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A Novel Green Chemistry Method for Nonaqueous Extraction and High-Performance Liquid Chromatography Detection of First-, Second-, and Third-Generation Tetracyclines, 4-Epitetracycline, and Tylosin in Animal Feeds
- Granados-Chinchilla, Fabio, Sánchez, Jorge, García, Fernando, Rodríguez, César
- Journal of agricultural and food chemistry 2012 v.60 no.29 pp. 7121-7128
- animal nutrition, chlortetracycline, correlation, doxycycline, feeds, green chemistry, high performance liquid chromatography, minocycline, oxytetracycline, solid phase extraction, tetracycline, tylosin, Costa Rica
- Although tetracyclines and macrolides are common additives for animal nutrition, methods for their simultaneous determination in animal feeds are nonexistent. By coupling an organic extraction and solid-phase extraction cleanup to a high-performance liquid chromatography separation and a nonaqueous postcolumn derivatization, we succeeded in detecting from 0.2 to 24.0 μg kg–¹ of tetracycline, oxytetracycline, chlortetracycline, doxycycline, tigecycline, and 4-epitetracycline in this complex and heterogeneous matrix. Minocycline and tylosin could also be detected with our procedure, but using UV spectrophotometry (1.5 ≤ LOD ≤ 1.9 mg kg–¹). Linear responses with correlation coefficients between 0.996 and 0.999 were obtained for all analytes in the 0.5–10 mg kg–¹ concentration range. Average recoveries between 59 and 97% and between 98 and 102% were obtained for the tetracyclines and tylosin, respectively. Replicate standard deviations were typically below 5%. When this method was applied to 20 feeds marketed in Costa Rica, we detected labeling inconsistencies, banned mixtures of tetracyclines, and tetracycline concentrations that contravene international regulation.