TEST DEVICE FOR DETECTING LOW CONCENTRATIONS OF SUBSTANCES IN FLUIDS

• US 3,811,840 A
• Filed: 04/01/1969
• Issued: 05/21/1974
• Est. Priority Date: 04/01/1969
• Status: Expired due to Term

• Current Assignee: Chauncey Orvis Rupe, Richard Gordon Rosenfield, Robert Bauer
• Original Assignee: Chauncey Orvis Rupe, Richard Gordon Rosenfield, Robert Bauer
• Inventors: Bauer, Robert, Rosenfield, Richard Gordon, Rupe, Chauncey Orvis
• Primary Examiner(s): Scovronek, Joseph
• Application Number:
  US04/811,935
• Time in Patent Office: 1,876 Days
• Field of Search: 23/253TP,23B 116/114AM
• US Class Current: 422/407
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 31/22 using chemical indicators G01N31/02 takes precedence
• CPC Class Codes: G01N 33/521 Single-layer analytical elements
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• CPC Class Codes: Y10T 436/173845 Amine and quaternary ammonium
• CPC Class Codes: Y10T 436/193333 In aqueous solution
• CPC Class Codes: Y10T 436/201666 Carboxylic acid

Abstract

Test device for detecting low concentrations of substances in test fluids comprising an absorbent wick having a substantially flat surface portion enclosed in a fluid impervious sheath having an aperture of predetermined limited area formed therein, the aperture being contiguous to and exposing a predetermined limited area of the flat surface portion of the wick, which portion is incorporated with a reagent specifically reactable with the substance being detected. In use the device is immersed into the test fluid so that the aperture is submerged and the device, allowed to remain therein while the test fluid contacts the reagent area adjacent to the aperture and migrates into the remainder of the wick. The reagent is immobilized with respect to the liquid. The sheath adjacent to the wick is opaque.

Claims

2. A test device as in claim 1 wherein the wick is a bibulous cellulose material.

3. A test device as in claim 2 wherein the cellulose material is paper.

4. A test device as in claim 1 wherein the sheath is a semi-rigid polymeric film selected from the group of substances consisting of polyethylene, polypropylene, polyvinyl chloride, polyvinyl acetate, polyamide, polyethylene terephthalate and various combinations thereof.

5. A test device as in claim 1 wherein a portion of the wick at said aperture is detachable from the remainder of said wick, said detachable portion being incorporated with the said reagent.

6. A test device as in claim 1 wherein said reagent is an ion-exchange resin.

7. A dip-and-read type device for detecting free chlorine in a liquid which comprises a liquid impervious sheath;

a liquid absorbent wick capable of accommodating a predetermined volume of liquid, said wick having a substantially flat surface portion and being enclosed within said sheath, said sheath being formed with an aperture of predetermined limited area contiguous to and exposing to said liquid a predetermined limited area of said flat surface portion of said wick, the entire sheath portion adjacent to the wick being opaque; and

a reagent incorporated with the portion of the wick exposed at the aperture, which reagent is immobilized with respect to said liquid and is specifically reactable with free chlorine to give a chromogenic response to said aperture to the presence of free chlorine in said liquid.

8. A test device as in claim 7 wherein the reagent is an oxidation-reduction indicator.