Microscale electrochemical cell and methods incorporating the cell

• US 20070170056A1
• Filed: 01/26/2006
• Published: 07/26/2007
• Est. Priority Date: 01/26/2006
• Status: Abandoned Application

• Current Assignee: AB Sciex LLC (Danaher Corporation)
• Original Assignee: AB Sciex LLC (Danaher Corporation)
• Inventors: Jiang, Guifeng, Arnold, Don, Hebert, Nicole
• Application Number:
  US11/341,221
• Publication Number:
  US 20070170056A1
• Time in Patent Office: Days
• US Class Current: 204/412
• CPC Class Codes: G01N 27/403 Cells and electrode assemblies

Abstract

An electrochemical cell for processing a sample fluid, has a body with a flow path, the flow path having an inlet and an outlet; a reference electrode in fluid communication with the flow path; a counter electrode in fluid communication with the flow path; a porous working electrode in fluid communication with the flow path, the working electrode having a working electrode material; an electrical connection for the working electrode in electrical contact with the working electrode; and a working electrode section in the flow path. The working electrode is positioned inside the working electrode section. The working electrode section has a volume of from about 1 pL to about 1 μL.

Claims

1. An electrochemical cell for processing a sample fluid, the cell comprising:

A monolithic body having a flow path, the flow path having an inlet and an outlet;

a reference electrode in fluid communication with the flow path;

a counter electrode in fluid communication with the flow path;

a porous working electrode in fluid communication with the flow path, the working electrode comprising a working electrode material;

an electrical connection for the working electrode in electrical contact with the working electrode; and

a working electrode section in the flow path, the working electrode being positioned inside the working electrode section; and

wherein the working electrode section has a volume of from about 1 pL to about 1 μ

L.

2. The cell of claim 1 wherein the cell further comprises a filling conduit in fluid communication with the working electrode section for placement of the working electrode material;

and

wherein the working electrode section is bounded by weirs, the weirs allowing passage of sample fluid and blocking passage of the working electrode material.

3. The cell of claim 2 wherein the body comprises fused silica.

4. The cell of claim 3 wherein the working electrode comprises particles having a diameter of from about 10 nm to about 100 μ

m.

5. The cell of claim 1 wherein the flow path has a volume of from about 1 nL to about 50 nL.

6. The cell of claim 1 wherein the reference electrode and the counter electrode further comprise non-reactive metal wire having a diameter of from about 5 μ

m to about 500 μ

m.

7. The cell of claim 6 wherein the reference electrode and the counter electrode comprise inert metal wire having a diameter of from about 25 μ

m to about 125 μ

m.

8. The cell of claim 1 wherein the reference electrode and the counter electrode comprise at least one of the group consisting of palladium, platinum and silver.

9. The cell of claim 8 wherein at least one of the reference electrode and the counter electrode comprise a porous polymeric coating.

10. The cell of claim 1 further comprising:

a second reference electrode in fluid communication with the flow path; and

a second counter electrode in fluid communication with the flow path.

11. The cell of claim 1 wherein the working electrode comprises at least one of carbon, copper, gold, palladium and platinum.

12. The cell of claim 1 wherein the working electrode comprises at least one of silver, indium tin oxide and tin oxide.

13. The cell of claim 1 wherein the flow path comprises an annular section around at least one of the counter electrode and the reference electrode.

20. An electrochemical detection system comprising:

a cell according to claim 1;

and

a light detector;

wherein the cell converts at least one of an analyte and a reagent to a luminescent species detectable by the light detector.

21. An electrochemical detection system comprising:

a cell according to claim 1;

and

a light source;

wherein the light source converts at least one of an analyte and a reagent to a species detectable by the cell.

14. An electrochemical detection system comprising:

a circuit board;

an electrochemical cell electrically coupled to the circuit board, the cell comprising;

a body having a flow path, the flow path having an inlet and an outlet;

a reference electrode in fluid communication with the flow path;

a counter electrode in fluid communication with the flow path;

a porous working electrode positioned in the flow path, the working electrode comprising a working electrode material;

an electrical connection for the working electrode in electrical contact with the working electrode; and

a working electrode section in the flow path, the working electrode being positioned inside the working electrode section;

wherein the working electrode section has a volume of from about 1 pL to about 1 μ

L;

a preamplifier electrically connected to the circuit board and the cell;

a connector electrically connected to the preamplifier; and

a housing surrounding the circuit board, the preamplifier and the connector.

