The scientific goal of the project is to design and produce a reagentless prototype lab-on-a-polymerchip oxygen sensor based on the Clark principle. Experience with Clark principle based oxygen sensors exists to some extent already, but since the goal of this project is to develop a miniaturized, fully integrated sensor in a basic polymer design a host of novel scientific aspects will present themselves in the course of the project The overall efficiency of the sensor, its response function, and its long term behavior have to assessed using potentiometric methods. These are essential for improving and optimizing the final sensor and for continous monitoring of the influence of the process parameters. Membranes will play a key role in the sensor design. Novel semi permeable membranes, e.g. siloprene rubber and cyclic olefine, will be required to separate the delicate microelectrode array from the liquid which may otherwise contaminate the system. In order to understand membrane diffusion techniques for measuring diffusitivity and permeability have to be established, i.e. temporal current response to oxygen injection. Sensor miniaturization and incorporation with a laser machined micro fluidic device into a µTAS system also poses scientific challenges. Since the substrate will be a polymer and the electrodes metallic adhesive properties must be investigated. Also flow-cells for oxygen have to be developed. Project task I will focus on the electrochemical design including the microelectrode array and task II will locus Polymer materials technology and laser machining of the micro fluidic part of the system.