Eastman-kodak Company

Johnson & Johnson Clinical Diagnostics, Inc.

Clinical Diagnostic Systems, Inc.

Thomas C Arter

James R Schaeffer

Ignazio S Ponticello

Merrit Nyles Jacobs

Harold C Warren

John C Mauck

Eugene H Barbee

Robert F Winterkorn

Mohan S Saini

Paul A Kildal-Brandt

Karen L Warren

Bonny A Harris

A spectrophotometric assay for the detection of acetaminophen in aqueous fluids can be carried out with a dry analytical element. The element comprises a support having thereon one or more reagent layers containing a first enzyme, aryl acylamidase, to cleave the amide bond of acetaminophen to produce p-aminophenol; a second enzyme, ascorbic acid oxidase, to oxidize the p-aminophenol so that it couples to a water soluble coupling agent to form a dye that is read at 670 nm. The assay is precise, accurate on serum and plasma samples, and relatively free from significant interferences. The element also allows measurement over a broad dynamic range.

Dry analytical element for acetaminophen assay

A dry analytical element has been prepared for the assay of prostatic acid phosphatase at a pH of from about 3 to about 6.5. The element can be a single porous spreading zone or a multilayer structure. Within the element is a relatively nonhygroscopic aromatic phosphate substrate for the analyte which produces a phenol reaction product. This product is reacted with a diazonium or tetrazolium salt, also in the element, to produce a chromophore for detection. A buffer in the element maintains it at the proper pH during the assay.

Dry analytical element and method for the detection of prostatic acid

A method for reducing interferent bias such as hemoglobin bias in immunoassays using dried slide test elements featuring peroxidase and leuco dye as the labeling mechanism. The method features the steps of: a) calibrating an immunoassay of a target analyte by ascertaining the time at which the rate of change in density produced by a first set of the test elements for the target analyte on at least one liquid having a known amount of interferent of choice and a known amount of target analyte, crosses over or minimizes the difference compared to the rate of change in density produced by a second set of test elements substantially identical to the first set of test elements, on a liquid having the known amount of target analyte but a negligible amount of interferent of choice, and b) conducting an assay of a patient sample of unknown amount of the target analyte by reading the rate of change in density in a third set of the test elements substantially identical to the first and second sets, caused by the sample, at a time corresponding to the cross-over time ascertained in step a).

Calibrating and testing immunoassays to minimize interferences

A multilayer analytical element for measuring salicylate is disclosed. The element has a support. The support is coated with the following layers, top down to the support: a) a spreading layer, b) a dye layer having a pH greater than 6.5 and comprising tyrosinase and a water-insoluble hydrazone coupling agent, c) a barrier layer that prevents passage of molecules having a molecular weight in excess of 5,000, and d) a reagent layer comprising salicylate hydroxylase and nicotinamide adenine dinucleotide (NADH), wherein the spreading layer comprises valproic acid, 8-anilino-1-naphthalenesutfonic acid (ANS) or the magnesium salt of 8-anilino-1-naphthalenesulfonic acid.

Multilayer analytical element for salicylate assay

A dry multilayer element for assaying salicylate is disclosed.

Dry analytical element for assaying salicylate

Reticulation caused by swelling with processing solutions in photographic elements is reduced for elements containing at least two contiguous gelatin-containing layers wherein the uppermost layer has a lateral swell coefficient at least 10% greater than the lower gelatin-containing layer before polymer addition and wherein said uppermost layer comprises an essentially non-diffusible vinyl polymer having reactive groups which crosslink by reaction with primary amine or secondary amine groups on gelatin or a water-soluble, non-diffusible amine containing vinyl polymer and a hardener for gelatin. These elements are particularly useful in photographic products.

Reduction of reticulation in gelatin-containing elements

In the drying of sheet materials which have been coated with a layer, or with two or more superposed layers, of liquid coating composition, improved drying conditions which result in less formation of mottle are provided by the use of a foraminous shield, such as a screen or perforated plate, located in close proximity to the coated surface. The sheet material, for example a web of paper or polymeric film or a succession of discrete sheets of paper or polymeric film is conveyed through a drying zone, along a predetermined path, while a gaseous drying medium, such as air maintained at an elevated temperature, which serves to promote evaporation of the liquid medium in the coating composition, is directed through the foraminous shield onto the coated surface. The foraminous shield functions to promote uniform heat transfer conditions and restricts the extent to which spent gaseous drying medium, which is discharged from the drying zone, comes into contact with the surface of the coating, thereby minimizing mottle formation. While the foraminous shield is useful in any drying operation in which mottle formation is a problem, it is especially advantageous in the drying of photographic materials, particularly those comprising one or more layers formed from coating compositions that contain volatile organic solvents.

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Rochester, NY, United States of America

Thomas C Arter