Solid state graphite electrode
First Claim
1. An electrode for use in making potentiometric measurements comprising,a graphite conductor;
- means supporting said graphite conductor;
means for electrically connecting said graphite conductor to a means for sensing a difference in electrical potential between the electrode and a reference source; and
an organic liquid coating said graphite surface and chemically bonding therewith so as to render that surface hydrophobic.
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Accused Products
Abstract
A solid state graphite electrode to determine the activity of an ion-specie in solution. The graphite electrode of the present invention can be adapted for use as either an external reference electrode, an ion-selective electrode or as an internal reference electrode. The electrode includes, as an electrically conductive element, a supported section of graphite that is appropriately electrically connected through a potentiometer to show a difference in ion concentration as a voltage potential or emf. One graphite surface for immersion in a test solution is hydrophobized by coating it with a solution that contains an organic liquid molecule to covalently bond with hydroxyl groups (OH) of the graphite surface, rendering that surface hydrophobic. Preferably, the organic liquid is a silanizing agent, which coating after drying is covered with a hydrophobic layer or membrane that is preferably a polyvinylchloride (PVC) plastic. For an ion-selective electrode, an ion sensor for the ion to be sensed is mixed in the membrane material coated over the hydrophobized graphite and in another embodiment for an internal reference electrode, a hydrophilic membrane containing pairs of a same chemical specie in differing oxidation states or redox couple can be sandwiched therebetween.
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Citations
31 Claims
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1. An electrode for use in making potentiometric measurements comprising,
a graphite conductor; -
means supporting said graphite conductor; means for electrically connecting said graphite conductor to a means for sensing a difference in electrical potential between the electrode and a reference source; and an organic liquid coating said graphite surface and chemically bonding therewith so as to render that surface hydrophobic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An ion-selective electrode for use in making potentiometric measurements comprising,
a graphite conductor; -
means supporting said graphite conductor; means for connecting said graphite conductor to a means for sensing a difference in electrical potential between the electrode and a reference source; an organic liquid coating said graphite surface and chemically bonding therewith to render that surface hydrophobic; and an ion-selective membrane applied over said organic liquid coated graphite surface for sensing an ionic-specie therein. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. An electrode for making ion-selective measurements comprising,
a graphite conductor; -
means supporting said graphite conductor; an electrically conductive means connected to said graphite conductor; and an organic liquid coating said graphite surface and chemically bonding therewith so as to render that surface hydrophoic. - View Dependent Claims (31)
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Specification