Oxidative coupling dye for spectrophotometric quantitive analysis of analytes

• US 5,453,360 A
• Filed: 05/19/1994
• Issued: 09/26/1995
• Est. Priority Date: 02/03/1992
• Status: Expired due to Term

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Yu, Yeung S.
• Primary Examiner(s): Redding, David A.
• Assistant Examiner(s): Leary, Louise N.
• Application Number:
  US08/245,940
• Time in Patent Office: 495 Days
• Field of Search: 435/28, 435/25, 435/4, 435/20, 435/19, 435/11, 435/26, 435/14, 435/10, 435/12, 435/810, 435/966
• US Class Current: 435/28
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: C12Q 1/28 involving peroxidase
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: C12Q 2326/32 3-Methyl-2-benzothiazolinone hydrazone hydrochloride hydrate, i.e. MBTH
• CPC Class Codes: Y10S 435/81 Packaged device or kit

Abstract

A dye couple, comprising 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 8-anilino-l-naphthalenesulfonate (ANS), is used as an indicator in a reaction cascade producing a strong oxidizing agent, such as hydrogen peroxide or other peroxides or perborates. The strong oxidizing agent reacts with the dye couple to produce a blue dye stuff. The MBTH-ANS dye couple exhibits strong and flat spectral absorption at the region of about 600 to 650 nm. This region is free of blood color interference, which enables one to measure glucose and other analytes that react with an oxidase enzyme to produce the strong oxidizing agent, through the use of LED optics, accurately without much optic calibration. Further, the MBTH and ANS are very soluble in aqueous solution, yet become insoluble upon oxidative coupling. The poor solubility minimizes dye fading, thus providing a stable endpoint.

Claims

1. A test device containing a reaction pad to which a fluid to be analyzed is to be applied, said reaction pad including a hydrophilic matrix pad supported on a substrate holder, said reaction pad having pores containing a reagent system comprising an oxidase enzyme, a peroxidase, and a dye indicator comprising 3-methyl-2-benzothiazolinone hydrazone and 8-anilino-1-naphthalene sulfonate.

2. The test device of claim 1 wherein said oxidase enzyme is selected from the group consisting of glucose oxidase, cholesterol oxidase, uricase, alcohol oxidase, aldehyde oxidase, and glycerophosphate oxidase.

3. A test device containing a reaction pad to which an aqueous fluid to be analyzed is to be applied, said reaction pad including a hydrophilic matrix pad supported on a substrate holder, said reaction pad having pores containing a reagent system comprising an oxidase enzyme, a peroxidase, and a dye indicator, said dye indicator comprising 3-methyl-2-benzothiazolinone hydrazone and 8-anilino-1-napthalene sulfonate.

4. The test device of claim 3 wherein said oxidase enzyme is selected from the group consisting of glucose oxidase, cholesterol oxidase, uricase, alcohol oxidase, aldehyde oxidase, and glycerophosphate oxidase.

5. A method of determining analyte concentration in a liquid which comprises:

(a) quantitatively measuring baseline reflectance from a first surface of a reagent element comprising an inert, porous, hydrophilic, substantially reflective, single-layer matrix having pores of a size sufficient to exclude red blood cells and a reagent system which interact with said analyte to produce a light-absorbing reaction product, said reagent system being impregnated in the pores of said matrix, prior to application of said liquid to said reagent element;

(b) applying said liquid to a second surface of said reagent element and allowing said liquid to migrate from said second surface to said first surface;

(c) quantitatively measuring reaction reflectance from said first surface of said reagent element without removing excess sample or non-migrating components of said sample from said second surface;

(d) quantitatively measuring reflectance of interfering substances from said first surface of said reagent element using a wavelength of light reflected by interfering substances and different from the wavelength of light used to measure said reaction product reflectance in order to correct for background reflectance at the reaction product wavelength caused by interfering substances; and

(e) calculating a value expressing said analyte concentration from said reflectance measurements, wherein said reaction system includes a dye couple consisting essentially of 3-methyl-2-benzothiazolinone hydrazone and 8-anilino-l-naphthalene sulfonate and at least one reagent capable of reacting with said analyte to produce a strong oxidizing agent which reacts with said dye couple to form a blue dye.

