Aminoglycoside Antibiotics in Feed: Apramycin and Neomycin

Aminoglycoside antibiotics are among those commonly used in animal feeds to manage intestinal microorganisms. The beneficial effects include improved growth and generally healthier animal populations. Use of antibiotics creates a demand for analytical procedures to verify concentrations in pre-mixes and feeds and in some instances for residue analysis in animal products.

Figure 1

This note describes a simple, robust analytical method for the family of Aminoglycoside antibiotics in feeds and animal products. The sample is homogenized with a generic extraction solution and the crude, soluble portion is directly injected into an HPLC ion-exchange column. The column effluent is then mixed with an OPA/Thiofluor™ reagent which forms highly fluorescent derivatives with the primary amine moieties of the antibiotics.

Figure 2

Extraction procedure:

Take one part feed: 10 parts (w/v) Pickering Extraction solution catalog No.1700-1118 and homogenize for 5 min. Centrifuge for 10 min. Three layers will form: the pellet, a supernatant emulsion, and a soft layer of floating fat. Carefully lift the floating fatty layer with a spatula and discard. Transfer the emulsion to a sealable vial. Coagulate the emulsion by placing the vial in a boiling water bath for 15 min. Centrifuge for 10 min. The clear supernatant is filtered (0.45μm nylon) and placed in an autosampler vial.

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