In this master thesis, a novel test setup to characterize the oxygen increase of liquids in blood analyzers was implemented. For this purpose an optochemical sensor, embedded in a cell made of steel, was used. The measurement principle was tested with seven selected tube-materials. With the developed practice-relevant test sequences, it was possible to give information about the oxygen exchange properties of the materials. One of the selected materials, a copolymer, showed by far the best practice-relevant properties (lowest oxygen increase) and is performing even better than steel pipes. Another conclusion is that a thermoplastic elastomer can replace a more expensive rubber in an analyzer, as it shows similar oxygen exchange behaviour. Furthermore it was possible to give information about the oxygen exchange behaviour of a multilayer, two thermoplastics and a further selected thermoplastic elastomer. The permeation coefficient was found to be suitable for the pre-selection of materials with providing an idea of the magnitude of the oxygen increase within the operational sequences of a blood analysis device. Because of the significant influence of the sorption on the oxygen exchange behaviour there is a need for practice-relevant tests when comparing two materials directly. An important material-independent pump-effect, which contributes to an increase of the oxygen, was identified. At the air/liquid phase boundary, a diffusion-induced O2-uptake occurs, that is transported inside the liquid due to laminar flow conditions.