Analyte and pH measuring sensor assembly and method

Claim 1

A combined electrochemical sensor assembly for measuring coupled analytes, comprising: a) means for holding the electrodes in space apart, insulated relationship and in electrical conducting contact with electrical circuitry for each electrode, where the means is a nonconducting substrate; b) a first electrode mounted on the substrate for electrical connection to an external lead from the substrate and positioned to contact sample fluid, wherein the electrode has: a conductor electrically connected to electrical circuitry, an ion selective membrane selective for permeation by a first analyte of the coupled analytes and electrolyte that maximizes the electronic response of the first analyte and that minimizes the electric response of the second analyte of the coupled analytes in converting the ionic potentials to electronic potentials and; c) a second electrode mounted on the substrate for electrical connection to an external lead from the substrate and in spaced apart relation to the first electrode and positioned to contact sample fluid, wherein the second electrode has; a conductor electrically connected to electrical circuitry, an ion selective membrane, and an electrolyte to maximize the electronic response of the other analyte in the coupled multi-analytes while minimizing the electronic response of the first analyte in the conversion of the ionic potentials of the multi-analytes to electronic potentials, wherein both electrodes give some electronic response for both analytes, wherein the membranes for each electrode have a first and second side and the membrane is positioned in the electrode for one side to be in contact with the electrolyte of that electrode and the other side available for exposure to analyte-containing fluids and calibration fluids for analysis and the membrane holds the electrolyte in contact with the electrodes and provides for entry of the analyte into the electrolyte; d) reference electrode mounted on the substrate for electrical connection to an external lead from the substrate and in spaced apart relation to the first and second electrodes and positioned to contact the sample fluid; e) electric circuitry on the substrate to electrically connect the electrodes to an external lead from the substrate for conveyance of electrical potentials and for electrical connection of the reference electrode to the first and second electrodes; f) fluid circuit in liquid contact with the first, second and reference electrodes and insulated from the conductive pathways from the electrodes and from any external leads from the substrate; g) analyzing means electrically connected to the external leads of the substrate to receive the electrical potentials from the electrodes and to calculate the numerical values from simultaneous equations as follows: ##EQU3## where: delta mV=change in millivolts A1=first analyte A2=second analyte E1=electrode constructed to favor the first analyte E2=electrode constructed to favor the second analyte SE1A1=sensitivity of the electrode favoring the first analyte for the first analyte SE1A2=sensitivity of the electrode favoring the first analyte for the second analyte SE2A1=sensitivity of the electrode favoring the second analyte for the first analyte SE2A2=sensitivity of the electrode favoring the second analyte for the second analyte f=final measurement i=initial measurement.

Claim 20

An apparatus of combined pH and carbon dioxide electrochemical sensors for measuring the pH and the partial pressure of carbon dioxide in fluids, comprising: a) nonconducting substrate suitable for carrying printed wiring circuits, b) a pH electrode mounted on the substrate for electrical connection to an external lead from the substrate and positioned to contact sample fluid, wherein the electrode has a gas permeable hydrophobic ion selective polymeric membrane of high molecular weight polymer selected from the group consisting of: poly(vinylchloride), poly(bisphenol-A carbonate), cellulose acetate, poly(methylmethacrylate), poly(vinylidene chloride), polystyrene, polyurethane, block copolymers of polysiloxane/poly(bisphenol-A carbonate), polymers and copolymers of lower alkyl acrylate and methacrylate, silicone rubber with ionophores of trioctylamine and an aqueous dielectric with a pH in the range of up to around 5; c) a carbon dioxide electrode mounted on the substrate for electrical connection to an external lead from the substrate and in spaced apart relation to the pH electrode and positioned to contact sample fluid, wherein the carbon dioxide electrode has an lower molecular weight gas permeable polymeric ion selective membrane selected from the group consisting of: poly(vinylchloride), poly(bisphenol-A carbonate), cellulose acetate, poly(methylmethacrylate), poly(vinylidene chloride), polystyrene, polyurethane, block copolymers of polysiloxane/poly(bisphenol-A carbonate), polymers and copolymers of lower alkyl acrylate and methacrylate, silicone rubber with ionophores of trioctylamine and an aqueous dielectric with a pH in the range of at greater than 7 to 14, and the difference in the pH between the electrolytes is at least 0.1, and wherein both electrodes give some electronic response for both analytes; d) reference electrode mounted on the substrate for electrical connection to an external lead form the substrate and in spaced apart relation to the pH and carbon dioxide electrodes and positioned to contact the sample fluid and electrically connected to the pH and carbon dioxide electrodes; (for each of or common to the electrodes) e) electric circuitry on the substrate to electrically connect the electrodes to an external lead from the substrate for conveyance of electrical potentials and for electrical connection of the reference electrode to the pH and carbon dioxide electrodes; f) fluid circuit filled with a fluid selected from the group consisting of storage fluid, hydrating fluid, calibrating fluid and sample fluid and mixtures of these, wherein with such mixtures the sample fluid is in contact with the analyte electrodes where the fluid circuit is in liquid contact with the first, second and reference electrodes and insulated from the electric circuitry of the substrate; and g) programmed computer means having the functions of analog input processing, analog to digital conversion, programmed microprocessing, and a date/time circuit and battery backup random access memory, and a power supply electrically connected to the external leads of the substrate to receive the electrical potentials form the electrodes and to calculate the numerical values from simultaneous equations as follows: delta mVCO.sub.2 =-(SEN[CO.sub.2 ][pH])(de.sub.l.sbsb.t a pH)-(SEN [CO.sub.2 ][CO.sub.2 ])(log CO.sub.2 f/CO.sub.2 i) delta mVpH=-(SEN[pH][pH])(delta pH)-(SEN[pH][CO.sub.2 ])(log CO.sub.2 f/CO.sub.2 i) so that upon measuring the calibration fluid for known values of pH and CO2: ##EQU5## where: delta pH=change in pH delta mV=change in millivolts SEN [pH][CO 2 ]=sensitivity of the pH electrode favoring the CO 2 analyte SEN[pH][pH]=sensitivity of the pH electrode favoring H + analyte for the second analyte SEN[CO 2 ][pH]=sensitivity of the CO 2 electrode favoring the H + analyte SEN[CO 2 ][CO 2 ]=sensitivity of the CO 2 electrode favoring the CO 2 analyte f=final measurement i=initial measurement

