Potentiometric oxygen sensor

Claim 2

A SENSOR FOR DETERMINING THE PARTIAL PRESSURE OF OXYGEN IN A FLUID SAMPLE, COMPRISING: A. A FIRST MEASURING ELECTRODE WHOSE POTENTIAL DEPENDS ON OXYGEN CONCENTRATION IN A MEDIUM CONTACTING IT AND IS SELECTED FROM THE GROUP CONSISTING OF TUNGSTEN, MOLYBDENUM AND TANTALUM AND ALLOYS THEREOF, B. A SILVER-SILVER HALIDE REFERENCE ELECTRODES SPACED FROM SAID FIRST ELECTRODE, C. AN ELECTROLYTE SOLUTION IN MUTUAL CONTACT WITH AT LEAST A PART OF SAID ELECTRODES, SAID ELCTROLYTE INCLUDING CATIONS AND ANIONS THE LATTER OF WHICH ARE SELECTED FROM THE GROUP OF CHLORIDE, BROMIDE AND IODIDE ANIONS, AND SAID SOLUTION INCLUDING A BUFFER, D. AN OXYGEN PERMEABLE, ION IMPERMEABLE MEMBRANE INTERFACED ON ONE SIDE WITH SAID ELECTROLYTE AND HAVING ITS

Claim 3

The sensor defined in claim 1 wherein: a. said reference electrode is more particularly a silver-silver chloride electrode.

Claim 4

The sensor defined in claim 1 wherein: a. said buffer has a pH range between pH5 and pH8.

Claim 5

The sensor defined in claim 1 wherein: a. said first electrode is particularly tungsten and the pH of said buffer is at least pH5.

Claim 6

The sensor defined in claim 1 wherein: a. said electrolyte is comprised of cations selected from the group of sodium and potassium cations.

Claim 7

The sensor defined in claim 5 wherein: a. said electrolyte has a predetermined molarity for making it isoosmotic with said sample.

Claim 8

The sensor defined in claim 5 wherein: a. said electrolyte solution has a molarity of about 0.15M for making it substantially isoosmotic with said sample which is characterized as blood.

Claim 9

A potentiometric sensor for measUring the partial pressure of oxygen in blood, comprising: a. a first measuring electrode whose potential depends on oxygen concentration in a medium contacting it and is comprised of a thin wire selected from the class of tungsten, molybdenum and tantalum and alloys thereof, b. an insulating layer surrounding at least a portion of said wire and leaving a tip portion exposed, c. a silver-silver chloride reference electrode separated from said tip portion by said insulating layer, d. an electrolyte solution including a buffer in mutual contact with said tip and said reference electrode, and e. an oxygen permeable, ion impermeable membrane encapsulating said electrolyte.

Claim 10

A potentiometric sensor for measUring the partial pressure of oxygen in blood, comprising: a. a first measuring electrode whose potential depends on oxygen concentration in a medium contacting it and is comprised of a thin wire selected from the class of tungsten, molybdenum and tantalum and alloys thereof, b. an insulating layer surrounding at least a portion of said wire and leaving a tip portion exposed, c. a silver-silver chloride reference electrode separated from said tip portion by said insulating layer, d. an electrolyte solution including a buffer in mutual contact with said tip and said reference electrode, and e. an oxygen permeable, ion impermeable membrane encapsulating said electrolyte.

Claim 11

The sensor set forth in claim 8 wherein: a. said electrolyte comprises a salt selected from the group of sodium chloride and potassium chloride.

Claim 12

The sensor defined in claim 9 wherein: a. said buffer has a pH of at least 5.

Claim 13

The sensor set forth in claim 10 wherein: a. said electrolyte is a substantially 0.15 Molar solution of said selected salt.

Claim 14

The sensor defined in claim 9 wherein: a. the molarity of said salt is substantially 0.15 Molar.

Claim 15

A sensor for determining the partial pressure of oxygen in a fluid sample comprising: a. a first electrode whose potential depends on oxygen concentration in a medium contacting it, characterized as being made of a metal which reduces oxygen coming in contact therewith and which simultaneously corrodes in an electrolyte solution to thereby acquire a potential dependent on the rates of reduction and corrosion, said metal being selected from the group consisting of tungsten, molybdenum and tantalum and alloys thereof b. a reference electrode spaced from said first electrode, c. an electrolyte solution in mutual contact with said first and reference electrodes and serving to intervene between said electrodes and said sample, and d. an oxygen permeable, ion impermeable membrane encapsulating said electrolyte.

Claim 16

A sensor for determining the partial pressure of oxygen in a fluid sample comprising: a. a first electrode whose potential depends on oxygen concentration in a medium contacting it, characterized as being made of a metal which reduces oxygen coming in contact therewith and which simultaneously corrodes in an electrolyte solution to thereby acquire a potential dependent on the rates of reduction and corrosion, said metal being selected from the group consisting of tungsten, molybdenum and tantalum and alloys thereof b. a reference electrode spaced from said first electrode, c. an electrolyte solution in mutual contact with said first and reference electrodes and serving to intervene between said electrodes and said sample, and d. an oxygen permeable, ion impermeable membrane encapsulating said electrolyte.

Claim 17

The invention set forth in claim 13 wherein: a. said electrolyte solution includes anions selected from the group of chloride, bromide and iodide anions, and b. said reference electrode is a silver-silver halide electrode, the halide being the same as said selected anion.

Claim 18

The invention set forth in claim 14 wherein: a. said electrolyte solution contains a buffer that establishes the pH of said solution at substantially 5.