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

Amethod 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 (500.005 wt/wt neomycin base). The linear range for the method covers 50150 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.

Single pot in situ aqueous derivatization and subsequent determination of streptomycin and dihydrostreptomycin residues in honey by means of mass spectrometry

“…Alternatively, in order to avoid the use of ion-pair reagents and HILIC, researchers proposed derivatization-centric processes to retain and separate AMGs on the reversed-phase column. Pre-column and post-column derivatization approaches were applied to this extent ( Chang & Yu, 2011;Driver et al, 2009;Pang et al, 2004). Nevertheless, it has seemed that the addition of a derivatization step into the sample pretreatment workflow leads to elongated total analysis time.…”

Control of Antimicrobials in Feed Using Liquid Chromatography–Tandem Mass Spectrometry: Assessment of Cross-Contamination Rates at the Farm Level

“…To assess the on-farm cross-contamination rate of feed in France, the first step is to develop a sufficiently sensitive and specific multiresidue method for the quantification of antimicrobials in different types of feed at cross-contamination levels of concentration. Many methods have been developed for the analysis of a specific antimicrobial or a specific family of antimicrobials in feed, − but only a few methods have been published in regard to multiresidue quantification of antimicrobials in feed. The method developed by Cháfer–Pericás et al is for fish feed only, but the methods described by Robert et al and Da Silva et al have wider applications.…”