A simple liquid chromatographic (LC) method is presented for the determination of diminazene (DZ) in raw bovine milk. DZ is extracted from raw milk by chilled aqueous centrifugation and is isolated from milk components on a cyano solid-phase extraction column. DZ is eluted by using
a methanol-ion pairing reagent. A Phenomenex LUNA CN column and an acetonitrile-buffered mobile phase with a counter ion are used for gradient LC. The LC effluent is monitored at a detection wavelength of 372 nm by using a deuterium lamp. Under the parameters described, the retention time
of DZ is 8–10 min with a peak area response of 6.5 mAU/ng. The method demonstrated excellent precision over all levels tested (25–400 ppb) with an overall average recovery of 90.4 ± 14.5%. The method is applicable to the monitoring of milk for DZ residues at the 25 ppb level
with a limit of quantitation of 10 ppb.
Document Type: Research Article
U.S. Food and Drug Administration, Animal Drugs Research Center, Denver Federal Center, PO Box 25087, Denver, CO 80225-0087
Publication date: September 1, 2003
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The Journal of AOAC INTERNATIONAL publishes refereed papers and reviews in the fields of chemical, biological and toxicological analytical chemistry for the purpose of showcasing the most precise, accurate and sensitive methods for analysis of foods, food additives, supplements and contaminants, cosmetics, drugs, toxins, hazardous substances, pesticides, feeds, fertilizers and the environment available at that point in time. The scope of the Journal includes unpublished original research describing new analytical methods, techniques and applications; improved approaches to sampling, both in the field and the laboratory; better methods of preparing samples for analysis; collaborative studies substantiating the performance of a given method; statistical techniques for evaluating data. The Journal will also publish other articles of general interest to its audience, e.g., technical communications; cautionary notes; comments on techniques, apparatus, and reagents.