Dry analytical element containing ampholyte

• US 5,709,837 A
• Filed: 10/19/1995
• Issued: 01/20/1998
• Est. Priority Date: 10/19/1994
• Status: Expired due to Term

• Current Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Ogawa, Masashi, Mori, Toshihiro, Amano, Yoshikazu
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/545,233
• Time in Patent Office: 824 Days
• Field of Search: 422/56-58, 422/61, 436/98, 436/108
• US Class Current: 422/423
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• CPC Class Codes: Y10T 436/147777 Plural nitrogen in the same ring [e.g., barbituates, creatinine, etc.]
• CPC Class Codes: Y10T 436/171538 Urea or blood urea nitrogen

Abstract

A dry analytical element comprising at least one water-permeable reagent layer and a porous spreading layer laminated in this order on a support, wherein at least one layer which is the water-permeable reagent layer, the porous spreading layer or an optional water-permeable layer contains a water-soluble polybasic amino carboxylic acid which is an ampholyte. By applying an analytical element of the invention, an analyte can be measured at a high sensitivity using a small amount of an enzyme, etc., and shelf file can be extended.

Claims

1. A dry analytical element comprising, laminated in this order, a support, at least one water-permeable reagent layer and a porous spreading layer, wherein at least one layer contains a water-soluble polybasic amino carboxylic acid which is an ampholyte having the formula R--NH--(CH₂ CH₂ --N)--_n H, wherein R is H or --(CH₂ --)_m COOH, provided that m is 1 or 2, and n is 3, 4 or 5.

2. The dry analytical element of claim 1, wherein said n is 5, R is H or --CH₂ CH₂ COOH and the molar ratio of --COOH:

--NH-- and --NH₂ is 1;

6 to 6;

6.

3. The dry analytical element of claim 1, wherein the layer containing said ampholyte is adjusted so as to have a predetermined pH value in a range of pH 5.0 to 9.5 upon spotting a liquid sample.

4. The dry analytical element of claim 1, wherein said support is a water-impermeable transparent support.

5. The dry analytical element of claim 1 which further comprises an additional water-permeable layer, which layer contains the ampholyte.

6. The dry analytical element of claim 1, wherein said ampholyte is a water-soluble polybasic amino carboxylic acid synthesised by reacting an organic compound having at least two amino or imino groups reacting with a carboxylic acid ester having a carbon-carbon double bond in a nonaqueous solvent, and then hydrolyzing the ester portion.

7. The dry analytical element of claim 6, wherein the layer containing said ampholyte is adjusted so as to have a predetermined pH value in a range of pH 5.0 to 9.5 upon spotting a liquid sample.

8. The dry analytical element of claim 6, wherein said support is a water-impermeable transparent support.

9. The dry analytical element of claim 6, which consists essentially of a water-impermeable transparent support, an indicator layer, a porous liquid barrier layer, an ammonia-producing reagent layer, an ammonia diffusion-preventing layer, an endogeneous ammonia-trapping layer, and the spreading layer integrally laminated in this order, wherein said ampholyte is incorporated into the endogeneous ammonia-trapping layer.

10. The dry analytical element of claim 8, wherein a reagent composition for the detection of creatinine is incorporated into the ammonia-producing reagent layer.

11. The dry analytical element of claim 1 comprising at least one water-permeable reagent layer and a porous spreading layer for spreading whole blood wherein the spreading layer contains a hemolytic reagent.

12. The dry analytical element of claim 11 which contains a reagent composition for determination of a member selected from the group consisting of creatinine, urea nitrogen, inorganic phosphorus and bicarbonate salts.

13. The dry analytical element of claim 11 which contains a reagent composition for the determination of creatinine or urea nitrogen.

14. The dry analytical element of claim 11, wherein said hemolytic reagent is a surfactant.

15. The dry analytical element of claim 14, wherein the content of said surfactant is 1 to 50 g/m².

16. The dry analytical element of claim 14, wherein the content of said surfactant is 1 to 50 g/m².

17. The dry analytical element of claim 14, wherein said surfactant is a nonionic surfactant.

18. The dry analytical element of claim 17, wherein said nonionic surfactant is alkylphenoxypolyethoxyethanol.

19. A dry analytical element which consists essentially of a water-impermeable transparent support, an indicator layer, a porous liquid barrier layer, an ammonia-producing reagent layer, an ammonia diffusion-preventing layer, an endogenous ammonia-trapping layer, and a spreading layer, integrally laminated in this order, and having an ampholyte having the formula R--NH.paren open-st.CH₂ CH₂ --N.paren close-st._n H, wherein R is H or .paren open-st.CH₂ .paren close-st._m COOH, provided that m is 1 or 2, and n is 3, 4 or 5 incorporated into the endogenous ammonia-trapping layer.

20. The dry analytical element of claim 19, wherein a reagent composition for the detection of creatinine is incorporated into the ammonia-producing reagent layer.