Abstract:An amperometric immunosensor with enhanced sensitivity was successfully developed by co-immobilization of multi-walled carbon nanotubes (MWCNTs), Chitosan (CS), and HRP labled penicillin polyclonal antibody (HRP-Ab*) on glassy carbon electrode using a layer-by-layer assembly technique. HRP can catalyze the reduction of H2O2 to promote the oxidation of hydroquinone, causing the changes in impedance, thus realizing the quantitative detection of penicillin according to the current changes. The milk samples were pretreated by salting out to remove the protein and fat. And the effects of pH of buffer solution，immune temperature and time were investigated. Under optimized conditions, the current response of the sensor showed a good linear relationship with the concentration of penicillin in 0.05~5.00 μg/L, with the correlation coefficient of 0.9853 and the detection limit of 1.05 μg/L. This method was fast, simple and reliable, with high sensitivity, specificity compared to enzyme-linked immunosorbent assay (ELISA). It was proved to be suitable for detection of penicillin residues in milk samples .
