Determination of sulfamethazine in swine serum with one-step ELISA test kit

Sulfamethazine is a suspected carcinogen. It is widely used as feed additive for swine rations. An effective way of reducing this high incidence of sulfamethazine violations in swine would be to implement a nationwide slaughterhouse surveillance program for the drug. The traditional method for the detection of sulfamethazine spends too much time. A rapid screening test of sulfamethazine residue in swine serum was made by the use of the sulfamethazine one-stop Enzyme-Linked Immunosorbent Assay (ELISA) Kit. The time for sample preparation and reaction in microwells and read in ultrascan meter was about 30 minutes. The detection limit of sulfamethazine was 0.001 ppm. The mean recoveries of added sulfamethazine from serum at levels 0.04, 0.2, and 0.42 μg/ml were 99.8% (coefficient of variation, CV = 2.92%). Among 11 sulfonamide analogus: sulfamethazine, sulfamerazine, sulfadimethoxine, sulfamonomethoxine, sulfathiazole, sulfamethoxypyridazine, sulfaquinoxaline, sulfamethoxazole, sulfapyridine, sulfisoxazole and sulfadiazine with 4 different concentrations: 0.001, 0.01, 0.1 and 1.0 μg/ml had cross reaction to antibodies in the ELISA Kit. The relative reactivity of sulfamethazine, sulfamerazine, sulfisoxazole and sulfapyridine were 100, 10.0, 3.4 and 2.0%, respectively. The concentration of sulfonamide below 0.1 μg/ml, the cross reaction was neglected. This ELISA kit may be used as a rapid screening test for sulfamethazine residue in swine serum.