In this work, we developed an immunosensor for electrochemical detection of penicillin G at trace level. The biosensor was fabricated by immobilizing anti-penicillin G in a supported bilayer lipid membrane (s-BLM) modified with gold nanoparticles, and the modified electrodes were characterized by the scanning electron microscope (SEM), cyclic voltammetry and electrochemical impedance spectroscopy. The biosensor was able to detect penicillin G with a linear correlation ranging from 3.34×10(-3)ng/L to 3.34×10(3)ng/L and a detection limit of 2.7×10(-4)ng/L, much lower than the maximum residue limit (MRL) of penicillin G in milk (4ppb, equal to 4×10(3)ng/L) set out by the European Union. The mean coefficient variation (CV) of the intra-assays and the inter-assays were 5.4% and 7.7%, respectively. In addition, the concentration of penicillin G in milk samples determined by this biosensor was in good agreement with that determined by high performance liquid chromatography (HPLC) assay.
Keywords: Biosensor; Gold nanoparticles; Penicillin G; Supported bilayer lipid membrane.
Copyright © 2015 Elsevier B.V. All rights reserved.