Bayer Healthcare LLC

Siemens Healthcare Diagnostics Gmbh

Alexander H Orn

James Arthur Profitt

Jennifer Farr

A method of applying an organic acid reagent having limited transolubility in organic solvents, aqueous solvents, and mixtures thereof to a component of a diagnostic test device by mixing an organic acid reagent and an amine to form a salt complex, dissolving the salt complex in a solvent to release the organic acid reagent into the solvent, and applying the solvent to the component of the diagnostic test device such that the organic acid reagent present in the solvent becomes integrated into the diagnostic test device. The amine is represented by the formula HNRwherein m is 0, 1, or 2; n is 1, 2, or 3; the sum of m and n is 3; and R is an independently selected group which renders the salt complex soluble in aqueous solvents, organic solvents, or mixtures thereof. The amine is also represented by the formula NRwherein R is an independently selected group which renders the salt complex soluble in aqueous solvents, organic solvents, or mixtures thereof. The organic acid reagent is selected from a carboxylic acid, a sulfonic acid, a phosphoric acid, and mixtures thereof. Preferred reagents are dyes like pyragallol red. In a specific embodiment the diagnostic test device is a paper test strip.

Absorbing organic reagents into diagnostic test devices by formation of amine salt complexes

An assay for the determination of protein in an aqueous test fluid which combines the test fluid with a buffer and a dye. The buffer is selected from citrulline, malonic acid, cyanoacetic acid, citraconic acid, methyl phosphonic acid, sarcosine, saccharin, or combinations thereof. The buffer is added in sufficient quantity to maintain the pH of the assay including the test fluid at a selected target pH range within a range of from about 2.0 to about 3.0. The dye has a pKa which enables it to operate as a protein indicator at the target pH range. The dye also has affinity for protein such that it will provide a detectable response in the presence of greater than about 15 mg/dL protein to thereby render the assay suitable for the detection of total protein in the test fluid. The buffer and dye may be absorbed in a test strip of absorbent material.

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Nappanee, IN, United States of America

Alexander H Orn