Urine hydrogen peroxide concentration

Glucose measurements in urine and fermentation samples by means of GOD electrodes based on hydrogen peroxide detection usually suffer from interferences by anodically ox-idizable compounds. These can be oxidized in the measuring solution by reaction with hexa-cyanoferrate(III). However, the hexacyanoferrate(lI) ion formed is also oxidizable at an electrode potential of +600 mV. In order to prevent the hexacyanoferrate(II) from reaching the electrode, laccase has been co-immobilized with GOD in the sensor membrane [352]. Thus, the mediator is reoxidized in a laccase-catalyzed reaction with consumption of oxygen. The system is capable of shielding the electrode from ascorbic acid at concentrations up to 2 mmol/L. 

Biosensors have recently become an area of great Interest, especially in clinical chemistry. These sensors can be used to determine analyte concentrations in clinical samples, such as blood serum and urine. Electrochemical biosensors are constructed by incorporating a biochemical system, such as an enzyme, with an electrode. Amperometrlc biosensors often use oxidase enzymes, such as glucose oxidase, as the sensing enzyme. A major product of these types of enzymatic reactions is hydrogen peroxide, which can be oxidized at eun electrode surface. The current produced by the oxidation of hydrogen peroxide is directly proportional to the enzymatic substrate concentration. 

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