Development of a monoclonal antibody-based ELISA for detection of sulfamethazine and N4-acetyl sulfamethazine in chicken breast muscle tissue

An anti-sulfamethazine monoclonal antibody was developed in a BALB/c mouse immunized with sulfamethazine (SM2)-human serum albumin (HSA). Using this monoclonal antibody, an indirect competitive enzyme-linked immunosorbent assay (cELISA) was developed to detect SM2 and its metabolites in chicken breast muscle tissue. The 50% inhibition value (IC50) was 9.3 ng/mL. When SM2 was spiked at levels of 20 to 200 ng/g, recoveries ranged from 81.3% to 104.2% with coefficients of variation (CVs) of 4.3% to 19.3%. The metabolite N-4-acetyl SM2 was also evaluated by the same assay. When it was fortified at levels of 20 to 200 ng/g, recoveries ranged from 80.4% to 100.8% with CVs of 3.0%, to 14.2%. The results were confirmed with analysis by high-performance liquid chromatography (HPLC). In an actual residue study, the results obtained by cELISA did not correlate well with those obtained by HPLC (P < 0.05). This might be due to the coextraction of cross-reactive SM2-related residues that were not quantified by the HPLC method. The study indicated that the presence of residues should be anticipated when considering the maximum residue limit of SM2 residue.