[O2 sensitive L-lactate biosensors with enzyme membranes based on L-lactate-2-monooxygenase and L-lactate-oxidase with electroanalytic comparison].

O2-sensitive biosensors using oxidase membranes have acquired considerable electro-analytical importance. Since some of these O2-converting enzymes also produce H2O2, the use of additive reagents for the O2-free breakdown of the H2O2 in the second reaction has repeatedly been reported. In contrast to L-lactate oxidase, L-lactate-2-monooxygenase converts its substrate without producing H2O2.

[Long-functioning beta-D-glucose and L-lactate biosensors for continuous flow-through measurements for "fouling"-resistant and selectivity-optimized serum- and hemoanalysis].

Bioelectrochemical membrane-electrodes for O2-sensitive enzymatic flow-through analysis of beta-D-glucose and L-lactate are described. The enzyme-membranes of the biosensors consist of glucose-oxidase or lactate-oxidase molecules cross-linked with glutardialdehyde between two dialysis membranes. The accuracy of the biosensors is demonstrated by electroanalysis of diluted control serum and compared with redox-mediator-free H2O2 detection and photometric methods.

[Urea sensor for the continuous ammonium-selective enzymatic process control of the artificial kidney].

Presented is a flow-through method for continuous ammonium-selective enzymatic monitoring of the artificial kidney by means of a bioelectrochemical urea electrode. The urea is converted in an enzyme membrane by covalently bound urease and the ammonium ions are detected by a Nonactin-PVC-membrane. In addition to detailed data from the oxygen-independent solid-state contact sensor, curves are obtained on-line from the patient during the haemodialysis session.