Abstract: A photographic element is disclosed comprised of a support and, coated on the support, at least one radiation-sensitive silver halide emulsion comprised of tabular silver halide grains and a dispersing medium. The emulsion includes as a vehicle methacrylate polymer latex capable of reducing pressure sensitivity having a glass transition temperature of less than 50.degree. C.

Abstract: Particular heterocyclic compounds are useful as color-forming couplers in analytical compositions, elements and methods. These compounds are represented by the structure: ##STR1## wherein R is a solubilizing group, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, alkyl, alkoxy, aryl, aryloxy, a heterocyclic group, halo, amino or R, and Z represents the carbon atoms necessary to complete the nucleus of a 5- or 6-membered fused ring. The color-forming coupler is combined with an oxidizable color developing compound, e.g. 4-aminoantipyrine to provide a chromogenic composition. This composition can be used in solution or dry assays of biological fluids to produce a color dye in the presence of hydrogen peroxide or other analytes, e.g. glucose or uric acid, which react to produce hydrogen peroxide.

Abstract: 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.

Abstract: Disclosed herein is an assay useful for the determination of an analyte in whole blood. In particular, this assay is useful for the quantitative determination of peroxide-generating analytes, such as glucose or cholesterol, in whole blood. This assay utilizes a multizone element consisting essentially of a support having thereon, in order and in fluid contact, a registration zone and a reagent/spreading zone. The reagent/spreading zone has a void volume and average pore size effective to accommodate whole blood, and contains an interactive composition necessary for the analysis. Such composition is capable of providing, upon interaction with the analyte, a dye which can be spectrophotometrically detected at a wavelength greater than about 600 nm.

Abstract: Disclosed herein is a dry analytical element and a method of using same for quantitatively detecting alkaline phosphatase in an aqueous liquid. The element comprises, in fluid contact, first and second reagent zones which can be self-supporting or carried on a support. The first reagent zone contains a substrate for alkaline phosphatase, e.g. p-nitrophenyl phosphate, and the second reagent zone contains a buffer which is an alkali metal or ammonium salt and has a pKa in the range of 9-11.5, e.g. an alkali metal salt of carbonic acid.

Abstract: Diazonium salts which are useful in an assay for bilirubin are disclosed. The novel salts have the structural formula: ##STR1## wherein X.sup.- is a stabilizing anion, Y is CO-- or SO.sub.2 --; and R.sup.1 and R.sup.2 are independently selected from hydrogen, alkyl, aryl, carboxyalkyl and hydroxyalkyl providing R.sup.1 and R.sup.2 are not both hydrogen; R.sup.3 and R.sup.4 are independently selected from groups such that the sum of the Hammett sigma values for R.sup.3 and R.sup.4 does not exceed +0.4 or R.sup.3 and R.sup.4 represent the carbon atoms necessary to complete a fused carbocyclic ring structure. Reagent compositions, analytical elements and methods which use the described diazonium salt are also disclosed.

Abstract: Elements for the analysis of aqueous liquids are described. Deterioration of test reagents, particularly peroxidase, during storage is reduced by inclusion in the elements of a co-polymer derived from hydrophobic, addition-polymerizable monomers.

Abstract: An analytical element for the detection of two or more analytes in an aqueous liquid. The element contains an essentially dry matrix, at least a portion of the matrix containing at least two interactive compositions, a first composition generating a first radiometrically detectable species corresponding to the presence and/or concentration of one analyte, and a second composition for the inhibition or the destruction of a second radiometrically detectable species corresponding to the presence and/or concentration of one of the other analytes. The first and second interactive compositions are positioned in the element matrix to be in liquid contact with one another. Each of the first and second detectable species produced in the element is selected to have a different, characteristic, detectable absorption or emission peak in the electromagnetic spectrum.