Glucose was detected in fluids using either screen-printed enzyme electrodes or capillary electrophoresis systems. Glucose oxidase (GOD) was immobilized on screen-printed Pt-electrodes by entrapment in a UV-polymerizable paste. The influence of interfering substances (e.g. ascorbic acid) which are oxidized at the same potential used for the determination of the enzymatically produced H2O2 had to be minimized. The effects of some additives were investigated to increase the selectivity,

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... y and stability of the amperometric enzyme electrodes. Addition of Nafion, polyethylene glycol and graphite powder reduced the interferences due to the presence of ascorbic acid. The determination of carbohydrates (especially glucose) using capillary electrophoresis using fused silica capillaries or different types of microchips was investigated. Detection of glucose using soluble enzyme was investigated in glass and PMMA microchips. To reduce enzyme adsorption onto the inner capillary surfaces, the influences of cationic surfactants (CTAB and DDAB) and the anionic surfactant (SDS) were examined. Addition of lower CTAB concentrations to the running buffer containing GOD increased the separation efficiency between glucose and ascorbic acid. Immobilization of GOD in a certain part of the microchip capillary electrophoresis eliminated enzyme adsorption. GOD was immobilized in fused silica and glass microchip by entrapment of the enzyme in an acrylamide gel in the presence of acrylic acid to regenerate electroosmotic flow.