Study On The Visual Immunoassay For Rapid Detection Of Gentamicin

In this paper, the visual and rapid immunoassay methods were developed for the detection of Gentamycin (GEN).The GEN residues in some animal derived food were detected by immunochromatographic strip and immunoaffinity test column, respectively.Colloidal gold was prepared for labeling the polyclonal antibody of GEN. GEN was conjugated to the ovalbumin (OVA) as the coating antigen. Gold chloride was reduced with the sodium citrate to make20nm colloidal gold. The optimal pH for the preparation of the colloidal gold labeled-polyclonal antibody (pAb) conjugate was8.5and the optimal amount of the antibody was25μg. The colloidal gold-labeled antibody was successfully prepared under the optimal conditions. The GEN-OVA and goat anti-rabbit IgG were dispensed on test line and control line respectively and the gold-labeled antibody was dry coated on the glass cellulose membrance to assemble the immunochromatographic stripColloidal gold immunochromatographic assay for the detection of GEN was convenient and rapid, the detection result can be obtained within10min and the limit of detection (LOD) was25μg/L. There were no cross reaction with the similar veterinary drugs and the other commonly used ones which shows high specificity. Milk, beef, pork, liver, kidney, chicken, fish, eggs were chosen as the samples. Spiked samples with three different concentrations of GEN and all samples didn’t need treat with organic solvent. The LOD of milk is100μg/L, beef and pork’s were50μg/kg, the others’ were100μg/kg. Those were all lower than the maximum residue limit. The results obtained by test strip were coherence with the results obtained by ELISA. The test strip could be reserved for more than2monthsunder the sealed and dry condition at4℃. The developed test strip assay were rapid, accurate and don’t need any device instrument which could be widely used to screen the GEN residues in animal foods on-site.The developed gel-based assay allows for the first time on-site screening for the qualitative determination of GEN in animal foods, milk, beef, pork and chicken were10times diluted by PBS. The LODs is100μg/L (μg/kg). For analytical method of the is simple and rapid, it provides new idea and approach to the novel, visual and rapid determination.