Abstract: A biosensor for the detection and determination of the concentration of toxins by use of enzyme inhibition. Inhibition biosensors are affected by non-specific denaturation and substrate utilization which both result in a limited operational lifetime. These problems are mitigated by providing in an environment an enzyme which is oxidized by hydrogen peroxide the oxidized enzyme being reduced by an electron transfer agent, such as ferrocene, which is itself oxidized in the process. The electron transfer agent is capable of regeneration back to the reduced state and the extend of electron transfer regeneration gives a measure of enzyme inhibition by toxin. Electro-chemical technique allows for the generation of hydrogen peroxide from oxygen in aqueous media and the reduction of oxidized electron transfer agent. Immobilization of the enzyme to an electrode increases efficiency while potentially reducing denaturation. The biosensor can be used for the environmental determination of toxins like cyanide.

Abstract: The present invention is concerned with a chemical sensor, more specifically with a chemical sensor which is capable of detecting the presence of, measuring a quantity of or monitoring the level of N-acetyl primary aromatic amines, such as paracetamol, in whole blood.The specification relates to a method of assay of the type in which an electrode poised at a suitable potential is contacted with a system comprising;(a) a sample suspected to contain paracetamol or a derivative thereof, and(b) an enzyme capable of catalyzing the hydrolysis of an N-acylated primary aromatic amine or a derivative thereof, and,wherein the current flowing in the electrode is a measure of the quantity of hydrolysis products formed and thereby of the concentration of N-acylated primary aromatic amine or derivatives thereof in the sample.