Eastman-kodak Company

John Figueras

Lee J Fleckenstein

Richard C Sutton

Margaret J Smith-Lewis

Roger W Nelson

Carl F Holtz

Peter W Scullard

Methods, compositions and elements for detecting a nitrogen-containing compound capable of releasing ammonia upon enzymatic action are described. The method comprises contacting in an aqueous medium a sample suspected of containing such a compound and a novel assay composition comprising at least one enzyme which catalyzes the decomposition of the compound to ammonia and detecting the ammonia by condensation with a diketone and measuring the color or fluorescence produced by the resulting dihydropyridine. The foregoing assay composition can be incorporated into single-layer or multilayer analytical elements of the type known in the prior art. A preferred such element comprises an isotropically porous spreading layer in fluid contact with a reagent layer. The spreading layer is most preferably non-fibrous.

Method, composition and element for the detection of nitrogen-containing

An element for the analysis of liquids contains a radiation-transmissive, detectable species migration-inhibiting layer interposed between a porous radiation-blocking layer and a radiation-transmissive reagent layer. All three layers are permeable to a predetermined analyte. The reagent layer contains a composition that provides a detectable species such as a dye in proportion to the concentration of the analyte that diffuses into the reagent layer from the overlying porous radiation-blocking layer. The detectable species migration-inhibiting layer acts to reduce the migration of, for example, dye from the reagent layer into the porous radiation-blocking layer, where the optical density of the dye cannot easily be measured. Optionally, the above-described three layers can be carried on a radiation-transmissive support, and other layers such as spreading layers, registration layers, and subbing layers can also be present in the element.

Reduction of detectable species migration in elements for the analysis

A dye-releasing mechanism is described which employs a nondiffusible dye-releasing compound having a dye or dye-precursor moiety attached thereto through a sulfonamido cleavage linkage so that a diffusible sulfonamide dye or dye-precursor will be released upon oxidation and subsequent alkaline hydrolysis of the compound.

Sulfonamido dye releasing compounds in photographic elements

A multilayer analytical element for the analysis of liquids, particularly small samples of biological liquids, having at least two layers including a reagent layer and a registration layer. The reagent layer contains an interactive composition including a nondiffusible material having a preformed detectable moiety, such composition being interactive in the presence of liquid containing an analyte of choice to provide a diffusible product comprising the preformed detectable moiety. The registration layer receives the diffusible product released from the reagent layer. The layers present in the analytical element are composed such that the detectable moiety released from the reagent layer or that remaining unreleased in the reagent layer can be selectively detected in the element. In one embodiment, there is disclosed an integral element which can include a support, preferably radiation-transmissive, on which a registration layer and a reagent layer are carried. Optionally, a spreading or analyte metering layer can be provided in the element adjacent the reagent layer to facilitate delivery of a uniform concentration of analyte to the reagent layer. In a preferred embodiment of this integral element, a radiation-blocking layer, permeable to the diffusible product, can be provided in the element intervening the reagent layer and the registration layer. The radiation-blocking layer, such as an opaque reflecting layer, can enhance the detection of the preformed detectable moiety in the registration layer or in the reagent layer by reflection densitometry or other appropriate radiometric technique. The multilayer element of the invention is particularly useful, for example, in the assay of amylase as well as a variety of other analytes.

Element for analysis of liquids

Interpolymers from monomers containing optical brightening moieties and solubilizing groups are useful in optical brightening compositions. Photographic elements containing these optical brightening compositions have excellent light stability.

Photographic silver halide elements containing optical brightening

Color photographic elements, compositions, diffusion transfer film units and processes are described which employ a nondiffusible p-sulfonamidoaniline or p-sulfonamidophenol which is preferably alkali-cleavable upon oxidation to release a diffusible color-providing moiety.

Growing community of inventors

Rochester, NY, United States of America

John Figueras