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.
Thomas
M H
MH
Food and Drug Administration, Division of Veterinary Medical Research, Beltsville, MD 20705.
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