Aqueous ferrioxalate compositions useful as calibrants

• US 5,070,023 A
• Filed: 02/03/1989
• Issued: 12/03/1991
• Est. Priority Date: 10/14/1988
• Status: Expired due to Fees

• Current Assignee: Il Holding SpA (Werfen SA)
• Original Assignee: Fisher Scientific Co. (Thermo Fisher Scientific Incorporated)
• Inventors: Calabrese, Gary S.
• Primary Examiner(s): Lacey, David L.
• Assistant Examiner(s): Chan, William K. Y.
• Application Number:
  US07/305,567
• Time in Patent Office: 1,033 Days
• Field of Search: 435/8-19, 423/594, 423/632, 423/415 R, 423/415 P, 252/408.1
• US Class Current: 436/8
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence
• 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 436/109163 Inorganic standards or controls

Abstract

Aqueous acidic ferrioxalate compositions are disclosed for use as calibrants of pCO2 and of PO2 after photodecomposition. Compositions with high iron(III) to oxalate molar ratios (e.g., 5:1 to 100:1 with 0.3 to 15 millimolar oxalate) produce carbon dioxide on exposure without oxygen consumption. Compositions with low iron(III) to oxalate ratios (e.g., 1:100 to 1:2000) with 0.1 to 5 millimolar iron(III) produce carbon dioxide on exposure with concurrent oxygen consumption. Use of the two types of compositions enables calibration values to be established with varying pCO2 values and with, respectively, high and low pO2 values.

Claims

1. An aqueous solution having a pH of 0 to 5 and comprising 0.3 to 15 millimoles per liter oxalate and 1.5 to 200 millimoles per liter of iron (III);

the molar ratio of iron (III) to oxalate being 5;

1 to 100;

1.

2. The aqueous solution of claim 1 wherein the pH is 0 to 2.

3. The aqueous solution of claim 2 wherein the molar ratio of iron (III) to oxalate is 10:

1 to 50;

1.

4. The aqueous solution of claim 3 wherein the oxalate concentration is 0.6 to 1.5 millimoles per liter and the iron (III) concentration is 6 to 75 millimoles per liter.

5. The aqueous solution of claim 2 wherein the oxalate concentration is 0.6 to 1.5 millimoles per liter.

6. An aqueous solution having a pH of 0 to 5 and comprising 0.2 to 5 millimoles per liter iron (III) and at least 1 millimole per liter oxalate;

the molar ratio of oxalate to iron (III) being at least about 5;

1.

7. The aqueous solution of claim 6 having a pH of 0 to 2.

8. The aqueous solution of claim 7 having 0.2 to 0.5 millimoles per liter iron (III).

9. The aqueous solution of claim 8 wherein the molar ratio of oxalate to iron (III) is at least about 100:

1.

10. The aqueous solution of claim 8 wherein the molar ratio of oxalate to iron (III) is about 100:

1 to about 2000;

1.

11. The aqueous solution of claim 10 having 0.20 to 0.25 millimoles per liter iron (III).

12. The aqueous solution of claim 11 having a pH of 1.0 to 1.5.

13. The aqueous solution of claim 8 wherein the molar ratio of oxalate to iron (III) is about 300:

1 to about 1000;

1.

14. An aqueous solution having a pH of 0 to 5 and comprising 0.1 to 5 millimoles per liter iron (III) and at least 10 millimoles per liter oxalate;

the molar ratio of oxalate to iron (III) being at least about 100;

1.

15. The aqueous solution of claim 14 having a pH of 0 to 2.

16. The aqueous solution of claim 15 having 0.1 to 0.5 millimoles per liter iron (III).

17. The aqueous solution of claim 16 wherein the molar ratio of oxalate to iron (III) is about 100:

1 to about 2000;

1.

18. The aqueous solution of claim 16 wherein the molar ratio of oxalate to iron (III) is about 300:

1 to about 1000;

1.

19. The aqueous solution of claim 16 having a pH of 1.0 to 1.5.