Study on Electrochemical Immunosenor for Microcystin-LR Based on HDT Self-assembly Au Nanoparticle Modified Electrode

KeyWord:microcystin  gold nanoparticles  self-assembly  immunosensor

Abstract:

      A novel electrochemical immunosensor for microcystin-£¨leucine-arginine£©£¨MCLR£© was developed based on gold electrode modified with Au nanoparticles£¨AuNPs£©.The AuNPs were prepared by the sodium citrate reduction method,and characterized by transmission electron microscopy£¨TEM£© and UV-vis absorption spectroscopy.1£¬6-hexanedithiol£¨HDT£© molecules were modified onto the surface of a gold electrode to form self-assembly monolayer, and then the AuNPs were assembled on the self-assembly monolayer of HDT. The immunosensor was constructed by immobilizing the antibody of microcystin-£¨leucine-arginine£©£¨anti-MCLR£© on the modified electrode. The surface morphology of the AuNPs modified electrode and the electrochemical behaviour of the immunosensor were characterized by scanning probe microscopy£¬cyclic voltammetry and electrochemical impedance spectroscopy£¨EIS£©£¬respectively.MCLR and horseradish peroxidase conjugated MCLR£¨MCLR-HRP£© competitively combined with immobilizing anti-MCLR. The determination of MCLR using the immunosensor was investigated by differential pulse voltammetry£¨DPV£©.Under the optimized conditions£¬a linear range from 0.01¦Ìg/L to 25¦Ìg/L and a detection limit of 0.005¦Ìg/L were obtained by DPV method.The reproducibility£¬stability and selectivity of the immunosensor for MCLR were investigated. The proposed method was applied in the determination of MCLR in real water samples with recoveries of 100%-102%,and the determination results of MCLR were consistent with those obtained by HPLC method.