APPARATUS AND METHOD FOR MEASURING CONDUCTIVITY CHANGE IN A GLUCOSE-GLUCOSE OXIDASE REACTION

• US 3,839,154 A
• Filed: 08/20/1973
• Issued: 10/01/1974
• Est. Priority Date: 08/20/1973
• Status: Expired due to Term

• Current Assignee: Ralph A. Messing
• Original Assignee: Ralph A. Messing
• Inventors: Messing, Ralph A.
• Primary Examiner(s): Tanenholtz, Alvin E.
• Application Number:
  US05/390,005
• Time in Patent Office: 407 Days
• Field of Search: 195/13.5R,127,DIG.11
• US Class Current: 435/14
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

Changes in the electrical conductivity of a solution containing the reaction products of a glucose-glucose oxidase reaction can be continuously monitored without interference from the enzyme by passing a glucose solution through a column containing glucose oxidase and catalase immobilized on and within porous inorganic carrier materials, measuring the conductivity of the solution after passage through the column, and comparing that conductivity with the conductivity of the glucose solution before passage through the column or the conductivity of a standard glucose solution.

Claims

1. AN APPARATUS FOR MONITORING THE ELECTRICAL CONDUCTIVITY OF A SOLUTION CONTAINING THE PRODUCTS OF A GLUCOSE-GLUCOSE OXIDASE REACTION COMPRISING IN COMBINATION:

A. FIRST AND SECOND FLOW-THROUGH CELLS, EACH CELL HAVING A CHAMBER THROUGH WHICH AN IONIC SOLUTION CAN FLOW AND A PAIR OF ELECTRODLES EXPOSED TO THE CHAMBER AND ADAPTED TO MEASURE THE ELECTRICAL CONDUCTIVITY OF AN IONIC SOLUTION WITHIN THE CHAMBER;

B. A FLOW-THROUGH CONTAINER CONTAINING AN ENZYME COMPOSITE COMPRISING GLUCOSE OXIDASE AND CATALASE IMOBILIZED WITHIN THE PORES OF POROUS, ESSENTIALLY WATER-INSOLUBLE INORGANIC CARRIER PARTICLES HAVING AN AVERAGE PORE DIAMETER BETWEEN ABOUT 220A AND 985A AND AN AVERAGE PARTICLE SIZE BETWEEN ABOUT 25 AND 80 MESH, U.S. STANDARD SIEVE;

C. MEANS FOR INTRODUCING A GLUCOSE-CONTAINING SOLUTION INTO THE CONTAINER OF (B) AND MEANS FOR COLLECTING THE SOLUTION AFTER PASSAGE THROUGH THE CONTAINER OF (B) AND PASSING THE COLLECTED SOLUTION THROUGH THE FIRST FLOWTHROUGH CELL;

D. MELANS FOR MEASURING THE ELECTRICAL CONDUCTIVITY OF A SOLUTION WITHIN THE FIRST CELL;

E. MEANS FOR PASSING EITHER A STANDARD GLUCOSE SOLUTION OR THE GLUCOSE-CONTAINING SOLUTION PRIOR TO PASSAGE THROUGH THE CONTAINER OF (B) THROUGH THE SECOND CELL AND MEASURING THE ELECTRICAL CONDUCTIVITY OF EITHER SUCH SOLUTIONS WITHIN THE SECOND CELL;

AND, F. MEANS FOR MEASURING THE DIFFERENCE IN ELECTRICAL CONDUCTIVITY BETWEEN THE FIRST AND SECOND CELL.

2. The apparatus of claim 1 wherein the container of (b) is a plug flow-through column containing enzyme composite of glucose oxidase and catalase adsorbed within the pores of porous titania particles having an average pore diameter between about 220A and 400A.

3. The apparatus of claim 1 wherein there is included recorder means electrically associated with the means for measuring the difference in conductivity between the first and second cells.

4. A method of monitoring the change in electrical conductivity of a solution which change is attributable to a glucose-glucose oxidase reaction which comprises the steps of:

a. passing a glucose-containing solution through a flow-through container containing composites of glucose oxidase and catalase immobilized within the pores of porous, essentially water-insoluble inorganic carrier particles having an average pore diameter between about 220A and 985A and an average particle size between about 25 and 80 mesh, U.S. Standard Sieve;

b. measuring the electrical conductivity of the solution after passage through the container; and

c. determining the difference between that conductivity and that of a standard glucose solution or the conductivity of the glucose-containing solution prior to passage through the flow-through container.

5. The method of claim 4 wherein the flow-through container is a plug flow-through column containing composites of glucose oxidase and catalase adsorbed within the pores of porous titania particles having an average pore diameter of between about 220A and 400A.