In this study, DNA was first fabricated on a glassy carbon electrode by UV-irradiation. Through this process, water-soluble DNA was converted into insoluble materials, and a stable DNA film formed on the electrode. Ethidium bromide (EtBr), a typical model substance for harmful chemicals having planer structure, was used as an electroactive intercalator. This allowed our group to investigate the electrochemical and accumulative behaviors of the intercalator in UV-irradiated DNA film on the electrode. The UV-irradiated, DNA film-modified electrode (UV-DNA-FE) made it possible to accumulate electroactive EtBr on the electrode and detect it after accumulation. The modified electrode was used to detect dibenzofuran (DBF) as an environmental pollutant. The measurements were successfully obtained by focusing on the variation of the electrode response of EtBr, based on the competitive reaction between EtBr and DBF for the intercalating sites of DNA. The results indicated the possibility of using UV-DNA film as a sensing mechanism. (c) 2007 Elsevier B.V. All rights reserved.