Differential electrochemical mass spectrometry (DEMS) cell

1. A differential electrochemical mass spectrometry (DEMS) cell, comprising:

a body, the body defining an anolyte chamber, a catholyte chamber, and a collection chamber;

an ion-conducting membrane separating the anolyte chamber and the catholyte chamber;

a counter electrode disposed in the anolyte chamber;

a working electrode disposed in the catholyte chamber, the working electrode being a washer-shaped electrode and a channel being defined in a center of the working electrode, the channel functioning as an inlet for catholyte to the catholyte chamber; and

a pervaporation membrane, a first surface of the pervaporation membrane defining a portion of the collection chamber, and the collection chamber being in fluid communication with the catholyte chamber.

2. The DEMS cell of claim 1 , wherein the catholyte chamber has a cylindrical shape, wherein a plurality of down channels are defined in the body between the catholyte chamber and the collection chamber, and wherein an inlet for the catholyte for each of the plurality of down channels is defined in the cathode chamber along a diameter of the catholyte chamber.

3. The DEMS cell of claim 2 , wherein the plurality of down channels defined in the body between the catholyte chamber and the collection chamber consists of four down channels, and wherein the inlet for each of the four down channels is positioned symmetrically about the diameter of the catholyte chamber.

4. The DEMS cell of claim 2 , wherein the catholyte is operable to flow into the catholyte chamber through the channel, to flow outwards from the center of the working electrode to the inlets of the plurality of down channels, and to flow into the collection chamber.

5. The DEMS cell of claim 1 , wherein anolyte is operable to flow into the anolyte chamber, to flow along a surface of the ion-conducting membrane, and to flow out of the anolyte chamber.

6. The DEMS cell of claim 1 , wherein the counter electrode comprises platinum.

7. The DEMS cell of claim 1 , wherein a surface area of the counter electrode is about 2 cm 2 .

8. The DEMS cell of claim 1 , wherein the ion-conducting membrane comprises a proton conducting membrane.

9. The DEMS cell of claim 1 , wherein a surface area of the ion-conducting membrane between the working electrode and the counter electrode is about 1.75 cm 2 .

10. The DEMS cell of claim 1 , wherein a distance between the working electrode and the ion-conducting membrane is about 10 microns to 200 microns.

11. The DEMS cell of claim 1 , wherein a volume of the catholyte chamber is less than about 40 microliters.

12. The DEMS cell of claim 1 , wherein the working electrode comprises copper.

13. The DEMS cell of claim 1 , wherein a surface area of the working electrode is about 0.5 cm 2 to 2 cm 2 .

14. The DEMS cell of claim 1 , further comprising:

a screw, wherein the screw passes through the channel and connects the working electrode to the body, and wherein the screw defines a second channel through which the catholyte is operable to flow into the catholyte chamber.

15. The DEMS cell of claim 1 , wherein the counter electrode defines a flat surface, and wherein the working electrode and the flat surface of the counter electrode are parallel.

16. The DEMS cell of claim 1 , wherein the pervaporation membrane comprises polytetrafluoroethylene (PTFE).

17. The DEMS cell of claim 1 , further comprising:

a stainless steel frit, wherein the stainless steel frit is in contact with a second surface of the pervaporation membrane.

18. The DEMS cell of claim 1 , further comprising:

a reference electrode disposed in the catholyte chamber.

19. The DEMS cell of claim 18 , wherein the reference electrode is positioned about 1 millimeter from the working electrode.