▎ 摘　　要

A novel electrochemical immunosensor was proposed using a poly(amidoamine) dendrimer (PAMAM) modified ionic-liquid-assisted graphene sheets-doped chitosan (GS-CS) hybrid matrix as platform, which were characterized by cyclic voltammograms and scanning electron microscopy. Subsequently, using benzo[a] pyrene (BaP) as a model, a competitive immunoreaction between BaP antigen (BaP-Ag) on the platform and the analyte in testing solution was developed to combine with the limited antibody. Results showed that a rapid and sensitive detection of BaP can be found in the range from 5 nM to 6 mu M with a low detection limit of 3 nM. Such greatly enhanced sensitivity was based on a two-step signal amplification strategy during the fabrication of the sensor platform: firstly, the addition of ionic-liquid-assisted graphene enlarged the surface area of the substrate and improved the conductivity by favoring electron communication between biomolecules and the substrate. Secondly, the introduction of PAMAM can greatly amplify binding sites of the substrate to immobilize antigen. This amplification strategy may offer a simple and inexpensive platform for polycyclic aromatic hydrocarbons (PAHs) fast screening and on-line monitoring.