Analyte detection via electrochemically generated reagent

• US 20080241932A1
• Filed: 03/30/2007
• Published: 10/02/2008
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Teledyne Scientific & Imaging, LLC (Teledyne Technologies Incorporated)
• Original Assignee: Teledyne Licensing, LLC
• Inventors: DeNatale, Jeffrey F., Kendig, Martin W., Discenzo, Frederick M., Tench, D. Morgan, Chen, Chuan-Hua
• Granted Patent: US 8,153,062 B2
• Time in Patent Office: Days
• US Class Current: 436/2
• CPC Class Codes: G01N 21/272 for following a reaction, e.g. for determining photometrically a reaction rate (photometric cinetic analysis)
• CPC Class Codes: G01N 33/02 Food
• CPC Class Codes: G01N 33/1826 organic contamination in water
• CPC Class Codes: Y02A 20/20 Controlling water pollution; Waste water treatment

Abstract

Electrochemical devices, methods, and systems for detecting and quantifying analytes are disclosed. A chemical detection reagent is locally generated in a test solution by electrochemical reaction of a precursor compound caused to migrate into the test solution from a precursor solution separated from the test solution by a cell separator. This approach provides precise metering of the reagent, via the charge passed, and avoids the need to store a reagent solution that may be chemically unstable. In one embodiment, the starch concentration in a colloidal solution can be measured via spectroscopic detection of a blue complex formed by the interaction of starch with iodine produced, on demand, by electrochemical oxidation of iodide ion. The approach may also be used to characterize certain types of analytes. The invention is amenable to automation and is particularly useful for on-line monitoring of production processes, including the inclusion of feed back loop mechanisms for process control.

Claims

1. A device for detecting at least one analyte in a test solution, comprising:

at least one test solution compartment comprising the test solution;

at least one precursor solution compartment comprising a precursor solution, wherein the precursor solution comprises at least one precursor compound;

at least one cell separator between the at least one test solution compartment and the at least one precursor solution compartment, wherein the at least one separator inhibits mixing of the at least one test solution and the at least one precursor solution;

wherein

activation of the device permits at least some of the at least one precursor compound to migrate from the at least one precursor solution, through the at least one cell separator, and into the at least one test solution, thereby generating a reagent for detecting the at least one analyte.

2. The device of claim 1, further comprising:

at least one first electrode in contact with the at least one test solution;

at least one second electrode in contact with the at least one precursor solution; and

at least one electrical power source electrically connected across the at least one first electrode and the at least one second electrode,

wherein

the device is activated by an application of at least one quantity of electrical power between the at least one first electrode and the at least one second electrode.

3. The device of claim 1, wherein the cell separator comprises at least one porous material selected from the group consisting of semipermeable membranes, ceramics, glasses, plastics, silicon, polysilicon, and combinations thereof.

4. The device of claim 1, wherein the device comprises at least one of an electrochemical cell and a microfluidic device.

5. The device of claim 4, wherein the at least one microfluidic device includes at least one valve selected from the group consisting of a flow valve, a one-way valve, and combinations thereof.

6. The device of claim 1, wherein at least one of the at least one first electrode and the at least one second electrode comprises a noble metal selected from the group consisting of platinum, iridium, osmium, palladium, rhenium, rhodium, ruthenium, and combinations thereof.

7. The device of claim 1, further comprising a transport system for transporting at least one portion of the test solution from a test solution source to the at least one test solution compartment, from the at least one test solution compartment to a system for detecting the analyte, or both.

8. The device of claim 1, further comprising a detection system for detecting the analyte.

9. The device of claim 8, wherein the detection system is an optical detection system.

10. The device of claim 9, wherein the optical detection system comprises a light source, an optical cell and a light detector.

11. The device of claim 8, further comprising a measurement system for quantifying the amount of analyte detected by the device.

12. The device of claim 11, wherein the amount of analyte is quantified by measuring the light absorbance of the test solution.

13. The device of claim 8, further comprising an analytic system for characterizing the analyte detected by the device.

22. A method for detecting at least one analyte in a test solution, the method comprising application of at least one quantity of electrical power between the at least one first electrode and the at least one second electrode of a device according to claim 1, thereby causing at least some of the at least one precursor compound to migrate from the at least one precursor solution to the at least one test solution, where it reacts electrochemically at or near the at least one first electrode to generate at least one reagent for detecting the at least one analyte.

14. A device for detecting starch in a test solution, comprising:

a test solution compartment comprising the test solution;

a precursor solution compartment comprising a precursor solution comprising iodide ion;

a cell separator between the test solution compartment and the precursor solution compartment that inhibits solution mixing but permits transfer of iodide ion from the precursor solution to the test solution;

an anode in contact with the test solution;

a cathode in contact with the precursor solution;

an electrical power source electrically connected across the anode and the cathode,

whereby electrical power applied between the anode and cathode causes iodide ion to migrate through the cell separator from the precursor solution to the test solution and be oxidized at the anode to iodine, and the iodine generated combines with starch in the test solution to produce a starch-iodine complex.

15. The device of claim 14, wherein the concentration of iodide ion in the precursor solution is within the range from about 0.01 to about 1.0 M.

16. The device of claim 14, further comprising a transport system for transporting at least a portion of the test solution from a test solution source to the device, from the device to a system for detecting the analyte, or both.

17. The device of claim 14, further comprising a detection system for detecting the starch-iodine complex in the test solution.

18. The device of claim 17, wherein the detection system comprises a light source, an optical cell and a light detector.

19. The device of claim 17, wherein the complex is detected by measuring the light absorbance of the test solution at one or more wavelengths.

20. The device of claim 19, wherein the one or more wavelengths is within the range of from about 400 nm to about 800 nm.

21. The device of claim 17, further comprising a measurement system for quantifying the amount of the analyte detected by the device.

23. A method for detecting an analyte in a test solution, comprising the steps of:

providing an electrochemical cell comprising a first electrode in contact with a test solution in a test solution compartment, a second electrode in contact with a precursor solution comprising a precursor compound in a precursor compartment, and a cell separator between the test solution compartment and the precursor compartment, wherein the separator inhibits mixing of the test solution and the precursor solution;

applying a quantity of electrical power between the first electrode and the second electrode, thereby causing at least some of the precursor compound to migrate through the cell separator and electrochemically react at the first electrode to generate a reagent for detecting the analyte.

24. A method for quantifying the starch concentration in a test solution, comprising the steps of:

providing an electrochemical cell comprising an anode in contact with a test solution in a test solution compartment, a cathode in contact with a precursor solution comprising iodide ion in a precursor solution compartment, and a cell separator between the test solution compartment and the precursor solution compartment that inhibits mixing of the test solution and the precursor solution;

applying a quantity of electrical power between the anode and the cathode, thereby causing at least some of the iodide ion to migrate through the cell separator and be oxidized at the anode to iodine;

measuring the light absorbance at one or more wavelengths for at least one portion of the test solution comprising the iodine;

generating a calibration curve by repeating the preceding steps for a plurality of calibration solutions of known starch concentrations, in place of the test solution; and

comparing the absorbance of the test solution with the calibration curve to determine the concentration of starch in the test solution.