Method, composition, and device for determining the specific gravity of a liquid

• US 4,076,502 A
• Filed: 06/14/1976
• Issued: 02/28/1978
• Est. Priority Date: 02/14/1975
• Status: Expired due to Term

• Current Assignee: Miles Laboratories, Inc. (Bayer AG)
• Original Assignee: Miles Laboratories, Inc. (Bayer AG)
• Inventors: Dugle, James B., Hager, C. Bradley
• Primary Examiner(s): Reese, Robert M.
• Application Number:
  US05/696,050
• Time in Patent Office: 624 Days
• Field of Search: 23/253 TP, 23/230 R, 195/103.5 C, 252/408
• US Class Current: 435/14
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: C12Q 1/54 involving glucose or galactose

Abstract

A method, composition, and device for determining the specific gravity of a liquid. In the method, a sample of the liquid to be tested is contacted with standardized quantities of substances which participate in a reaction that is affected by the level of solute in said liquid. The resulting effect of the solute on the reaction is a reproducible function of the concentration or amount of solute in the sample and relates to the specific gravity of the liquid tested. A unitized test composition is provided comprising at least one substance which participates in the standardized reaction. The standardized reaction is preferably chemical in nature and, in such a case, the test composition preferably includes an indicator responsive to a product of the chemical reaction.

Claims

1. A method for determining the specific gravity of a urine sample, which method comprises the steps of:

(a) contacting said sample with a predetermined concentration of an enzyme and of a reagent upon which said enzyme exerts its catalytic activity, the rate of reaction of said reagent in the presence of said enzyme being affected by the aggregate solute content of said sample,

(b) determining the rate of said reaction in contact with said sample, and

(c) comparing such determined reaction rate to the rates of said reaction when carried out in contact respectively with samples of urine having known different specific gravities.

2. A method as in claim 1 wherein the rate of said reaction is determined by measuring the rate of formation of a product of said reaction.

3. A method as in claim 2 wherein the rate of formation of said reaction product is measured by contacting said sample with indicator means responsive to the presence of said product and determining the rate of indicator response.

4. A method as in claim 2 wherein the response of said indicator means is colorimetric.

5. A method as in claim 4 wherein step (c) is accomplished by comparing with a standard color chart the color response of said indicator means at a predetermined time interval after contact of said sample with said indicator means.

6. A method as in claim 1 wherein said enzyme is an oxidoreductase.

7. A method as in claim 6 wherein said reaction involves the enzymatic oxidation of a carbohydrate to produce hydrogen peroxide.

8. A method as in claim 7 wherein said reagent is a hexose.

9. A method as in claim 7 wherein said enzyme is galactose oxidase and said reagent is galactose.

10. A method as in claim 7 wherein said enzyme is glucose oxidase and said reagent is glucose.

11. A test composition for determining the specific gravity of a urine sample, which composition comprises (1) a predetermined quantity of an enzyme and of a reagent upon which said enzyme exerts its catalytic effect, the rate of reaction of said reagent in the presence of said enzyme being affected by the aggregate solute content of said sample, and (2) indicator means responsive to the presence of a product of said reaction.

12. A composition as in claim 11 wherein the response of said indicator means is colorimetric.

13. A composition as in claim 11 which is in a dry form.

14. A test device for determining the specific gravity of a urine sample, which comprises the test composition of claim 11 and a carrier incorporated therewith.

15. A test device as in claim 14 wherein said carrier is absorbent relative to said sample.

16. A test device as in claim 14 which additionally comprises a base to which said carrier is attached.

17. A test device as in claim 14 which is prepared by impregnating said carrier with a first solution containing one of said enzyme and said reagent of said test composition, drying said carrier, impregnating said carrier with at least one other solution which contains the other of said enzyme and reagent and in which said reaction is incapable of occurring to a significant degree, and drying said carrier.

18. A test device as in claim 14 wherein the components of said test composition are dispersed in a material which is soluble in said sample.

19. A composition as in claim 11 wherein said enzyme is an oxidoreductase.

20. A composition as in claim 19 wherein said reaction involves the enzymatic oxidation of a carbohydrate to produce hydrogen peroxide.

21. A composition as in claim 20 wherein said indicator means is responsive to the presence of hydrogen peroxide and includes a substance having peroxidative activity and a chromogen which is oxidized in the presence of hydrogen peroxide and said substance having peroxidative activity to yield a colorimetric response.

22. A method as in claim 20 wherein said reagent is a hexose.

23. A method as in claim 20 wherein said enzyme is galactose oxidase and said reagent is galactose.

24. A method as in claim 20 wherein said enzyme is glucose oxidase and said reagent is glucose.

25. A test device for determining the specific gravity of a urine sample, which comprises a base, at least two carriers supported by said base, one of said enzyme and said reagent of the test composition of claim 11 being incorporated with at least one of said carriers, and the other of said enzyme and reagent being incorporated with at least one other of said at least two carriers.

26. A test device as in claim 25 wherein said carriers are attached to said base in laminate relation.

27. A test device as in claim 25 wherein at least one of said at least two carriers is incorporated with indicator means responsive to the presence of a product of said reaction.

28. A test device as in claim 27 wherein the response of said indicator means is colorimetric.

29. A test device as in claim 25 wherein said carriers are attached to said base.

30. A test device as in claim 29 wherein said carriers are spaced apart and movable into contact with one another.

31. A test device as in claim 29 wherein said carriers are in physical contact with each other.