Planar bicarbonate sensor
First Claim
1. A planar bicarbonate sensor comprising an electrically nonconductive substrate having applied thereto in a planar format an electrically conductive material in at least one region adjacent to said substrate;
- a dielectric coating covering at least a lead portion of said electrically conductive material but leaving exposed at least an electrode area of said electrically conductive material and leaving exposed at least a contact area on said region of said electrically conductive material;
a silver/silver halide transducer present adjacent to said electrically conductive material in said exposed electrode area;
an internal electrolyte residue layer present on top of and adjacent to said transducer;
a cover membrane present on top of and adjacent to said internal electrolyte residue layer, wherein said internal electrolyte residue layer is an aqueous solution comprised of from about 0.0002 M to about 0.0003 M of a bicarbonate source, and a halide salt of potassium, lithium, or sodium, wherein said internal electrolyte residue layer has been dried.
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Accused Products
Abstract
A planar bicarbonate sensor has been discovered that has a dried residue internal electrolyte layer comprising a bicarbonate source and a halide salt of potassium, lithium, or sodium. The flow-through sensor is capable of providing bicarbonate level of a liquid sample, and when coupled with a pH sensor, may be used to determine the partial carbon dioxide level in the sample. The sensor provides many commercially desirable characteristics including an adequate lifetime, good response time, and good stability upon first usage.
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Citations
7 Claims
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1. A planar bicarbonate sensor comprising an electrically nonconductive substrate having applied thereto in a planar format an electrically conductive material in at least one region adjacent to said substrate;
- a dielectric coating covering at least a lead portion of said electrically conductive material but leaving exposed at least an electrode area of said electrically conductive material and leaving exposed at least a contact area on said region of said electrically conductive material;
a silver/silver halide transducer present adjacent to said electrically conductive material in said exposed electrode area;
an internal electrolyte residue layer present on top of and adjacent to said transducer;
a cover membrane present on top of and adjacent to said internal electrolyte residue layer, wherein said internal electrolyte residue layer is an aqueous solution comprised of from about 0.0002 M to about 0.0003 M of a bicarbonate source, and a halide salt of potassium, lithium, or sodium, wherein said internal electrolyte residue layer has been dried. - View Dependent Claims (2, 3, 4, 5, 6)
- a dielectric coating covering at least a lead portion of said electrically conductive material but leaving exposed at least an electrode area of said electrically conductive material and leaving exposed at least a contact area on said region of said electrically conductive material;
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7. A method of preparing a bicarbonate sensor, said method comprising selecting a substrate;
- applying an electrically conductive region on at least a portion of said substrate;
coating said electrically conductive region with a dielectric but leaving exposed a transducer region on said electrically conductive region and a contact region on said electrically conductive region;
forming a silver/silver halide layer on said transducer region to form a transducer;
forming an internal electrolyte dried residue layer having a dried thickness of from about 2.5 μ
m to about 4 μ
m thickness on at least said transducer portion of said sensor wherein said internal electrolyte residue layer is prepared from an aqueous solution comprising a bicarbonate source in an amount ranging from about 0.0002 M to about 0.0003 M, and a halide salt of potassium, lithium, sodium; and
forming on top of and adjacent to at least said dried internal electrolyte residue layer a cover membrane layer having a thickness of from about 20 to about 60 μ
m by forming a solution comprising an organic solvent, a gas permeable polymeric or copolymeric material, a proton selective ionophore, a plasticizer, and a lipophilic salt present in an amount ranging form about 0.1 wt. % to about 0.5 wt. %, and then drying said solution to form said cover membrane layer.
- applying an electrically conductive region on at least a portion of said substrate;
Specification