Bismuth-based electrochemical stripping analysis

• US 6,682,647 B1
• Filed: 05/10/2001
• Issued: 01/27/2004
• Est. Priority Date: 05/10/2000
• Status: Expired due to Fees

• Current Assignee: Arrowhead Center, Inc.
• Original Assignee: New Mexico State University Technology Transfer Corporation
• Inventors: Wang, Joseph
• Primary Examiner(s): Tung, T.
• Application Number:
  US09/854,291
• Time in Patent Office: 992 Days
• Field of Search: 205/775, 205/789, 205/789.5, 204/434, 204/292
• US Class Current: 205/775
• CPC Class Codes: G01N 27/42 Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte

Abstract

Method and apparatus for trace metal detection and analysis using bismuth-coated electrodes and electrochemical stripping analysis. Both anodic stripping voltammetry and adsorptive stripping analysis may be employed.

Claims

1. A method for analyzing metals in a solution sample comprising the steps of:

disposing an electrode into the solution sample;

adding a source of bismuth to the solution sample;

applying a current to the electrode to deposit a bismuth metal film thereon; and

then

analyzing the solution sample for metal content using electrochemical stripping analysis with the electrode.

2. The method of claim 1, wherein the electrode comprises carbon.

3. The method of claim 2, wherein the electrode is an electrode selected from the group consisting of glassy-carbon disk electrodes, carbon-fiber microelectrodes, thin-film electrodes and thick-film electrodes.

4. The method of claim 2, wherein the electrode is a screen-printed electrode.

5. The method of claim 1, further comprising the step of providing at least one reference electrode.

6. The method of claim 1, wherein the step of analyzing the solution sample for metal content using electrochemical stripping analysis comprises a method of analysis selected from the group consisting of stripping voltammetry and stripping potentiometry.

7. The method of claim 6, wherein the stripping voltammetry comprises anodic stripping voltammetry.

8. The method of claim 6, wherein the stripping voltammetry comprises adsorptive stripping voltammetry.

9. The method of claim 1, wherein the step of analyzing the solution sample for metal content further comprises use of bismuth as an internal standard.

10. The method of claim 1, wherein the step of analyzing the solution sample for metal content further comprises quantitative determination.

11. The method of claim 1, wherein the step of analyzing the solution sample for metal content further comprises analyzing the solution sample for more than one metal.

12. The method of claim 1, wherein the solution sample is a sample of body fluid.

13. The method of claim 1, wherein the concentration of bismuth in the solution sample is between about 500 μ

g/L and about 1000 mg/L.

14. A method for analyzing metals in a solution sample comprising the steps of:

disposing an electrode in a first solution comprising bismuth;

electrolytically depositing a bismuth metal film on the electrode;

removing the electrode from the first solution and disposing it into the sample solution; and

applying a current to the electrode and analyzing the solution sample for metal content using electrochemical stripping analysis.

15. The method of claim 14, wherein the electrode comprises carbon.

16. The method of claim 15, wherein the electrode is an electrode selected from the group consisting of glassy-carbon disk electrodes, carbon-fiber microelectrodes, thin-film electrodes and thick-film electrodes.

17. The method of claim 15, wherein the electrode is a screen-printed electrode.

18. The method of claim 14, further comprising the step of providing at least one reference electrode.

19. The method of claim 14, wherein the step of analyzing the solution sample for metal content using electrochemical stripping analysis comprises a method of analysis selected from the group consisting of stripping voltammetry and stripping potentiometry.

20. The method of claim 19, wherein the stripping voltammetry comprises anodic stripping voltammetry.

21. The method of claim 19, wherein the stripping voltammetry comprises adsorptive stripping voltammetry.

22. The method of claim 14, wherein the step of analyzing the solution sample for metal content further comprises quantitative determination.

23. The method of claim 14, wherein the step of analyzing the solution sample for metal content further comprises analyzing the solution sample for more than one metal.

24. The method of claim 14, wherein the solution sample is a sample of body fluid.