Electrochemical sensors
Systems and methods are provided for detecting the presence of an analyte in a sample. A solid state electrochemical sensor can include a redox active moiety having an oxidation and/or reduction potential that is sensitive to the presence of an analyte immobilized over a surface of a working electrode. A redox active moiety having an oxidation and/or reduction potential that is insensitive to the presence of the analyte can be used for reference. Voltammetric measurements made using such systems can accurately determine the presence and/or concentration of the analyte in the sample. The solid state electrochemical sensor can be robust and not require calibration or re-calibration.
1. A sensor for detecting the presence or absence of an analyte, comprising:
a first solid state electrode having a surface having immobilized thereon a layer of a first redox-active moiety, wherein the first redox-active moiety has an oxidation potential and/or a reduction potential that is sensitive to the presence of the analyte; and
a second solid state electrode having a surface having immobilized thereon a layer of a second redox-active moiety and a layer of a polymeric material adjacent to the layer of the second redox-active moiety, wherein the second redox-active moiety has an oxidation potential and/or reduction potential that is sensitive to the presence of the analyte.
2. The sensor of claim 1 , wherein the layer of the polymeric material is a light blocking layer.
3. The sensor of claim 2 , wherein the polymeric material comprises polyethersulphone.
4. The sensor of claim 1 , further comprising a protective layer adjacent to the layer of the polymeric material.
5. The sensor of claim 4 , wherein the protective layer comprises another polymeric material.
6. The sensor of claim 1 , wherein the polymeric material has the formula C 7 HF 13 O 5 S*C 2 F 4 .
7. The sensor of claim 1 , wherein the layer of the polymeric material comprises a porous plastic.
8. The sensor of claim 1 , wherein the first or second solid state electrode comprises carbon.
9. The sensor of claim 1 , wherein the first or second solid state electrode comprises silicon.
10. The sensor of claim 1 , wherein the layer of the polymeric material comprises pores.
11. The sensor of claim 10 , wherein said pores have a pore size between about 0.1 micrometers and 1 micrometer.
12. The sensor of claim 1 , wherein the analyte is hydrogen ion.
13. The sensor of claim 1 , wherein the layer of the polymeric material is an ion selective layer.
14. A solid state sensor for detecting the presence or absence of an analyte, comprising (i) a solid state electrode having a surface having immobilized thereon a layer of a redox-active moiety, (ii) a layer of a polymeric material and (iii) a protective layer adjacent to the layer of the polymeric material, wherein the layer of the polymeric material is porous and covers the layer of the redox-active moiety, wherein the redox-active moiety has an oxidation potential and/or a reduction potential that is directly sensitive to the presence of the analyte, and wherein the redox-active moiety is immobilized on the surface through a covalent interaction with the solid state electrode.
15. The solid state sensor of claim 14 , further comprising a light blocking layer adjacent to the layer of the polymeric material.
16. The solid state sensor of claim 15 , wherein the light blocking layer transmits less than 10% of light incident on the light blocking layer.
17. The solid state sensor of claim 16 , wherein the light blocking layer transmits less than 5% of light incident on the light blocking layer.
18. The solid state sensor of claim 17 , wherein the light blocking layer transmits less than 1% of light incident on the light blocking layer.
19. The solid state sensor of claim 14 , wherein the analyte is hydrogen ion.
20. The solid state sensor of claim 14 , wherein the solid state electrode comprises silicon.
21. The solid state sensor of claim 14 , wherein the layer of the polymeric material is an ion selective layer.
22. The solid state sensor of claim 1 , wherein the solid state electrode is non-metallic.
23. The solid state sensor of claim 14 , wherein the layer of the polymeric material selectively screens off anions and only allows the passage of cations.