15. The system of claim 14 further comprising:

a control and data acquisition system electrically connected to the connector;

a heater mounted to the housing and electrically connected to the control and data acquisition system; and

a sensor for sensing a housing temperature mounted to the housing and electrically connected to the control and data acquisition system;

wherein the control and data acquisition system controls the heater to heat the housing based upon the housing temperature sensed by the sensor.

16. The system of claim 14 further comprising a liquid chromatography column having an inlet and an outlet, the outlet of the liquid chromatography column being in fluid communication with the flow path inlet.

17. The system of claim 14 further comprising an interface to a mass spectrometer in fluid communication with the flow path outlet.

18. The system of claim 14 further comprising:

a second electrochemical cell, the outlet of the second cell being in fluid communication with the chromatography column inlet;

a sample injector in fluid communication with the inlet of the second cell; and

a solvent delivery system in fluid communication with the sample injector.

19. The system of claim 18 further comprising:

a solvent delivery system;

a second electrochemical cell in fluid communication with the solvent delivery system; and

a sample injector in fluid communication with the outlet of the second cell and the chromatography column inlet;

wherein the second cell is adapted to cleanse a solvent in the solvent delivery system.

26. A method for detecting samples from a sample fluid comprising the steps of:

selecting the electrochemical detection system of claim 14;

passing a solvent and the sample fluid through the liquid chromatography column; and

detecting the samples as the samples pass through the electrochemical cell.

27. A method for detecting samples from a sample fluid comprising the steps of:

selecting the electrochemical detection system of claim 18;

passing the sample fluid into the second electrochemical cell; and

using the second electrochemical cell as a microreactor for converting samples in the sample fluid.

28. A method for detecting samples from a sample fluid comprising the steps of:

selecting the electrochemical detection system of claim 18;

passing the sample fluid into the second electrochemical cell; and

using the second electrochemical cell to concentrate samples in the sample fluid.

22. An array of electrochemical cells comprising:

a monolithic body comprising silica and a flow path, the flow path having an inlet and an outlet;

a plurality of reference electrodes in fluid communication with the flow path;

a plurality of counter electrodes in fluid communication with the flow path;

a plurality of separate porous working electrodes positioned in the flow path; and

separate electrical connections for each of the working electrodes in electrical contact with the working electrodes.

23. The array of claim 22 comprising from about 2 to about 16 working electrodes.

24. An electrochemical detection system comprising:

first and second electrochemical cells, each cell further comprising;

a) a body having a flow path, the primary flow path having an inlet and an outlet;

b) a reference electrode in fluid communication with the flow path;

c) a counter electrode in fluid communication with the flow path;

d) a porous working electrode positioned in the flow path, the working electrode comprising a working electrode material; and

e) an electrical connection for the working electrode in electrical contact with the working electrode; and

f) a working electrode section in the flow path, the working electrode being positioned inside the working electrode section;

wherein the outlet of the first cell is in fluid communication with the inlet of the second cell; and

wherein each working electrode section has a volume of from about 1 pL to about 1 μ

L.

25. The system of claim 24 wherein the first cell has a first electric potential;

the second cell has a second electric potential; and

the first and second electric potentials are different.

29. A method for making an electrochemical cell comprising the steps of:

forming a monolithic body having a fluid manifold, the fluid manifold having a flow path, a working electrode section in the flow path, a filling conduit in communication with the working electrode section, and a plurality of secondary conduits in communication with the flow path;

packing a working electrode material into the working electrode section through the filling conduit to create a working electrode;

sealing the filling conduit with electrically non-reactive material;

mounting;

i) a reference electrode in a first of the secondary conduits;

ii) a counter electrode in a second of the secondary conduits; and

iii) an electrical connection to the working electrode in a third secondary conduit; and

sealing the secondary conduits with an electrically non-reactive material;

wherein the working electrode section has a volume of from about 1 pL to about 1 μ

L.

30. The method of claim 29 wherein the step of forming the body further comprising microfabricating weirs defining the working electrode section.

31. The method of claim 29 wherein the body is formed using photolithography.