Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

Patent metadata

Field	Value
Publication number	US-9274059-B2
Application number	US-201314050144-A
Country	US
Kind code	B2
Filing date	Oct 9, 2013
Priority date	Mar 14, 2011
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

First claim

What is claimed is:

1. An electrochemical device for combined electrochemical analysis and chemical imaging of analytes at an electrode-liquid sample interface in-situ under vacuum, comprising:
an analytical instrument producing one or more probe beams;
an electrochemical microfluidic flow chamber that defines a liquid flow path through the flow chamber, the flow chamber includes a support membrane with at least one detection aperture configured to expose a surface of a liquid sample containing one or more analytes to one or more probe beams delivered from analytical instrument when the liquid sample is introduced past the at least one detection aperture under vacuum, the one or more probe beams when delivered through the at least one detection aperture determines the one or more analytes at the surface of the liquid sample providing chemical imaging thereof;
a working electrode configured to apply a selected potential into the liquid sample between the working electrode and a reference electrode that drives reactions of the one or more analytes in the liquid sample as a function of time, space, and/or potential; and
a counter electrode configured to measure electrical current stemming from reactions involving the one or more analytes to provide electrochemical analysis and chemical imaging of the analytes in the liquid sample at the surface of the working electrode-sample interface in-situ.

2. The electrochemical device of claim 1 , wherein the electrochemical device provides simultaneous electrochemical analysis and chemical imaging or individual electrochemical analysis and chemical imaging analyses of a surface of the liquid sample at a selected depth or a selected layer measured at the working electrode-sample interface.

3. The electrochemical device of claim 1 , further including a workstation disposed external to the electrochemical device configured to deliver the potential between the working electrode and reference electrode and to measure the current between the working electrode and the counter electrode.

4. The electrochemical device of claim 1 , wherein the electrodes have a form selected from wires, thin films, and sputter-deposited thin films comprising metals, metal oxides, carbon, graphene, and combinations thereof.

5. The electrochemical device of claim 1 , wherein the working electrode and the counter electrode are integrated with a reference electrode on a single substrate.

6. The electrochemical device of claim 1 , wherein the counter electrode and the reference electrode are disposed on a substrate different from the substrate containing the working electrode.

7. The electrochemical device of claim 1 , wherein the working electrode is disposed above the flow channel beneath the detection aperture and the counter electrode and the reference electrode are disposed below the flow channel in the electrochemical flow chamber.

8. The electrochemical device of claim 1 , wherein the support membrane is composed of a material selected from: silicon nitride (SiN), silicon dioxide (SiO 2 ), or combinations thereof.

9. The electrochemical device of claim 1 , wherein the electrochemical chamber includes one or more inlets and one or more outlets that deliver the liquid sample to and from the electrochemical chamber, respectively.

10. The electrochemical device of claim 9 , wherein the inlets and the outlets include one or more branches.

11. The electrochemical device of claim 1 , wherein the electrochemical chamber includes a flow channel with a depth in the range from about 0.1 μm to about 1000 μm.

12. The electrochemical device of claim 1 , wherein the electrochemical flow chamber is disposed on a silicon substrate in the form of a silicon wafer or a silicon chip.

13. The electrochemical device of claim 1 , wherein the electrochemical device is coupled operatively to an analytical instrument selected from the group consisting of: X-ray photoelectron spectroscopy (XPS); scanning electron microscopy (SEM); secondary ion mass spectrometry (SIMS); helium ion microscopy (HelM); Auger electron spectroscopy (AES); Rutherford backscattering spectrometry (RBS); transmission electron microscopy (TEM), and combinations thereof that provides simultaneous electrochemical analysis and chemical imaging when a sample is introduced into the electrochemical device.

14. A method for combined electrochemical analysis and chemical imaging of analytes present at a working electrode-liquid sample interface in-situ under vacuum, comprising:
introducing a liquid sample containing one or more analytes in a liquid flow path defined through a microfluidic flow chamber of a microfluidic electrochemical device;
delivering a selected potential between a working electrode and a reference electrode in the microfluidic flow chamber to drive reactions of the one or more analytes in the liquid sample as a function of time, space, and/or potential;
exposing the liquid sample to at least one probe beam from at least one analytical instrument under vacuum to provide chemical imaging of chemical and molecular species stemming from reactions of the one or more analytes at a selected depth or a selected layer of the liquid sample at the working electrode-liquid interface in-situ; and
measuring electrical current between the working electrode and a counter electrode to provide electrochemical analysis of chemical and molecular species stemming from reactions of the one or more analytes at the selected depth or layer of the liquid sample to provide chemical imaging and electrochemical analysis of the chemical and molecular species at the working electrode-liquid sample interface in-situ.

15. The method of claim 14 , wherein the liquid sample is an electrolyte solution or includes an electrolyte.

16. The method of claim 14 , wherein the liquid sample is a buffer solution or includes a buffer.

17. The method of claim 14 , wherein the microfluidic electrochemical device is configured as a bioreactor for growth and analysis of biofilms.

18. The method of claim 14 , wherein the liquid sample is a biological medium containing one or more biological analytes selected from: cells, bacteria, biofilm precursors, or combinations thereof.

19. The method of claim 14 , wherein the potential is delivered from, and current is measured by, an electrochemical workstation disposed external to the microfluidic electrochemical device.

20. The method of claim 14 , wherein the method includes simultaneous or individual electrochemical analysis by cyclic voltammetry and chemical imaging by an analytical method selected from the group consisting of: X-ray photoelectron spectroscopy (XPS); scanning electron microscopy (SEM); secondary ion mass spectrometry (SIMS); helium ion microscopy (HelM); Auger electron spectroscopy (AES); Rutherford backscattering spectrometry (RBS); transmission electron microscopy (TEM), and combinations thereof.

21. The method of claim 14 , wherein the method includes chemically imaging adsorbed molecules at the surface of the working electrode and/or in the liquid adjacent the working electrode in-situ.

22. The method of claim 14 , wherein the method includes following compositional changes of an electrolyte as a function of time in-situ.

23. The method of claim 14 , wherein the method includes a time-resolved and/or a space-resolved determination of reaction products and intermediate chemical species as electron transfer occurs in the sample in-situ.

24. The method of claim

Assignees

• Yu xiao-ying
• Liu Bingwen
• Yang Li
• Zhu Zihua
• Marshall Matthew J
• Battelle Memorial Institute

Inventors

• Yu xiao-ying
• Liu Bingwen
• Yang Li
• Zhu Zihua
• Marshall Matthew J

Classifications

• G01N27/447 Primary

  using electrophoresis · CPC title

• G01N23/2204

  Specimen supports therefor; Sample conveying means therefore · CPC title

• G01N21/75 Primary

  Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated (systems in which material is burnt in a flame or plasma G01N21/72, G01N21/73) · CPC title

• G01N27/403

  Cells and electrode assemblies · CPC title

• G01N27/27 Primary

  Association of two or more measuring systems or cells, each measuring a different parameter, where the measurement results may be either used independently, the systems or cells being physically associated, or combined to produce a value for a further parameter · CPC title