Ion activity measuring device and method for producing the same

• US 6,905,653 B1
• Filed: 12/28/1999
• Issued: 06/14/2005
• Est. Priority Date: 10/31/1996
• Status: Expired due to Fees

• Current Assignee: ARKRAY, Inc
• Original Assignee: ARKRAY, Inc
• Inventors: Higuchi, Yoshihiko
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): CROSS, LATOYA I
• Application Number:
  US09/473,165
• Time in Patent Office: 1,995 Days
• Field of Search: 422/56, 422/57, 422/58, 422/61
• US Class Current: 422/421
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements

Abstract

Determining a substance to be measured in a liquid sample by measuring the degree of coloring obtained when the substance is subjected to coloring reaction in terms of reflectance. Polymer beads embedding light reflective particles are contained in a reagent layer of the dry measuring test device, or a light blocking layer containing light blocking particles, preferably polymer beads embedding the light blocking particles, is laminated on the reagent layer of the dry measuring test device. The reagent layer comprises a reagent containing a chromogen and a matrix which retains the reagent in the form of a layer, for determining the substance to be measured in the liquid sample by measuring the degree of coloring of the chromogen generated through the reaction between the substance and the reagent in terms of reflectance of light entered into the reagent layer. Speedy and highly accurate measurement is obtained in shortening measuring time by measuring reflectance corresponding to a low degree of coloring or by reducing influence of solid matter contained in the liquid sample on absorption and scattering of the measuring light and influence of external stray light entered from the opposite side of the surface of the light measuring part.

Claims

1. A dry measuring test device, comprising a reagent layer comprising a reagent containing a chromogen and a matrix which retains said reagent in the form of a layer, for determining a substance to be measured in a liquid sample by measuring the degree of coloring of the chromogen generated through the reaction between the substance to be measured and the reagent in terms of reflectance of light entered into the reagent layer, wherein a light blocking layer containing light blocking particles in the form of polymer beads embedding the light blocking particles is laminated on the reagent layer, wherein the light blocking particles are carbon black.

2. The dry measuring test device as claimed in claim 1, wherein the light blocking particles are contained in an amount of 15 to 90 wt % based on the total weight of the light blocking layer.

3. The dry measuring text device as claimed in claim 1, wherein said polymer beads contain as a main component a compound selected from the group consisting of:

polymer or copolymer having as a main component monomers selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, ester of these substances, styrene, and alkylstyrene;

polyurethane;

polyurea;

polyethylene;

polypropylene; and

polyvinyl chloride.

4. The dry measuring test device as claimed in claim 1, wherein the light blocking particles are contained in an amount of 10 to 70 w/v % based on the total content of the polymer beads, and the polymer beads are contained in the light blocking layer in an amount of 30 to 90 wt % based on the total weight of the light blocking layer.

5. The dry measuring device as claimed in claim 1, wherein an average particle diameter of the polymer beads ranges from 1 to 40 μ

m.

6. The dry measuring test device as claimed in claim 1, wherein the reagent layer further contains polymer beads embedding the light reflective particles.