Temperature stabilized fluid reference system

• US 6,060,319 A
• Filed: 06/25/1993
• Issued: 05/09/2000
• Est. Priority Date: 12/13/1991
• Status: Expired due to Term

• Current Assignee: Easydx Inc.
• Original Assignee: Diametrics Medical, Inc. (Allegro Biodiesel Corp.)
• Inventors: Morris, Russell L., Deetz, David W.
• Primary Examiner(s): TRAN, LIEN THUY
• Application Number:
  US08/083,680
• Time in Patent Office: 2,510 Days
• Field of Search: 422/62, 422/83, 436/8, 436/11, 436/9, 436/16, 436/55, 436/68
• US Class Current: 436/8
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: G01N 2496/70 Blood gas control solutios containing dissolved oxygen, bicarbonate and the like
• CPC Class Codes: G01N 33/0006 Calibrating gas analysers
• CPC Class Codes: G01N 33/96 involving blood or serum control standard
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
• CPC Class Codes: Y10T 436/102499 Blood gas standard or control
• CPC Class Codes: Y10T 436/106664 Blood serum or blood plasma standard or control

Abstract

A method and system for controlling the concentration of one or more gaseous species of interest in a fluid reference medium throughout a range of temperatures in which a temperature related, dominant independent source of the gaseous species of interest is used to control the partial pressure of one or more gaseous species of interest contained in the reference medium in a manner such that the concentration of the gaseous species of interest in the reference medium is controlled as a predetermined, normally generally linear, function of temperature, f(T), over the temperature range. The source of the one or more gaseous species of interest is a separate reservoir containing an amount of a formulated temperature sensitive source of the one or more gaseous species of interest. The reference medium and the reservoir are contained in separate liquid-tight, gas-permeable enclosures contained in a common substantially gas-tight enclosure.

Claims

1. A method of controlling a concentration of a gaseous species of interest in a reference medium as a predetermined function of temperature throughout a selected temperature range comprising the steps of:

(a) isolating the reference medium containing the gaseous species of interest in a gas-permeable reference enclosure;

(b) providing a separate reservoir source of the gaseous species of interest outside but in communication with the gas permeable reference enclosure, wherein the reservoir source of gaseous species of interest is formulated to control the concentration of the gaseous species of interest in the reference medium according to a desired function of temperature, f(T), over the selected temperature range;

(c) enclosing the reference medium and reservoir source in a substantially gas-tight hollow common enclosure surrounded by a gas phase that forms a common atmosphere; and

(d) enabling the reservoir source to compensate for temperature fluctuations within the selected temperature range by controlling the partial pressure of the gaseous species of interest in the common enclosure as a function of temperature such that the concentration of the gaseous species of interest in the reference medium varies as a function of temperature according to the f(T) over the selected temperature range.

2. The method as in claim 1 wherein the species of interest is carbon dioxide (CO₂).

4. The method as in claim 1 wherein said reference medium varies as a generally linear function of temperature according to said f(T).

3. A system for controlling a concentration of one or more gaseous species of interest in a reference medium as a predetermined function of temperature in a temperature range comprising:

(a) a liquid-tight gas-permeable reference enclosure for isolating the reference medium containing the gaseous species of interest;

(b) a separate reservoir source of the gaseous species of interest outside but in communication with the gas permeable reference enclosure, wherein the reservoir source of gaseous species of interest is formulated to control the concentration of the gaseous species of interest in the reference medium according to a desired function of temperature, f(T), over the selected temperature range;

(c) common enclosure means for enclosing the reference medium and reservoir source in a substantially gas-tight hollow structure surrounded by a gas phase that forms a common atmosphere; and

(d) wherein the reservoir source compensates for temperature fluctuations within the selected temperature range in the common enclosure by controlling the partial pressure of the gaseous species of interest in the common enclosure means as a function of temperature such that the concentration of the gaseous species of interest in the reference medium varies as a function of temperature according to the f(T) over the selected temperature range.

5. The apparatus of the system of claim 3 wherein the reference medium is caused to vary in a substantially linear manner as a function of temperature according to said f(T).