Apparatus and method for analytical determinations using amperometric techniques

• US 20040182722A1
• Filed: 03/20/2003
• Published: 09/23/2004
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: Easydx Inc.
• Original Assignee: Diametrics Medical, Inc. (Allegro Biodiesel Corp.)
• Inventors: Blomberg, Scott Everett, Sin, Kee Van, Kurkowski, James Donald
• Granted Patent: US 8,323,475 B2
• Time in Patent Office: Days
• US Class Current: 205/775
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• 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 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3

Abstract

A system for operating at least first and second amperometric sensors includes a cartridge and a control device. The cartridge includes a first amperometric sensor and a second amperometric sensor. The first amperometric sensor is in fluid flow communication with a liquid sample inlet and includes a first electrode. The second amperometric sensor is in fluid flow communication with a liquid sample and includes a second electrode. The control device sets the first and second electrodes to about the same potential such that the first and second amperometric sensors can be operated simultaneously.

Claims

1. A system for operating at least first and a second amperometric sensors, the system comprising:

(a) a cartridge including;

(i) a first amperometric sensor in fluid flow communication with a liquid sample inlet and including a first electrode;

(ii) a second amperometric sensor in fluid flow communication with the liquid sample inlet and including a second electrode; and

(b) a control device for setting the first and second electrodes to about the same potential such that the first and second amperometric sensors can be operated simultaneously.

2. A system according to claim 1 wherein:

(a) the first amperometric sensor is a three electrode sensor; and

(b) the second amperometric sensor is a three electrode sensor.

3. A system according to claim 1 wherein:

(a) the first electrode is a first auxiliary electrode; and

(b) the second electrode is a second auxiliary electrode.

4. A system according to claim 1 wherein:

(a) the first amperometric sensor is positioned no more than 2 cm from the second amperometric sensor.

5. A system according to claim 1 wherein:

(a) the first amperometric sensor is an O₂ sensor.

6. A system according to claim 1 wherein:

(a) the second amperometric sensor is a glucose sensor.

7. A system according to claim 1 wherein:

(a) the cartridge has a perimeter area of no greater than 80 sq. cm.

8. A system according to claim 1 wherein:

(a) the first and second amperometric sensor are positioned in a flow channel segment having a volume of not greater than 0.250 ml.

9. A system according to claim 1 further including:

(a) at least one ion selective electrode positioned in the flow channel segment between the first and second amperometric sensors.

10. A system according to claim 1 wherein the cartridge further includes:

(a) a third amperometric sensor in fluid flow communication with the liquid sample inlet and including a third electrode.

11. A system according to claim 1 wherein the cartridge and control system are portable.

12. A system according to claim 1 wherein the first electrode is covered by a first membrane having a relatively high impedance, and the second electrode is covered by a second membrane having a relatively high impedance.

13. A method of simultaneously operating at least first and second amperometric sensors, the method comprising:

(a) providing a first amperometric sensor in fluid flow communication with a liquid sample inlet and including a first electrode;

(b) providing a second amperometric sensor in fluid flow communication with the liquid sample inlet and including a second electrode; and

(c) setting the first and second electrodes to about the same potential such that the first and second amperometric sensors can be operated simultaneously.

14. A method according to claim 13 wherein:

(a) providing a first amperometric sensor includes providing a first amperometric sensor having three electrodes; and

(b) providing a second amperometric sensor includes providing a second amperometric sensor having three electrodes.

15. A method according to claim 13 wherein:

(a) providing a first amperometric sensor includes providing a first amperometric sensor in fluid flow communication with a liquid sample inlet and including a first auxiliary electrode; and

(b) providing a second amperometric sensor includes providing a second amperometric sensor in fluid flow communication with a liquid sample inlet and including a second auxiliary electrode.

16. A method according to claim 13 wherein:

(a) providing a second amperometric sensor includes providing a second amperometric sensor positioned no more than 2 cm from the first amperometric sensor.

17. A method according to claim 13 wherein:

(a) providing a first amperometric sensor includes providing an O₂ sensor.

18. A method according to claim 13 wherein:

(a) providing a second amperometric sensor includes providing a glucose sensor.

19. A method according to claim 13 wherein:

(a) providing first and second amperometric sensor includes providing the first and second amperometric sensor positioned in a flow channel segment having a volume of not greater than 0.250 ml.

20. A method according to claim 13 further including:

(a) providing at least one ion selective electrode positioned in a flow channel segment between the first and second amperometric sensors.

21. A method according to claim 13 further including:

(a) providing a third amperometric sensor in fluid flow communication with the liquid sample inlet and including a third electrode.

22. A method of operating at least first and second amperometric sensors, the method comprising:

(a) setting a goal fluid potential value;

(b) reading a first electrode potential within the first amperometric sensor;

(c) reading a second electrode potential within the second amperometric sensor; and

(d) calculating an adjustment to the first and second electrode potentials, such that the first and second amperometric sensors can be operated simultaneously.

23. A method according to claim 22 wherein:

(a) reading a first electrode potential includes reading a first auxiliary potential; and

(b) reading as second electrode potential includes reading a second auxiliary potential.

24. A method according to claim 22 wherein:

(a) reading a first electrode potential includes reading a first working potential; and

(b) reading as second electrode potential includes reading a second working potential.

25. A method according to claim 22 wherein:

(a) reading a first electrode potential includes reading a first reference potential; and

(b) reading as second electrode potential includes reading a second reference potential.

26. A method according to claim 22 further including:

(a) adjusting the first and second electrode potentials such that the first and second amperometric sensors can be operated simultaneously.

27. A method according to claim 22 further including:

(a) reading a third electrode potential within a third amperometric sensor.

28. A method according to claim 27 further including:

(a) calculating an adjustment to the third electrode potential, such that the first, second, and third amperometric sensors can be operated simultaneously.

29. A method according to claim 28 further including:

(a) adjusting the first, second, and third electrode potentials such that the first, second, and third amperometric sensors can be operated simultaneously.

30. A cartridge for analyzing at least first and second analytes, the cartridge comprising:

(a) a first amperometric sensor in fluid flow communication with a liquid sample inlet and including a first electrode and a first sensor membrane positioned between the first electrode and a fluid flow channel; and

(b) a second amperometric sensor in fluid flow communication with the liquid sample inlet and including a second electrode and a second sensor membrane positioned between the second electrode and the fluid flow channel;

(c) wherein the first and second sensor membranes are configured to have a high impedance such that the first and second amperometric sensors can be simultaneously operated.

31. A cartridge according to claim 30, wherein the impedance of the first and second membranes is between one mega ohm and one hundred mega ohms.

32. A cartridge according to claim 30, wherein the first sensor membrane comprises silicone.

33. A cartridge according to claim 30, wherein:

(a) the first amperometric sensor is a three electrode sensor; and

(b) the second amperometric sensor is a three electrode sensor.

34. A cartridge according to claim 33 wherein:

(a) the first amperometric sensor is an O₂ sensor.

35. A cartridge according to claim 33 wherein:

(a) the second amperometric sensor is a glucose sensor.

36. A cartridge according to claim 30 further including:

(a) at least one ion selective electrode positioned in the flow channel segment between the first and second amperometric sensors.

37. A cartridge according to claim 30 wherein the cartridge further includes:

(a) a third amperometric sensor in fluid flow communication with the liquid sample inlet and including a third electrode.