Determination of uric acid

Claim 1

A method for the quantitative analysis of uric acid in biological fluids consisting essentially of providing in continuous flow the sequential steps comprising: (a) combining, in continuous flow, a measured sample of a specimen of test fluid with an aqueous solution of an alkali metal or alkaline earth metal salt diluent; (b) passing the resulting mixture through a dialysis zone, thereby separating from said mixture a clear aqueous solution; (c) mixing said clear aqueous solution with a buffered uricase solution with a pH of 8.5 to 10; (d) incubating the resulting aqueous solution; (e) mixing at pH 5.5 to 8.5 the hydrogen peroxide produced in step (d), by sequential or concurrent flow, with a first reagent comprising a buffered aqueous solution of a chromogen in the leuco form consisting of an unsubstituted or nuclear-substituted benzidine or diphenyline and a second reagent comprising a buffered aqueous solution of peroxidase, thereby forming a colored solution; and (f) flowing said colored solution to an analyzing zone and photometrically determining quantitatively, during the flow of said colored solution through said analyzing zone, the uric acid content of the sample.

Claim 2

A method for the quantitative analysis of uric acid in biological fluids consisting essentially of providing in continuous flow the sequential steps comprising: (a) combining, in continuous flow, a measured sample of a specimen of test fluid with an aqueous solution of an alkali metal or alkaline earth metal salt diluent; (b) passing the resulting mixture through a dialysis zone, thereby separating from said mixture a clear aqueous solution; (c) mixing said clear aqueous solution with a buffered uricase solution with a pH of 8.5 to 10; (d) incubating the resulting aqueous solution; (e) mixing at pH 5.5 to 8.5 the hydrogen peroxide produced in step (d), by sequential or concurrent flow, with a first reagent comprising a buffered aqueous solution of a chromogen in the leuco form consisting of an unsubstituted or nuclear-substituted benzidine or diphenyline and a second reagent comprising a buffered aqueous solution of peroxidase, thereby forming a colored solution; and (f) flowing said colored solution to an analyzing zone and photometrically determining quantitatively, during the flow of said colored solution through said analyzing zone, the uric acid content of the sample.