Eastman-kodak Company

Karl J Sanford

Jon N Eikenberry

Richard C Sutton

Susan J Danielson

John W Sutherland

Glen M Dappen

Michael W Sundberg

Paul H Frickey

Allen L Thunberg

Doyle E Hill

A heterogeneous, competitive binding immunoassay is conducted with a dry analytical element. The immunoassay is useful for determining a ligand (e.g. a therapeutic drug) and includes contacting a finite area of the element spreading layer with a sample of a liquid in the presence of a labeled ligand analog and an immobilized receptor. An immobilized ligand-receptor complex is formed within the finite area. Simultaneously, the uncomplexed ligand migrates horizontally away from the immobilized complex which remains in the center of the finite area. At least five seconds after the completion of the contacting, the amount of immobilized complex is measured in the center of the finite area.

Heterogeneous immunoassay utilizing horizontal separation in an

Disclosed herein is an assay for determination of albumin in a liquid sample. This assay involves the use of a dye of the structure: ##STR1## wherein n is zero or a positive integer up to 3; R.sup.1, R.sup.2 and R.sup.3 are independently hydrogen, alkyl, cycloalkyl, aryl, alkoxy, aroxy, hydroxy, carboxy, alkoxycarbonyl, amino or a nonaromatic heterocyclic group; and Z and Z.sub.1 independently represent the carbon, nitrogen, oxygen or sulfur atoms needed to complete a substituted or unsubstituted 5- to 7-membered carbocyclic or heterocyclic ring. This dye has a high affinity for albumin over a wide pH range. When the dye is bound to albumin, a shift in the dye spectral absorption occurs. Analytical elements containing this dye and an assay method are disclosed herein.

Method and element for albumin assay

Enzymes which are activated by pyridoxal phosphate are assayed in a dry analytical element which includes a high coverage of pyridoxal phosphate. The coverage of pyridoxal phosphate is such that the multiplication product of the coverage and the spreading coefficient of the element results in a reagent mixture concentration of at least about 0.9 mmole per liter when a liquid sample is contacted with the element thereby eliminating the need for a preincubation of the sample with a solution containing pyridoxal phosphate. The reactions for the determination of the enzymes are initiated by contact of the dry elements with a liquid sample.

Incorporation of pyridoxal phosphate in dry analytical elements for the

Analytical elements and methods for the selective determination of an analyte in aqueous fluids containing the analyte. These elements and methods feature means for continuously releasing chromogenic indicator reagent from a reagent zone to a reaction zone. The continuous release means is responsive to the application of a sample of the fluid to continuously release reagent into the reaction zone at a rate producing color response corresponding to interaction of the indicator with the analyte and reduced interaction of the indicator with interferents. In preferred embodiments, albumin is determined in the presence of interfering proteins such as globulins using buffered chromogenic indicator reagent. In such embodiments, when protein interferents are present, their interference can be substantially eliminated for up to three minutes, during which time color response is substantially only from the interaction of albumin and reagent. The determination of albumin follows from such color response.

Continuous release of reagent in an analytical element to reduce assay

The activity of an isoenzyme in a sample is determined by assaying for the isoenzyme in the presence of a predetermined concentration of an ionic amphiphile having a hydrophilic and a hydrophobic portion that has a discriminating effect on the activity of the isoenzyme and determining the activity of the isoenzyme present in the sample.

Assay method for isoenzyme activity

A multi-zone analytical element for the analysis of a proteinaceous or protein-bound substance contained in an aqueous liquid and a method of using the same are disclosed. The multi-zone element contains a spreading zone and a reagent zone in fluid contact. The reagent zone of the element contains an interactive composition. Incorporated in the spreading zone of the element is an immobilized polymeric material containing charge-bearing functional groups that, under conditions of use of the element, exhibit an electric charge opposite to that of said proteinaceous substance or the protein portion of said protein-bound substance.

Multi-zone analytical element and method using same

An improved analytical element for the detection of a predetermined analyte in an aqueous liquid under highly alkaline conditions is disclosed. The element features a stable, alkaline-providing composition. Preferably, the analytical element is a multi-zone element. The element is particularly useful in total protein analysis and, when so used, an improved biuret reagent composition for use therein is also provided. Methods of using the aforementioned analytical and biuret reagent composition are also disclosed.

Growing community of inventors

Rochester, NY, United States of America

Karl J Sanford