TRACE ANALYSIS OF ALBENDAZOLE AND ITS SULFOXIDE AND SULFONE METABOLITES IN MILK BY LIQUID-CHROMATOGRAPHY

Analytical methodology for determination of albendazole and its sulpho xide and sulphone metabolites in milk at levels down to 2-5 ng/ml has been developed. Extraction was carried out with ethyl acetate under al kaline conditions, and extracts were analyzed on a silica-based C-18 c olumn in the presence of positively-charged pairing ions. Accuracy dat a showed overall recoveries ranged from 78.4% to 100%, whereas precisi on data, based on within- and between-day variation, suggested overall precision values better than 4.9%. The method was successfully applie d to determine residues in milk of a dairy cow orally given albendazol e.