title: Single-laboratory validation for the quantification of neomycin B and neomycin C in animal feeds by liquid chromatography fluorescence detection with post-column derivatization.
abstract: A method using ion-exchange liquid chromatographic (LC) separation, post-column derivatization, and fluorescence detection to quantify neomycin B and neomycin C in animal feeds has been developed and validated. Improved methodology is required to achieve positive identification of antibiotics present and to more accurately determine the amount of antibiotics in feeds. The method sample range covers additive levels found in type A, B, and C medicated feed products (50-0.005% wt/wt neomycin base). The linear range for the method covers 50-150% of expected sample concentrations. Average recovery from type A and B feeds, n = 9, was 100.4% neomycin with %RSD = 2.28. Average recovery from type C feeds and milk replacers, n = 9, was 97.5% neomycin with %RSD = 4.36. There were no interferences from soybean meal and milk replacer matrix components, oxytetracycline, or other aminoglycosides, with the exception of one gentamicin isomer, which co-elutes with neomycin B. However, neomycin and gentamicin are not a legal feed combination, and the presence of gentamicin can easily be discerned by the appearance of the 3 gentamicin homologs that do not interfere. Comparison of the proposed LC method to the microbiological method shows that the LC method provides comparable recoveries of neomycin from feed products throughout the range of concentrations found commercially.
authors.affiliation: South Dakota State University, Chemistry and Biochemistry, SSH 121 Box 2202, Brookings, SD 57006, USA. julee.driver@sdstate.edu
authors.forename: Julee Lynn
authors.initials: JL
authors.lastname: Driver
authors.forename: Nancy
authors.initials: N
authors.lastname: Thiex
authors.forename: Douglas
authors.initials: D
authors.lastname: Raynie
authors.forename: Maria
authors.initials: M
authors.lastname: Ofitserova
authors.forename: Michael
authors.initials: M
authors.lastname: Pickering
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000900:Anti-Bacterial Agents / Q000032:analysis; D002853:Chromatography, Liquid / Q000379:methods; D005601:Framycetin / Q000031:analogs & derivatives* / Q000032:analysis*; D016018:Least-Squares Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D000900:Anti-Bacterial Agents; D005601:Framycetin; C031332:neomycin C