Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/9/2008
Publication Date: 10/19/2008
Citation: Martos, P.A., Lehotay, S.J., Shurmer, B. 2008. Ultra-Trace Analysis of Nine Macrolides, including Tulathromycin A (Draxxin), in Edible Animal Tissues with Mini-Column Liquid Chromatography Tandem Mass Spectrometry. Journal of Agriculture and Food Chemistry. 56(19):8844-8850. Interpretive Summary: The monitoring of antibiotic residues in animal-derived food is important for food safety, enforcement of laws, microbial resistance purposes, risk assessment, international trade, and consumer perceptions. Analytical methods that are faster, easier, and have broader scope are needed to improve the current monitoring programs in regulatory and other laboratories around the world. In this collaboration with Canadian scientists in the Laboratory Services Division at the University of Guelph, a novel and improved method was developed and evaluated for the trace level detection of 9 macrolide antibiotics in beef, poultry, and pork. This method will be used in the Canadian monitoring laboratory, and may be employed in other monitoring labs around the world.
Technical Abstract: Analysis of 9 macrolides is presented, including tulathromycin A (Draxxin), in beef, poultry and pork muscle with a simple multi-residue extraction and analysis method using high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The extraction method involves only the use of acetonitrile with dilution of the extracts for analysis. Separation of the 9 macrolides is performed using a cartridge-style (guard) column: Atlantis guard dC18, 3 um packing, 3.9 mm x 20 mm column. Detection was carried out with two multiple reaction monitoring experiments per macrolide. The method detection limits (MDLs) were based on 3 times standard deviation of 8 repeat spikes at 3.0 ng/g of a mix of the 9 macrolides in the various tissues. The MDLs and retention times for the macrolides were: lincomycin 0.19 ng/g (5.0 min), tulathromycin 0.46 ng/g (5.6 min), spiramycin 0.21 ng/g (6.1 min), pirlimycin 0.10 ng/g (6.0 min), clindamycin 0.16 ng/g (6.2 min), tilmicosin 0.29 ng/g (tR=6.4 min), erythromycin 0.19 ng/g (6.6 min), tylosin 0.10 ng/g (6.7 min) and josamycin 0.09 ng/g (7.0 min). Precision at 25 ng/g (n=4) ranged from 2.3% to 9.4% for the compounds from beef muscle. Of particular interest is the detection of incurred residues of tulathromycin A in edible calf tissue at 0.25 ug/g to 7 ug/g, which is presented here for the first time.