|Muldoon, Mark - STRATEGIC DIAGNOSTICS INC|
|Desphande, Sudhir - L.J.L. BIOSYSTEMS|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 16, 1999
Publication Date: N/A
Interpretive Summary: Sulfadimethoxine is a drug that is used in the beef, pork and poultry industry to prevent disease due to bacterial infection. Although the drug is useful for keeping animals healthy, drug residues should not be present in meat products that are brought to market. Therefore, various methods of extracting the drug from meat products were investigated to determine which hmethod was most accurate for detecting sulfadimethoxine in tissues. The most rapid test not only detects the original drug, but also fragments of the drug that have attached to proteins in the tissues. When properly analyzed, rapid tests such as the one described here should help producers, as well as government agencies, to screen food for the presence of sulfadimethoxine residues.
Technical Abstract: Several rapid extraction methods were evaluated for use with a monoclonal antibody-based competitive inhibition ELISA (cELISA) to detect sulfadimethoxine (SDM) in chicken liver tissue. These methods included extraction of the samples with (1) aqueous buffer with or without ultrafiltration, (2) acetonitrile/water, (3) methanol/water, or (4) acetone. The aqueous-based extraction methods were compatible with the cELISA. However, of the organic extraction methods, only the acetone liver extract with solvent evaporation prior to analysis was compatible with the cELISA. The cELISA method coupled to aqueous- or acetone-based sample extraction as well as an HPLC method were evaluated for the analysis of chicken liver tissues fortified with SDM at levels from 0.2 ppm to 0.025 ppm. For the analysis of samples obtained from an SDM incurred residue study, HPLC and cELISA analysis of the same extract gave results that was highly correlated (p<0.0001). However, results obtained from the analysis of aqueous extracts by cELISA were much higher than those obtained by the HPLC. This was attributed to the co-extraction of cross-reactive SDM-related residues that were not detected by the HPLC method. The presence of these unregulated residues should be considered during data interpretation when ELISA methods coupled with rapid aqueous extraction of samples are used in SDM residue monitoring programs.