A novel impedimetric biosensor for detection of a wide variety of compounds has been designed and developed. The biosensor is based on a non-isolated surface and non-labelled immunoreactives. The chemical recognition layer was deposited on the surface of the inter digitated μ-electrodes (IDμE's) area (fingers and inter-digits space). Typically, the biosensors and their functionalization are characterized by chemical affinity methods, and impedance spectroscopy in frequencies ranges of 0.1 mHz to 100 kHz. This work describes the biosensor characterization to 1 MHz and the biosensor response without buffer solution to the pesticide atrazine. This work presents an alternative detection method using this biosensor, which was designed to be characterized in the range of frequencies usual in impedance spectroscopy. This detection method allows a simple measure, an easy interpretation and from the electronic point of view is very suitable.