Quadruplex gold immunochromatogaraphic assay for four families of antibiotic residues in milk.

In this study, we developed a quadruplex gold immunochromatogaraphic assay (GICA) for the simultaneous determination of four families of antibiotics including β-lactams, tetracyclines, streptomycin and chloramphenicol in milk. For qualitative analysis, the visual cut-off values were measured to be 2-100 ng/mL, 16-32 ng/mL, 50 ng/mL and 2.4 ng/mL for β-lactams, tetracyclines, streptomycin and chloramphenicol, respectively. For quantitative analysis, the detection ranges were 0.13-1 ng/mL for penicillin G, 0.13-8 ng/mL for tetracycline, 0.78-25 ng/mL for streptomycin, 0.019-1.2 ng/mL for chloramphenicol in milk respectively, with linear correlation coefficients higher than 0.97. The spiked experiment indicated that the mean recoveries ranged from 84.5% to 107.6% with coefficient of variations less than 16.2%, and real sample analysis revealed that the GICA can produce consistent results with instrumental analysis. These results demonstrated that this novel immunoassay is a promising approach for rapidly screening common antibiotic residues in milk.