Method for detecting the presence or absence of a gas bubble in an aqueous liquid

• US 20060042963A1
• Filed: 08/31/2005
• Published: 03/02/2006
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Kaltenbeck, Heinz, Grubler, Robert, Landschutzer, Egon
• Granted Patent: US 7,807,041 B2
• Time in Patent Office: Days
• US Class Current: 205/775
• CPC Class Codes: G01N 27/404 Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid , e.g. Clark-type oxygen sensors
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence

Abstract

A method for detecting the presence or absence of a gas bubble in an aqueous liquid is provided comprising providing an amperometric sensor positioned within a measuring chamber, wherein the amperometric sensor is configured to determine the concentration of a gaseous component dissolved in a liquid, the amperometric sensor comprising a sensitive region; positioning the liquid in the measuring chamber; taking at least one first measurement value of the gaseous component from a first portion of the liquid after a predetermined response time, the first portion located in the sensitive region of the sensor; moving the liquid along in the measuring chamber, such that a second portion of the liquid, which had previously been located outside the sensitive region of the amperometric sensor, is positioned in the sensitive region; taking at least one second measurement value of the gaseous component from the second portion of the liquid; and detecting the presence or absence of a gas bubble by comparing the first and second measured values. The gas bubble, if present, is in at least partial contact with the sensitive region of the amperometric sensor.

Claims

1. A method for detecting the presence or absence of a gas bubble in an aqueous liquid, comprising:

providing an amperometric sensor positioned within a measuring chamber, wherein said amperometric sensor is configured to determine the concentration of a gaseous component dissolved in a liquid, said amperometric sensor comprising a sensitive region;

positioning said liquid in said measuring chamber;

taking at least one first measurement value of said gaseous component from a first portion of said liquid after a predetermined response time, said first portion located in said sensitive region of said sensor;

moving said liquid along in said measuring chamber, such that a second portion of said liquid, which had previously been located outside said sensitive region of said amperometric sensor, is positioned in said sensitive region;

taking at least one second measurement value of said gaseous component from said second portion of said liquid; and

detecting the presence or absence of a gas bubble by comparing said first and second measured values.

2. The method of claim 1, wherein said gas bubble is in at least partial contact with said sensitive region of said amperometric sensor.

3. The method of claim 1, wherein said liquid is inferred to be free of bubbles in said sensitive region of said amperometric sensor, if said second measured value is higher by a predetermined amount than said first measured value.

4. The method of claim 1 further comprising moving said second portion of said liquid to said sensitive region of said sensor in a measuring chamber with open inlet and outlet without significant change in pressure.

5. The method of claim 4, wherein said liquid is moved by a pumping or suction device.

6. The method of claim 1, wherein said gas bubble comprises air.

7. The method of claim 1, wherein said amperometric sensor is a gas sensor.

8. The method of claim 7, wherein said gas sensor is an O₂ sensor.

9. The method of claim 1, wherein said aqueous liquid comprises a fluid selected from calibrating fluid, control fluid or sample fluid.

10. The method of claim 9, wherein said sample fluid is a biological fluid.

11. The method of claim 10, wherein said biological fluid is blood.