Gold immunochromatographic sensor for the rapid detection of twenty-six sulfonamides in foods

A gold immunochromatographic sensor (GICS) was developed for the rapid detection of 26 sulfonamides in honey samples. The sensor was based on a group-specific monoclonal antibody (mAb) that can recognize all 26 sulfonamides. Three haptens (hapten 1 with a thiazole ring, hapten 2 with a benzene ring, and hapten 3 with a straight carbon chain) were used for antigen preparation. With hybridoma technology, a group-specific mAb was screened with a 50% maximal inhibitory concentration (IC₅₀) against sulfathizole (STZ) and the other 25 analogues ranging from 0.08 to 90.18 ng/mL. Mono-dispersed gold nanoparticles were conjugated with the mAb to develop the lateral immunochromatographic strip. A labeled antibody concentration of 0.1 μg/mL and a coating antigen concentration of 0.2 μg/mL in the test line were chosen for strip preparation. Under optimized conditions, the visual limits of detection (vLOD) for the concentrations of STZ, sulfamethoxazole, sulfamethizole, sulfadiazine, sulfamerazine, sulfadimethoxine, sulfamonomethoxine, sulfameter, sulfamethoxypyridazine, and sulfachloropyridazine were 5, 0.25, 0.25, 10, 5, 10, 25, 2.5, 5, 0.25, and 10 μg/kg, respectively. Scanner analysis in honey samples revealed good performance for detection of the 26 sulfonamides. Commercial honey samples were tested with the sensor and positive results were confirmed with high-performance liquid chromatography. The proposed strip sensor provides a convenient method for the rapid and reliable determination of sulfonamides pollutants in honey samples.