System, method, and probe for monitoring pH levels of a sample medium

• US 7,972,495 B1
• Filed: 01/31/2007
• Issued: 07/05/2011
• Est. Priority Date: 05/07/2003
• Status: Expired due to Fees

• Current Assignee: Millar Instruments
• Original Assignee: Millar Instruments
• Inventors: Millar, Huntly D., Pauly, Robert L.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US11/669,289
• Time in Patent Office: 1,616 Days
• Field of Search: 204/433, 204/435, 205/787.5
• US Class Current: 205/787.5
• CPC Class Codes: G01N 27/333 Ion-selective electrodes or membranes glass electrodes G01N27/36
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A system for monitoring a pH level of a sample medium is disclosed herein as including a pH probe having a pH-sensitive electrode, a reference electrode and a temperature electrode arranged within a housing of the pH probe. The probe housing generally includes a flexible inner tube and a flexible outer tube, the inner tube being concentrically arranged within the outer tube. Preferably, a size of the probe housing minimizes the amount of trauma introduced by insertion of the pH probe into physiological tissues, muscles or fluids. The system also includes a processing means, which is coupled to the pH probe for determining the pH of the sample medium. A method of forming a pH-sensitive electrode, a method of manufacturing a pH probe, and a method for using a pH probe are also disclosed herein.

Claims

1. A method for manufacturing a pH probe, the method comprising:

providing a probe housing comprising an inner tube concentrically arranged within an outer tube of the probe housing;

forming one or more diffusion windows within a sidewall of the outer tube proximate to a first end of the outer tube;

arranging a plurality of electrodes each having a sensing portion and a conductive portion within the probe housing, wherein said arranging ensures that a sensing portion of one of the plurality of electrodes protrudes from a first end of the probe housing and a conductive portion of each of the plurality of electrodes protrudes from a second end of the probe housing, wherein at least one of the plurality of electrodes comprises a pH-sensitive electrode having a sensing portion with a smooth hemispherical tip formed by dipping one end of an antimony rod fragment into a molten antimony solution and allowing the sensing portion to harden while pointing in a downward direction;

sealing the first and second ends of the probe housing with a sealant material, such that the protruding portions of the plurality of electrodes remain exposed; and

inserting an electrolytic solution into a space bounded by the outer tube, the inner tube and the sealant material, wherein said inserting comprises filling an entirety of the space with the electrolytic solution during manufacturing of the probe.

2. The method as recited in claim 1, wherein said arranging a plurality of electrodes comprises arranging the one of the plurality of electrodes within the inner tube, and arranging the remaining ones of the plurality of electrodes within a space between the outer tube and the inner tube.

3. The method as recited in claim 1, wherein said inserting an electrolytic solution comprises creating a vacuum within the space before filling the entirety of the space with the electrolytic solution via the one or more diffusion windows.

4. The method as recited in claim 1, wherein said inserting an electrolytic solution comprises filling the entirety of the space by forcefully injecting the electrolytic solution through the one or more diffusion windows.

5. The method as recited in claim 1, further comprising sealing the one or more diffusion windows by placing a protective cap around the first end of the probe housing, wherein said sealing prevents evaporation and/or crystallization of the electrolytic solution.

6. The method as recited in claim 1, wherein a method for forming the pH-sensitive electrode comprises:

drawing a molten solution comprising some amount of antimony into a disposable tube;

cooling the molten solution to form an antimony rod;

detaching a fragment of the antimony rod after removing the antimony rod from the disposable tube; and

forming the sensing portion of the pH-sensitive electrode by dipping the one end of the antimony rod fragment into the molten solution and allowing the sensing portion to harden while the pH-sensitive electrode is secured in a downward-pointing direction.