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The objective of this project is to develop and validate a High Performance Liquid Chromatography (HPLC) method for the determination of sulfonamide residues in animal
tissues.
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A method has been developed for the detection and quantitation of eight sulfonamide residues in swine muscle and liver. Sulfamonomethoxine or sulfamethoxypyridazine is added to the tissue as an internal standard to correct for variations in recovery. Sample clean-up begins with homogenization with sodium sulfate and ethyl acetate, followed by centrifugation and removal of the solvent by evaporation. The residue is redissolved in an ethyl acetate-hexane solution, and loaded on to cation exchange solid phase extraction columns. The sulfonamides are eluted with a buffer-acetonitrile solution. An aliquot is derivatized with fluorescamine and 25µL injected on to the HPLC. Separation is by reversed-phase HPLC with a gradient mobile phase consisting of acetate buffer and acetonitrile. The calibration curves for the sulfonamides cover the range of 0.05 ppm to 0.2 ppm (r 0.995). Limit of detection is 0.005 ppm and limit of quantitation is 0.015 ppm or better. Repeatability at 0.1 ppm ranges from 6.6% to 13.3%.
Expected Impact of Project Outcomes on Food Safety in Ontario:
This method offers several advantages. It uses no halogenated solvents, which are toxic and expensive to dispose of. It removes the need to maintain an aging and obsolete scanning densitometer that has limited application. The Ontario food system will benefit from the wider range of sulfonamide residues capable of being detected and quantified in the meat of food animals. It is anticipated that the method will be readily adaptable to other matrices, such as meat-and-bone meal, and feed.
<P> For more information, please visit the <a href="http://www.omafra.gov.on.ca/english/research/foodsafety/index.html" target="_blank">Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA) Food Safety Research Program</a>.