Capacitive chemical sensor for detecting certain analytes, including hydrocarbons in a liquid medium
First Claim
1. A device for sensing selected analyte in a liquid medium, comprising:
- a concentrating and nucleating material adapted to be exposed to a liquid medium under test, for causing nucleated formation of bubbles in a liquid medium on the surface of said material in response to selected analyte contained in said liquid medium; and
,a means, positioned in association with said concentrating and nucleating material, responsive to the formation of said bubbles.
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Accused Products
Abstract
An apparatus for detecting the concentration of certain analytes, including hydrocarbons, in a liquid medium, is disclosed. The apparatus uses a planar or "open" capacitor containing an active layer. In response to selected analyte in the liquid medium, the active layer causes capacitance to decrease with increasing analyte concentration. The capacitance decreases because higher dielectric water molecules are displaced from a region of the capacitor'"'"'s electric field. For certain hydrocarbon analytes having high Henry'"'"'s Law constants, the active layer causes bubbles to nucleate in the liquid medium on the surface of the active layer. Bubble formation displaces water molecules and decreases capacitance.
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Citations
45 Claims
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1. A device for sensing selected analyte in a liquid medium, comprising:
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a concentrating and nucleating material adapted to be exposed to a liquid medium under test, for causing nucleated formation of bubbles in a liquid medium on the surface of said material in response to selected analyte contained in said liquid medium; and
,a means, positioned in association with said concentrating and nucleating material, responsive to the formation of said bubbles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for sensing a selected analyte in a liquid medium, comprising:
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a capacitor having at least one pair of spaced apart electrode elements; and
,a concentrating and nucleating material positioned in association with said electrode elements and adapted to be exposed to liquid medium under test, for causing nucleated formation of bubbles in a liquid medium on the surface of said concentrating and nucleating material, thereby decreasing capacitance with increasing analyte concentration. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A device for sensing a hydrocarbon analyte in an aqueous selection, comprising:
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a capacitor having at least one pair of spaced apart electrode elements; and
,a layer of polymeric material positioned in association with said electrode elements and adapted to be exposed to an aqueous solution under test, for causing nucleated formation of bubbles in the aqueous solution on the surface of said layer in response to presence of hydrocarbon analytes in said aqueous solution, thereby decreasing capacitance with increasing concentration of said hydrocarbon analyte. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A differential sensor for sensing hydrocarbon analyte in a liquid medium comprising:
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a first capacitor having at least one pair of spaced apart electrode elements; a layer of polymeric material positioned in association with said electrode elements of said first capacitor and adapted to be exposed to a liquid medium under test, for causing nucleated formation of bubbles in the liquid medium on a surface of said layer in response to analyte hydrocarbon contained in the liquid medium; a second capacitor having at least one pair of spaced apart electrode elements; a layer of electrically insulating material coating said spaced apart electrode elements of said second capacitor and adapted to the exposed to said liquid medium under test; and
,an electronic means, operably connected to said first and second capacitor for calculating the hydrocarbon concentration in said liquid medium. - View Dependent Claims (32, 33, 34, 35, 36)
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37. A device for sensing a hydrocarbon analyte in a liquid medium comprising:
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a substrate; a plurality of spaced apart finger electrodes positioned on said substrate to form an open sensor capacitor; a first electrically insulating layer coating said finger electrodes of said sensor capacitor; and
,a second layer of polymeric material coating said first layer and at least partially filling a volume between said spaced apart finger electrodes and adapted to be exposed to the liquid medium under test, wherein said polymeric material has an affinity for non-polar hydrocarbon molecules, thereby causing a decrease in capacitance of said sensor capacitor with increasing hydrocarbon concentration. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45)
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Specification