Simultaneous determination of oxytetracycline, tetracycline, and chlortetracycline in milk by liquid chromatography.
A simple, rapid procedure is described for the simultaneous quantification of 3 tetracycline drugs in bovine milk. Samples are prepared by dilution with an EDTA/phosphate buffer solution and filtration through a molecular weight cutoff filter. Analytes are concentrated on-column using a reverse-phase gradient elution system of oxalic acid, acetonitrile, and methanol. The limits of quantitation are approximately 15-50 ng/mL and the limits of detection are 10-20 ng/mL, depending on the compound. For oxytetracycline, over the range 50-1200 ng/mL, the average recovery and intralaboratory coefficient of variation were 97% and 4.1%, respectively. Over the same range, these parameters were, respectively, 97% and 5.0% for tetracycline, and 89% and 6.4% for chlortetracycline. The applicability of this procedure is demonstrated by separation and detection of incurred tetracycline residues in milk from treated animals.
Food and Drug Administration, Division of Veterinary Medical Research, Beltsville, MD 20705.
M H
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Thomas
D000818:Animals; D002417:Cattle; D002751:Chlortetracycline / Q000032:analysis / Q000493:pharmacokinetics; D002853:Chromatography, Liquid; D005260:Female; D008892:Milk / Q000032:analysis* / Q000378:metabolism; D008970:Molecular Weight; D010118:Oxytetracycline / Q000032:analysis / Q000493:pharmacokinetics; D013056:Spectrophotometry, Ultraviolet; D013754:Tetracyclines / Q000032:analysis* / Q000493:pharmacokinetics
D013754:Tetracyclines; D002751:Chlortetracycline; D010118:Oxytetracycline