Multimode electrochemical sensing array
View Patent ↗A multimode electrochemical sensing array formed on an integrated circuit chip is structured to provide electrochemical determination of acidity or alkalinity, as well as electrochemical and potentiometric measurement of oxidation/reduction potentials, conductivity measurements, electrostatic discharge protection, and ground provisioning.
1. A multimode electrochemical sensing array comprising a semiconductor chip having formed thereon:
A. an Ion Selective Field Effect Transistor, said transistor having an exposed Gate for contact with a test solution when immersed therein, said Gate being surrounded by, but spaced from, a conductive surface that serves as both an electrode and a light shield for the transistor;
B. a plurality of electrodes spaced remotely from said transistor, at least one of said electrodes being connectable in circuit with said conductive surface and with an external current source to provide a current for electrochemical determination of two or more parameters of said solution.
2. A multimode electrochemical sensing array according to claim 1 in which said current source is polarized to provide a titrant in the vicinity of said Gate.
3. A multimode electrochemical sensing array according to claim 1 in which said current source is polarized to provide a titrant in the vicinity of said at least one remotely spaced electrode.
4. A multimode electrochemical sensing array according to claim 1 in which said remotely spaced electrodes includes comprise a first pair of electrodes, each of a first area, and a second pair of electrodes, each of a smaller area than said first area, said electrodes being connectable in circuit with an external current source and an external voltage meter to provide conductivity measurements of a test solution in which they are immersed.
5. A multimode electrochemical sensing array according to claim 1 in which said remotely spaced electrodes include at least one electrode for performing oxidation/reduction measurements with respect to an external reference electrode.
6. A multimode electrochemical sensing array according to claim 1 in which said remotely spaced electrodes include at least one electrode connectable through a potential regulating element to said conductive surface for limiting the potential on said surface.
7. A multimode electrochemical sensing array according to claim 6 in which said potential regulating element comprises a varistor.
8. A multimode electrochemical sensing array according to claim 1 in which said remotely spaced electrodes include at least one electrode connectable to ground to thereby connect a test solution to ground potential when desired.
9. A multimode electrochemical sensing array according to claim 1 in which said at least one electrode is connectable in circuit with an external source of constant current.
10. A multimode electrochemical sensing array according to claim 1 in which said at least one electrode is connectable in circuit with an external source of current that increases during its application.
11. A multimode electrochemical sensing array according to claim 1 in which said at least one electrode is connectable in circuit with an external source of current that increases linearly during its application over at least some range thereof.