Calibration card for oxygen optical sensors

• US 8,429,949 B2
• Filed: 11/03/2009
• Issued: 04/30/2013
• Est. Priority Date: 11/07/2008
• Status: Active Grant

• Current Assignee: MOCON, Inc. (Ametek Incorporated)
• Original Assignee: MOCON, Inc. (Ametek Incorporated)
• Inventors: Mayer, Daniel W.
• Primary Examiner(s): Raevis, Robert R
• Application Number:
  US13/128,040
• Publication Number:
  US 20110209520A1
• Time in Patent Office: 1,274 Days
• Field of Search: None
• US Class Current: 73/1.03
• CPC Class Codes: G01N 2021/6441 with two or more labels
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/278 Constitution of standards
• 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 436/100833 Simulative of a gaseous composition
• CPC Class Codes: Y10T 436/20 Oxygen containing
• CPC Class Codes: Y10T 436/207497 Molecular oxygen
• CPC Class Codes: Y10T 436/25875 Gaseous sample or with change of physical state

Abstract

A calibration card 10 and method of using the card 10 to calibrate an optical sensor. The card 10 comprises (i) a first mass of an oxygen sensitive fluorophore 41 configured and arranged for limiting exposure of the first mass of oxygen sensitive fluorophore 41 to near zero % oxygen, and (ii) a second mass of an oxygen sensitive fluorophore 42 configured and arranged for exposing the second mass of fluorophore 42 to an environmental concentration of oxygen.

Claims

1. A calibration card for use in calibrating an optical sensor, comprising a unitary structure bearing (i) a first mass of an oxygen sensitive fluorophore configured and arranged for limiting exposure of the first mass of oxygen sensitive fluorophore to near zero % oxygen, and (ii) a second mass of an oxygen sensitive fluorophore configured and arranged for exposing the second mass of fluorophore to an environmental concentration of oxygen.

2. The calibration card of claim 1 wherein the first mass of oxygen sensitive fluorophore is isolated from the environment and in fluid communication with an oxygen scavenging material effective for scavenging oxygen from the first mass of fluorophore.

3. The calibration card of claim 1, wherein the card has a length of about 4 to 20 cm, a width of about 4 to 20 cm, and a thickness of less than 1 cm.

4. The calibration card of claim 2, wherein the card has a length of about 6 to 10 cm, a width of about 4 to 8 cm, and a thickness of less than 3 mm.

5. The calibration card of claims 1 or 2, wherein the fluorophore in both the first and second masses of fluorophore are the same.

6. The calibration card of claims 1 or 2, wherein the first and second masses of fluorophore are sandwiched between an oxygen barrier support layer and an oxygen barrier transparent cover layer.

7. The calibration card of claim 6, wherein the transparent cover layer is a transparent layer of polyethylene terephthalate.

8. The calibration card of claim 2, wherein the oxygen scavenging material is activated by exposure to ultraviolet light.

9. The calibration card of claim 8, wherein the oxygen scavenging material is incorporated into a film.

10. The calibration card of claims 1 or 2, wherein the card contains first indicia tagging the first mass of fluorophore as fluorophore exposed to limited oxygen, and second indicia tagging the second mass of fluorophore as fluorophore exposed to an environmental concentration of oxygen.

11. The calibration card of claim 10, wherein the first indicia comprises at least the designation 0% and the second indicia comprises at least the designation 21%.

12. The calibration card of claim 6, wherein the second mass of fluorophore is in fluid communication with the environment via at least one channel through the support layer.

13. A method of calibrating an optical oxygen sensor having a calibration mode, comprising the steps of:

(A) obtaining a calibration card having at least (i) a first mass of an oxygen sensitive fluorophore configured and arranged for limiting exposure of the first mass of oxygen sensitive fluorophore to oxygen, whereby the oxygen concentration to which the first mass of oxygen sensitive fluorophore is exposed is a known lower value, and (ii) a second mass of an oxygen sensitive fluorophore in fluid communication with the environment for exposing the second mass of oxygen sensitive fluorophore to an environmental concentration of oxygen, whereby the oxygen concentration to which the second mass of oxygen sensitive fluorophore is exposed is a known higher value, (B) setting the optical sensor to calibration mode, and (C) sequentially taking an oxygen concentration reading from each of the masses of oxygen sensitive fluorophore such that the oxygen concentration readings are correlated with the lower and higher values to which the mass of oxygen sensitive fluorophore is exposed.

15. The method of claims 13 or 14, where step (C) comprises at least the step of taking an oxygen concentration reading from each of the masses of oxygen sensitive fluorophore in a predetermined sequence.

16. The method of claims 13 or 14, wherein step (C) comprises at least the steps of:

(1) sensing the oxygen concentration to which one of the masses of oxygen sensitive fluorophore is exposed using the optical sensor in calibration mode, (2) providing the optical sensor with data indicating which of the masses of oxygen sensitive fluorophore on the calibration card was sensed, and (3) sensing the oxygen concentration to which the other mass of oxygen sensitive fluorophore is exposed using the optical sensor in calibration mode.

17. The method of claims 13 or 14, wherein step (C) comprises at least the steps of:

(1) sensing the oxygen concentration to which one of the masses of oxygen sensitive fluorophore is exposed using the optical sensor in calibration mode, (2) providing the optical sensor with data indicating the known oxygen concentration to which the one mass of oxygen sensitive fluorophore is exposed, (3) sensing the oxygen concentration to which the other mass of oxygen sensitive fluorophore is exposed using the optical sensor in calibration mode, and (4) providing the optical sensor with data indicating the known oxygen concentration to which the other mass of oxygen sensitive fluorophore is exposed.

18. The method of claim 13, wherein the card has a length of about 6 to 10 cm, a width of about 4 to 8 cm, and a thickness of less than 3 mm.

19. The method of claims 13 or 14, wherein the first and second masses of oxygen sensitive fluorophore are sandwiched between an oxygen barrier support layer and an oxygen barrier transparent cover layer.

21. The method of claims 13 or 14, wherein the card contains first indicia tagging the first mass of oxygen sensitive fluorophore as the mass exposed to no oxygen, and second indicia tagging the second mass of oxygen sensitive fluorophore as the mass exposed to an environmental concentration of oxygen.

22. The method of claim 21 wherein the first indicia comprises at least the numerical value 0% and the second indicia comprises at least the numerical value 21%.

14. A method of calibrating an optical oxygen sensor having a calibration mode, comprising the steps of:

(A) obtaining a calibration card having at least (i) a first mass of an oxygen sensitive fluorophore isolated from the environment and in fluid communication with an oxygen scavenging material effective for scavenging oxygen from the first mass of oxygen sensitive fluorophore, whereby the oxygen concentration to which the first mass of oxygen sensitive fluorophore is exposed is a known lower value, and (ii) a second mass of an oxygen sensitive fluorophore in fluid communication with the environment for exposing the second mass of oxygen sensitive fluorophore to an environmental concentration of oxygen, whereby the oxygen concentration to which the second mass of oxygen sensitive fluorophore is exposed is a known higher value, (B) setting the optical sensor to calibration mode, and (C) sequentially taking an oxygen concentration reading from each of the masses of oxygen sensitive fluorophore such that the oxygen concentration readings are correlated with the lower and high values to which the mass of oxygen sensitive fluorophore is exposed.

20. The method of claim 14, wherein the oxygen scavenging material is activated by exposure to ultraviolet light prior to taking an oxygen concentration reading from the masses of oxygen sensitive fluorophore.