 20mL ethylacetate. Centrifugation, take 10mL upper clear liquid with 5g anhydrous sodium sulfate and lOmL hexane mixture. Centrifugation, the supernatant was purificated by Sep-Pak silica gel and OASIS HLB cartridges. Wash the cartridges with 5mL methanol, and the elution solution was dried at 50℃by nitrogen,then the residues were also dissolved with 0.5～5mL mobile phase, filtered with 0.45μm membranes after mixing, and then measured with external standard on machine.HPLC detection limit was 0.5mg/kg, quantitative limit was 2mg/kg,standard samples ranged from 2μg/mL to 500μg/mL had a good linear relationship,correlation coefficient R2> 0.999. When the addition concentration was 2mg/kg,10mg/kg and 50mg/kg in compound feed,the average recovery was 84.77%～95.75%, RSD was2.35%～6.41% within group,and 4.01%～4.32% between group. When the addition concentration was 5mg/kg,100mg/kg and 500mg/kg in concentrated feed, the average recovery was 83.82%～96.34%,RSD was 2.38%～7.43% within group,and 3.62%～4.98% between group. When the addition concentration was 25mg/kg,2500mg/kg and 1000mg/kg in premix feed,the average recovery was 88.01%～97.7%,RSD was 2.31%～5.48% within group,and 2.67%～3.64% between group.
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