Abstract: An apparatus and method for performing enzyme-linked immunological sandwich assays (ELISA) by affinity chromatography. Formation of the antibody-antigen-conjugate complex, and the development of a chromatophore indicator take place in a semi-automated, walk-away, fashion. The immunoassay apparatus comprises a chromatography tank, which further comprises a reaction compartment and a plurality of liquid solvent reservoirs, with a first-liquid reservoir being configured higher than a second-liquid reservoir. The apparatus allows automatic sequential and discrete movement of wash solution, followed by a color development solution, with unbound conjugate being substantially washed away from the immunological sandwich complex before the color development solution automatically comes into contact with the immunological complex.

Abstract: A fluid receptacle is provided with a retainer on the inner surface thereof for confining at least the reactive portion of a coated insert matrix within the receptacle during inversion thereof. The insert has a configuration permitting fluid to be poured into the receptacle and decanted from the receptacle by inversion of the receptacle with the reactive portion of the insert confined therein. The various decanting, washing and measuring operations involved in an assay may therefore be performed while the insert remains confined within the original receptacle, eliminating the need for additional receptacles and for manual assembly or disassembly operations during the assay.

Abstract: A method for performing multiple, simultaneous in vitro diagnostic tests is provided. The method utilizes a solid phase device comprising a receptacle and an insert. The receptacle has one or more fixed components immobilized on its inner surface. The insert has one or more fixed components--different from those immobilized on the receptacle--immobilized on its surface which is in contact with a fluid sample when inserted therein. The test is performed by placing a fluid sample, having two or more mobile components reactive with the fixed components, into the receptacle and in contact with the insert for a period of time and measuring the changes which are a function of the concentration of the mobile components.

Abstract: A method for measuring the activity of angiotensin converting enzyme is disclosed. In this assay, benzoylphenylalanylalanyproline or a radioisotope labelled form thereof is used as the substrate for the angiotensin converting enzyme.

Abstract: An improved method for performing an in vitro diagnostic test is provided. The method utilizes a solid phase device having a fixed component immobilized on its surface which is in contact with a fluid sample when inserted therein. The improvement resides in utilizing a receptacle, into which the device is inserted, having the same fixed component immobilized on the inner surface of the receptacle. The test is performed by placing a fluid sample, having a mobile component reactive with the fixed component, into the receptacle and in contact with the insert for a period of time and measuring a change which is a function of the concentration of the mobile component.

Abstract: A method and apparatus for conducting chemical reactions at a liquid-solid interface wherein a reaction component is fixed on the surface of a solid phase immersed in a liquid phase containing a freely diffusing, mobile reaction component. The apparatus comprises a substantially smooth-surfaced matrix of appropriate geometrical configuration designed to provide a large surface to volume ratio, a short transfer distance from the mobile component to the fixed component distributed on the solid phase surface and to drain freely upon removal from the reaction liquid.

Abstract: A method and solid phase matrix is disclosed which has special utility for use in conjunction with automatic pipetting apparatus for conducting reactions at a liquid-solid interface. A reaction component is fixed on the surface of the solid phase matrix which is wetted by a liquid phase containing a freely diffusing, mobile component. The matrix is comprised of a support surface to which are attached a plurality of inwardly projecting fins. The innermost extension of the fins defines a centrally located well into which an automatic pipetting apparatus may be inserted. The method may be used for qualitative or quantitative determinations of the mobile component contained in a liquid which wets the solid phase matrix.