Claims
- 1. A flowing junction reference electrode comprising:
a microfluidic liquid junction member situated between a reference electrolyte solution and a sample solution, the microfluidic liquid junction member having an array of nanochannels; wherein the reference electrolyte solution flows through the array of nanochannels and into the sample solution at a linear velocity, and wherein the sample solution does not substantially enter the array of nanochannels.
- 2. The electrode of claim 1, wherein the number of nanochannels is less than approximately 108 and greater than approximately 10.
- 3. The electrode of claim 2, wherein the number of nanochannels is less than approximately 106.
- 4. The electrode of claim 2, wherein the number of nanochannels is less than approximately 105.
- 5. The electrode of claim 2, wherein the number of nanochannels is less than approximately 104.
- 6. The electrode of claim 2, wherein the number of nanochannels is greater than approximately 100.
- 7. The electrode of claim 1, wherein the nanochannels are substantially straight and substantially parallel to one another.
- 8. The electrode of claim 1, wherein the width of any nanochannel in the array of nanochannels is substantially equal to the width of any other nanochannels in the array of nanochannels.
- 9. The electrode of claim 1, wherein the nanochannels have widths of greater than approximately 1 nanometer and less than approximately 900 nanometers.
- 10. The electrode of claim 1, wherein the nanochannels have widths of greater than approximately 10 nanometers and less than approximately 100 nanometers.
- 11. The electrode of claim 1, wherein the nanochannels are coated.
- 12. The electrode of claim 1 wherein the junction member is constructed of a polymer.
- 13. The electrode of claim 12 wherein the polymer is selected from the group consisting of polycarbonate and polyimide.
- 14. The electrode of claim 1 wherein the junction member is constructed of silicon, glass, or ceramic.
- 15. The electrode of claim 1, further comprising means for maintaining positive linear flow of the reference electrolyte solution through the array of nanochannels and into the sample solution.
- 16. The electrode of claim 15 wherein the means for maintaining positive linear flow of electrolyte flow is selected from the group consisting a pressurized collapsible bladder, an electro-osmotic pump, a mechanical pump, a piezo-electric pump, and a electro-hydrodynamic pump.
- 17. A combination electrode comprising:
a flowing liquid junction reference electrode comprising a microfluidic junction member situated between a reference electrolyte solution and a sample solution, the microfluidic junction member having an array of nanochannels; wherein the reference electrolyte solution flows through the array of nanochannels and into the sample solution at a linear velocity, and wherein the sample solution does not substantially enter into the array of nanochannels; and a sensing electrode.
- 18. The combination electrode of claim 17, wherein the sensing electrode is selected from the group consisting of pH electrodes, other ion-selective electrodes, and redox electrodes.
- 19. A microfluidic flowing liquid junction reference electrode comprising:
a reference electrolyte solution flowing through a junction member and into a sample solution; wherein substantially no sample solution enters into the junction member.
- 20. The reference electrode of claim 19 wherein the linear velocity of the reference electrolyte solution flowing into the sample solution is greater than approximately 0.1 cm per second.
- 21. The reference electrode of claim 20 wherein the volumetric flow rate of the reference electrolyte solution into the sample solution is less than approximately 60 μL per hour.
- 22. The reference electrode of claim 20 wherein the volumetric flow rate of the reference electrolyte solution into the sample solution is less than approximately 10 μL per hour.
- 23. A microfluidic flowing liquid junction reference electrode capable of having a lifetime of greater than one year, during which variations of electrolytic potential are less than approximately 1 mV, and during which less than approximately 100 mL of electrolyte flows into the sample solution.
- 24. The electrode of claim 23 wherein the lifetime is greater than two years.
- 25. The electrode of claim 23, wherein the resistance across the junction member is less than approximately 1 megohm.
- 26. The combination electrode of claim 17, further comprising a calibration circuit.
- 27. The combination electrode of claim 26, wherein the calibration circuit substantially nulls the offset.
- 28. The combination electrode of claim 26, wherein the calibration circuit substantially optimizes the slope of the sensor response, as measured between two distinct standard solutions.
- 29. The combination electrode of claim 26, wherein the calibration circuit substantially nulls the offset and substantially optimizes the slope of the sensor response, as measured between two distinct standard solutions.
- 30. A combination electrode comprising the reference electrode of claim 1, a sensing electrode, and a calibration circuit.
- 31. The combination electrode of claim 30, wherein the calibration circuit substantially nulls the offset.
- 32. The combination electrode of claim 30, wherein the calibration circuit substantially optimizes the slope of the sensor response, as measured between two distinct standard solutions.
- 33. The combination electrode of claim 30, wherein the calibration circuit substantially nulls the offset and substantially optimizes the slope of the sensor response, as measured between two distinct standard solutions.
PRIORITY CLAIM
[0001] The present application claims priority to U.S. patent application Ser. No. 09/590,781, filed Jun. 8, 2000, which in turn claims priority to U.S. Provisional Patent Application Ser. No. 60/138,141, filed Jun. 8, 1999.
Government Interests
[0002] This invention was made with United States Government support under SBIR Phase I Grant No. DMI-9960665 awarded by the National Science Foundation. The United States Government has certain rights in this invention.
Provisional Applications (1)
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Number |
Date |
Country |
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60138141 |
Jun 1999 |
US |