Abstract: Assay apparatus comprising: a moulded cartridge containing a lateral flow test strip which has a label pad containing an enzyme antibody or antigen conjugate having affinity for an analyte; a capture zone having a capture antibody or antigen having affinity for said analyte; a reagent storage blister; a means for removing sample and/or label pad from the lateral flow test strip; a meter in which the cartridge is inserted enabling the control for reagent release from the reagent storage blister and for the sample and/or label pad removal and a means of providing quantitative measurement of said analyte.

Abstract: A sensor format is based on impedance analysis of polymer coatings of electrodes. A detectable signal is produced by the effect of a reactive or catalytic species at or very near the polymer coated electrode. The reactive or catalytic species directly or indirectly effects a reaction with the polymer layers, whereby the polymer layer becomes porous and thus causes a measurable change in electrical properties of the electrode surface.

Abstract: Enzyme electrodes are described which are of reduced sensitivity to alcohol. The electrodes comprise a porous resin-bonded layer of powdered carbon or graphite, onto which the enzyme is immobilized, that layer containing either finely divided platinum oxide, or finely divided platinum the surface of which is provided with a thin oxide film, e.g. by an anodisation process, the finely divided platinum oxide or anodised platinum being uniformly dispersed throughout the resin-bonded carbon or graphite layer and preferably preadsorbed onto the surface of the powdered carbon or graphite prior to bonding. Also disclosed is a method of making such electrodes by a polarization treatment of a preassembled platinized electrode.

Abstract: Enzyme electrodes are disclosed consisting essentially of a uniform homogeneous layer of a finely divided platinum group metal or oxide, preferably preadsorbed onto the surface of an activated carbon or grapite powder, and deposited from suspension upon the surface of an electrically conductive substrate and in admixture with an enzyme and optionally a water soluble or water-dispersible binder. Preferably the enzyme electrodes are produced by coating the substrate with a suspension of the enzyme, the finely divided platinum group metal, and if present the carbon or graphite powder and binder, and drying at a temperature below that at which the enzyme is deactivated.

Abstract: A method is disclosed for the quantitative determination of 1,4-dihydronicotinamide adenisne dinucleotide (NADH) in solution. The method comprises contacting the NADH-containing solution with an activated carbon electrode, maintaining the carbon electrode at a controlled, fixed potential effective to cause oxidation of NADH at the electrode surface, and measuring the current output from the carbon electrode, wherein there is used a noble metal containing preferably a platinized or palladized activated carbon electrode comprising a porous, heterogeneous, resin-bonded layer of activated carbon or graphite particles comprising the finely divided noble metal preadsorbed thereon and bonded together with a natural or synthetic resin binder, preferably a hydrophobic resin such as polytetrafluoroethylene.

Abstract: Enzyme electrodes are disclosed which are capable of responding amperometrically to the catalytic activity of the enzyme in the presence of its respective substrate and comprising the enzyme immobilized or adsorbed onto the surface of an electrically conductive support member which consists of or comprises a porous layer of resin-bonded carbon or graphite particles, said particles having intimately mixed therewith, or deposited or adsorbed onto the surface of the individual particles prior to bonding to form said layer, a finely divided platinum group metal, thereby to form a porous, substrate layer onto which said enzyme is adsorbed or immobilized and comprising a substantially heterogeneous layer of resin-bonded carbon or graphite particles, with said platinum group metal dispersed substantially uniformly throughout said layer.

Abstract: A small, compact plate reader is disclosed for microtitre plates. The reader comprises a totally enclosed housing (19), means e.g. a drawer (2) for receiving and inserting into the housing a microtitre plate (7) which is received into the housing between a light source and a photodetector positioned in vertical alignment above and below the microtitre plate. The light source and detector are mounted on a carriage movable in the housing along each of two orthogonal axes by means of the manual control knobs (10,11) on either side of the housing. The light source and detector are thus positionable with each of the wells of the microtitre plate in turn enabling absorbancy measurements to be made, and visually displayed by a digital display (9).