Determination of Uric Acid

Abstract An automated method is described for the determination of uric acid by a carbonate method. Since uric acid is separated from proteins by dialysis, the loss of uric acid due to protein precipitation in manual methods is avoided. There is no appreciable interference from salicylates, high levels of blood sugar, or ascorbic acid. The method shows an acceptable correlation with the uricase method.

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Simplified Automated Method for Determination of Urinary or Serum Uric Acid, Based on Reduction of Ferric-Phenanthroline Complex

Clinical Chemistry ◽

10.1093/clinchem/21.1.125 ◽

1975 ◽

Vol 21 (1) ◽

pp. 125-129 ◽

Cited By ~ 3

Author(s):

John W Nelson ◽

K K Batra

Keyword(s):

Ascorbic Acid ◽

Uric Acid ◽

Reduction Method ◽

Phosphotungstic Acid ◽

Colorimetric Method ◽

Automated Method ◽

Phenanthroline Complex ◽

Acidic Conditions ◽

Acid Reduction

Abstract We describe an automated colorimetric method for determination of uric acid in serum or urine by use of an AutoAnalyzer II or SMA 12/60 (Technicon Corp.). The method depends on reduction of a ferric-phenanthroline complex by uric acid under acidic conditions to a ferrous-phenanthroline complex, which absorbs at 505 nm. Advantages of this method over other methods now in use are that color and concentration are linearly related (to 20 mg/100 ml); aqueous reagents are easily prepared, stable, and inexpensive; and interference from ascorbic acid has been eliminated by use of an alkaline copper-containing diluent. The analysis is also free of interference from glucose, creatinine, glutathione, salicylates and hemoglobin. Correlation with results of the Technicon phosphotungstic acid reduction method is excellent (r = .996). Correlation with results of an automated uricase method is satisfactory (r = .979). Recovery of uric acid was 101% over a wide concentration range.

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Modified Glucose Oxidase Method for Determination of Glucose in Whole Blood

Clinical Chemistry ◽

10.1093/clinchem/19.3.308 ◽

1973 ◽

Vol 19 (3) ◽

pp. 308-311 ◽

Cited By ~ 10

Author(s):

Samuel Meites ◽

Karen Saniel-Banrey

Keyword(s):

Ascorbic Acid ◽

Uric Acid ◽

Glucose Oxidase ◽

Whole Blood ◽

Enzyme Concentration ◽

Capillary Blood ◽

Protein Precipitation ◽

Analytical Time

Abstract We have modified an ultramicro method for determining glucose with glucose oxidase—peroxidase—odianisidine. Capillary blood is diluted in isotonic NaF (17.6-17.8 g/ liter), the cells are removed, and glucose is determined after a 20-min incubation with enzyme-containing reagent. Increasing the enzyme concentration fourfold nullifies interference from ascorbic acid and hemolysis, while greatly decreasing interference from bilirubinemia. If necessary, bilirubin is removed completely by coprecipitation with protein. Interference from uric acid is minimized by incorporating it into the standards. Several other suspected interferences proved inconsequential. Isotonic NaF does not inhibit the enzymes used, and preserves glucose in blood for at least 2 h. Avoiding protein precipitation and shortening the incubating time significantly lessens analytical time without affecting precision.

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