Capacitive chemical sensor using an ion exchange surface

Claim 3

The device of claim 1, wherein each of said ion exchange molecules includes a cation exchange site and wherein each of said counter ion molecules carries a positively charged site.

Claim 4

The device of claim 1, wherein each of said ion exchange molecules includes an ion exchange site and wherein each of said counter-ion molecules a negatively charged site.

Claim 5

The device of claim 1, wherein each of said electrode elements comprises a plurality of spaced apart finger electrodes.

Claim 6

The device of claim 1, wherein said counter-ion molecules are selected from the group consisting of protein molecules and fatty acids.

Claim 7

The device of claim 1, wherein said counter-ion molecules are large compared to water molecules and have a lower dielectric constant than water molecules.

Claim 8

The device of claim 1, wherein said electrode elements are made from doped semiconductor material.

Claim 9

The device of claim 1, wherein said electrical elements are made from electrically conductive material.

Claim 10

The device of claim 1, further comprising an electronic means, operably coupled to second capacitor, for measuring and displaying a change in capacitance.

Claim 11

The device of claim 1, wherein said capacitor is positioned in a chamber, said chamber adapted to be at least partially filled with said test liquid.

Claim 12

The device of claim 10, wherein said chamber includes an opening exposed to said test liquid containing analyte ions.

Claim 13

The device of claim 11, wherein a membrane covers said opening, said membrane having pores sized to prevent escape of counter-ion molecules from said chamber.

Claim 14

A differential sensor for sensing analyte ions in a liquid, comprising: a first capacitor having at least one pair of spaced apart electrode elements said first capacitor comprising, a. an electrically insulating layer covering said electrode elements, b. a first layer of ion exchange molecules coating said electrically insulting layer, c. a second layer of counter-ion molecules attached to molecules of said first layer, said second layer adapted to be covered by a test liquid containing analyte ions of interest so that counter-ion molecules are displaced from said first layer by said analyte ions in said test liquid until a dynamic equilibrium is obtained; a second capacitor having at least one pair of spaced apart electrode elements and a layer of electrically insulating material coating said spaced apart electrode elements of said second capacitor and adapted to be exposed to said test liquid; and, an electronic means, operably coupled to said first and second capacitor for calculating the analyte concentration of the test liquid wherein analyte ions in the test liquid will displace a portion of said counter-ions from the surface of said ion exchange layer thereby changing the capacitance of said first capacitor.

Claim 15

A differential sensor for sensing analyte ions in a liquid, comprising: a first capacitor having at least one pair of spaced apart electrode elements said first capacitor comprising, a. an electrically insulating layer covering said electrode elements, b. a first layer of ion exchange molecules coating said electrically insulting layer, c. a second layer of counter-ion molecules attached to molecules of said first layer, said second layer adapted to be covered by a test liquid containing analyte ions of interest so that counter-ion molecules are displaced from said first layer by said analyte ions in said test liquid until a dynamic equilibrium is obtained; a second capacitor having at least one pair of spaced apart electrode elements and a layer of electrically insulating material coating said spaced apart electrode elements of said second capacitor and adapted to be exposed to said test liquid; and, an electronic means, operably coupled to said first and second capacitor for calculating the analyte concentration of the test liquid wherein analyte ions in the test liquid will displace a portion of said counter-ions from the surface of said ion exchange layer thereby changing the capacitance of said first capacitor.

Claim 16

The device of claim 13, wherein said counter-ion molecules are selected from the group consisting of protein molecules and fatty acids.

Claim 17

The device of claim 13, wherein in said counter-ion molecules are large compared to water molecules and have a lower dielectric constant than water molecules.

Claim 18

The device of claim 13, wherein said counter-ion molecules are larger than the analyte ion.

Claim 19

The device of claim 13, wherein said electrode elements for said first and second capacitor are made from doped semiconductor material.

Claim 20

The device of claim 13, wherein said electrode elements for said first and second capacitor are made from electrically conducted material.

Claim 21

The device of claim 13, wherein each of said ion exchange molecules have a cation exchange side and wherein each of said counter-ion molecules carries a positively charged site.

Claim 22

The device of claim 13, wherein each of said ion exchange molecules have an ion exchange site and wherein each of said counter-ion molecules carries a negatively charged site.

Claim 23

The device of claim 13, wherein said first and second capacitors are positioned in a chamber.

Claim 24

The device of claim 21, wherein said chamber includes an opening exposed to said test liquid containing analyte ions.

Claim 25

The device of claim 22, wherein a membrane covers said opening, said membrane having pores sized to prevent counter ion molecules from escaping from said chamber.

Claim 28

The device of claim 24, wherein said chamber means includes a means for introducing a liquid contain analyte into said chamber means.

Claim 29

The device of claim 25, further comprising: a second capacitor having at least one pair of spaced apart electrode elements and a layer of electrically insulating material coating said spaced apart electrode elements of said second capacitor and adapted to be exposed to said liquid containing analyte; and, a second means, associated with said second capacitor, responsive to the average dielectric properties in a volume adjacent to said insulating layer.