6. The method of claim 5 wherein said strong oxidizing agent is selected from the group consisting of hydrogen peroxide and peroxides.

7. The method of claim 6 wherein said organic peroxides are selected from the group consisting of cumene hydrogen peroxide, urea hydrogen peroxide, benzoyl peroxide, and perborates.

8. The method of claim 6 wherein said analyte comprises glucose and said reaction system further includes glucose oxidase and peroxidase.

9. A method of determining analyte concentration in a liquid which comprises:

(a) quantitatively measuring baseline reflectance from a first surface of a reagent element comprising an inert, porous, hydrophilic, substantially reflective, single-layer matrix having pores of a size sufficient to exclude red blood cells and a reagent system which interact with said analyte to produce a light-absorbing reaction product, said reagent system being impregnated in the pores of said matrix, prior to application of said liquid to said reagent element;

(b) applying said liquid to a second surface of said reagent element and allowing said liquid to migrate from said second surface to said first surface;

(c) quantitatively measuring reaction reflectance from said first surface of said reagent element without removing excess sample or non-migrating components of said sample from said second surface;

(d) quantitatively measuring reflectance of interfering substances from said first surface of said reagent element using a wavelength of light reflected by interfering substances and different from the wavelength of light used to measure said reaction product reflectance in order to correct for background reflectance at the reaction product wavelength caused by interfering substances; and

(e) calculating a value expressing said analyte concentration from said reflectance measurements, wherein said analyte comprises a substance that reacts with an enzyme to produce hydrogen peroxide and said reagent system comprises said enzyme, peroxidase and 3-methyl-2-benzothiazolinone hydrazone and 8-anilino-1-naphthalene sulfonate.

10. The method of claim 9 wherein said analyte comprises a substance selected from the group consisting of glucose, cholesterol, uric acid, methanol, ethanol, formaldehyde, and glycerol-3-phosphate.

11. The method of claim 9 wherein said enzyme is selected from the group consisting of glucose oxidase, cholesterol oxidase, uricase, alcohol oxidase, aldehyde oxidase, and glycerophosphate oxidase.

12. In a method for determining glucose in a blood sample employing a membrane and a signal-producing system which reacts with glucose to produce a light-absorptive dye product, said system being bound to the membrane, and in which the amount of said dye product is determined by means of a reflectance measurement from a surface of said membrane, said method comprising:

(a) applying an unmeasured whole blood sample to a first surface of a single-layer, substantially reflective, porous, hydrophilic membrane having pores of a size sufficient to exclude red blood cells and which contains said signal-producing system;

(b) making said reflectance measurement on a second surface of said membrane other than the surface to which said sample is applied without removing excess sample or red blood cells from said first surface; and

(c) determining the concentration of glucose in said sample from said reflectance measurement, wherein the improvement comprises employing as said signal-producing system glucose oxidase, peroxidase and 3-methyl- 2-benzothiazolinone hydrazone and 8-anilino-1-naphthalene sul-fonate.

13. A method for determining glucose comprising the steps of:

(a) applying a whole blood sample to an application site on a reagent element wherein said reagent element comprises a single-layer, substantially reflective, porous, hydrophilic matrix which filters out red blood cells and to which is bound a signal-producing system comprising glucose oxidase, peroxidase, and a dye indicator, which signal-producing system reacts with glucose to form a reaction dye product;

(b) allowing the sample to migrate to a reading site on said membrane different from said application site;

(c) monitoring reflectance at said reading site for a decrease in reflectance indicative of sample presence in said reading site in order to initiate timing of an incubation period; and

(d) determining the change in reflectance at said reading site during the incubation period as a measure of dye product formed to determine the amount of glucose in said sample, in which all reflectance measurements at said reading site are performed without removing excess sample or red blood cells from said application site and at least one measurement is taken at a wavelength at which light is absorbed by said dye product, wherein said dye indicator comprises 3-methyl-2-benzothiazolinone hydrazone and 8-anilino-1-naphthalene sulfonate.