A simple conducting polymer-based biosensor for the detection of atrazine

In this paper, we present preliminary results for the preparation and application of a biosensor intended to detect photosynthetic inhibiting herbicides such as atrazine. Our approach is based on the preparation of a glassy carbon electrodes operating at open-circuit and serving for the immobilization of the enzyme polyphenol oxidase (PPO) during the anodic electropolymerization of polypyrrole (PPy). The enzyme is trapped at the electrode surface during the electrochemical synthesis process. A biological reactor can then be realized. Once the biological reactor (the film at the electrode surface) is prepared, another electrode is used as a redox product detector of PPO catalytic activity. The concentration of atrazine in aqueous solution can be determined, thanks to its inhibitory power toward the catalytic activity of PPO represented by the produced quinone concentration. A long electrode lifetime is achieved, thanks to the well-known high mechanical stability of the conducting polymer PPy and to the absence of polarization of the first electrode (open-circuit conditions). The interesting analytical performances and simplicity of fabrication of our biosensor suggests its possible application for photosynthetic inhibiting herbicide monitoring.