Analyte sensor

1. A voltammetric sensor for use in conjunction with a pH meter, said voltammetric sensor-comprising:

(i) a working electrode having a central opening;

(i) an internal working electrode aligned with the central opening of the working electrode, said internal working electrode being non-covalently coated with a matrix material, said matrix material having an analyte sensitive material (ASM) or an analyte insensitive material (AIM) covalently attached thereto or non-covalently entrapped therein;

(ii) a constant chemical environment aligned with and disposed within the central opening of the working electrode and interposed between the internal working electrode and the counter electrode and in contact with the ASM or AIM of the matrix material, and selected from the group consisting of a liquid, a semi-solid, and a solid comprising a buffer solution and at least one of:

(a) a viscosity enhancer;

(b) a gelling agent;

(c) a zwitterionic polymer; and

(d) an ionomer formulated to render a specific potential in conjunction with the internal working electrode;

(iii) an analyte barrier aligned with the central opening of the working electrode, said constant chemical environment being interposedly positioned between said internal working electrode and said analyte barrier; and

(iv) a pseudo reference electrode having a tip positioned in the constant chemical environment and a body passing through the internal working electrode.

2. The voltammetric sensor of claim 1 , wherein the analyte barrier is an ionomer.

3. The voltammetric sensor of claim 1 , wherein the analyte barrier is a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer.

4. The voltammetric sensor of claim 1 , wherein the analyte barrier is a solid that substantially prevents convective flow.

5. The voltammetric sensor of claim 2 , wherein the ionomer is composed of Nafion (DuPont).

6. The voltammetric sensor of claim 1 , wherein either or both of the constant chemical environment and the analyte barrier comprises a porous reinforcing matrix.

7. The voltammetric sensor of claim 1 , wherein the pseudo-reference electrode, the internal working electrode, and the constant chemical environment are in the solid state.

8. The voltammetric sensor of claim 1 capable of wet-dry reversible operation.

9. A voltammetric sensor for use in conjunction with a pH meter, said voltammetric sensor comprising (i) components of the voltammetric sensor of claim 1 ; and (ii) electronic components and algorithm that convert an electronic signal output representing the measured pH value into a corresponding electrical potential that a pH meter can accept, process, display, and optionally further communicate with other computing devices, instrumentation and control systems.

10. The voltammetric sensor of claim 1 , wherein the matrix material comprises a cross-linked polymer selected from the group consisting of a polyol, a poly(vinyl alcohol), a polysulfone, a polyethersulfone, a polyimide, a polysulfonamide, a polyimide, a polyester, a vinyl polymer, a polyphenylene sulfide, a polysaccharide, and cellulose.

11. The voltammetric sensor of claim 1 , wherein the constant chemical environment comprises a zwitterionic polymer.

12. The voltammetric sensor of claim 1 , wherein the analyte barrier is a zwitterionic polymer.

13. The voltammetric sensor of claim 1 , wherein the constant chemical environment comprises an ionomer formulated to render a specific potential in conjunction with the internal working electrode.