FLUID SAMPLE ANALYZING APPARATUS

• US 3,661,010 A
• Filed: 04/07/1970
• Issued: 05/09/1972
• Est. Priority Date: 04/07/1970
• Status: Expired due to Term

• Current Assignee: Fisher Scientific Co. (Thermo Fisher Scientific Incorporated)
• Original Assignee: Robert T. Neuwelt
• Inventors: Neuwelt, Robert T.
• Primary Examiner(s): Prince, Louis R.
• Assistant Examiner(s): Roskos, Joseph W.
• Application Number:
  US05/027,193
• Time in Patent Office: 763 Days
• Field of Search: 73/53,61,19,23 128/2E,2.1E,2.5D
• US Class Current: 73/61.72
• 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

Abstract

In a method of analyzing a fluid sample employing an electrochemical sensor that has a selectively permeable membrane disposed in the sample chamber, sample fluid to be analyzed is introduced into the sample chamber at a first flow rate, and flow of the sample fluid across the membrane in the sample chamber is continued at a reduced rate for a length of time greater than that required to fill the sample chamber at the first flow rate.

Claims

1. Fluid sample analyzing apparatus comprising a sample chamber having an inlet and an outlet, a constituent sensor in communication with said sample chamber, said constituent sensor including a sensing surface and a selectively permeable membrane disposed between said sensing surface and the fluid sample in said chamber, means to introduce a fluid sample into said chamber for analysis at a first flow rate, and means to continue flow of the sample fluid across said membrane at an exponentially decreasing rate for a length of time greater than that required to fill said sample chamber at said first flow rate.

2. Fluid sample analyzing apparatus comprising a sample chamber having an inlet and an outlet, a constituent sensor in communication with said sample chamber, a small diameter, relatively rigid, fluid resistor conduit coupled to said chamber inlet, a fluid capacitor conduit of larger diameter and greater flexibility than said resistor conduit connected to said chamber outlet, a suction pump connected to the outlet of said capacitor conduit, and a control valve interposed between said pump and said capacitor conduit for controlling the flow of fluid through said resistor conduit, said sample chamber, and said capacitor conduit, said capacitor conduit having sufficient flexibility to produce continued movement of fluid sample through said chamber after said valve is closed.

3. The apparatus as claimed in claim 2 wherein said constituent sensor includes a sensing surface and a selectively permeable membrane disposed between said sensing surface and the fluid sample in said chamber.

4. The apparatus as claimed in claim 2 wherein said sample chamber has a volume of less than 1 milliliter, two constituent sensors are disposed in communication with said sample chamber, each said constituent sensor including a sensing surface and a selectively permeable membrane disposed between said sensing surface and the fluid sample in said chamber.

5. The apparatus as claimed in claim 4 wherein one said constituent sensor is a Po2 electrode assembly and the other constituent sensor is a Pco2 electrode assembly.