Claim 21

An apparatus of combined pH and carbon dioxide electrochemical sensors for measuring the pH and the partial pressure of carbon dioxide in fluids, comprising: a) nonconducting substrate suitable for carrying printed wiring circuits, b) a pH electrode mounted on the substrate for electrical connection to an external lead from the substrate and positioned to contact sample fluid, wherein the electrode has a gas permeable hydrophobic ion selective polymeric membrane of high molecular weight polymer selected from the group consisting of: poly(vinylchloride), poly(bisphenol-A carbonate), cellulose acetate, poly(methylmethacrylate), poly(vinylidene chloride), polystyrene, polyurethane, block copolymers of polysiloxane/poly(bisphenol-A carbonate), polymers and copolymers of lower alkyl acrylate and methacrylate, silicone rubber with ionophores of trioctylamine and an aqueous dielectric with a pH in the range of up to around 5; c) a carbon dioxide electrode mounted on the substrate for electrical connection to an external lead from the substrate and in spaced apart relation to the pH electrode and positioned to contact sample fluid, wherein the carbon dioxide electrode has an lower molecular weight gas permeable polymeric ion selective membrane selected from the group consisting of: poly(vinylchloride), poly(bisphenol-A carbonate), cellulose acetate, poly(methylmethacrylate), poly(vinylidene chloride), polystyrene, polyurethane, block copolymers of polysiloxane/poly(bisphenol-A carbonate), polymers and copolymers of lower alkyl acrylate and methacrylate, silicone rubber with ionophores of trioctylamine and an aqueous dielectric with a pH in the range of at greater than 7 to 14, and the difference in the pH between the electrolytes is at least 0.1, and wherein both electrodes give some electronic response for both analytes; d) reference electrode mounted on the substrate for electrical connection to an external lead form the substrate and in spaced apart relation to the pH and carbon dioxide electrodes and positioned to contact the sample fluid and electrically connected to the pH and carbon dioxide electrodes; (for each of or common to the electrodes) e) electric circuitry on the substrate to electrically connect the electrodes to an external lead from the substrate for conveyance of electrical potentials and for electrical connection of the reference electrode to the pH and carbon dioxide electrodes; f) fluid circuit filled with a fluid selected from the group consisting of storage fluid, hydrating fluid, calibrating fluid and sample fluid and mixtures of these, wherein with such mixtures the sample fluid is in contact with the analyte electrodes where the fluid circuit is in liquid contact with the first, second and reference electrodes and insulated from the electric circuitry of the substrate; and g) programmed computer means having the functions of analog input processing, analog to digital conversion, programmed microprocessing, and a date/time circuit and battery backup random access memory, and a power supply electrically connected to the external leads of the substrate to receive the electrical potentials form the electrodes and to calculate the numerical values from simultaneous equations as follows: delta mVCO.sub.2 =-(SEN[CO.sub.2 ][pH])(de.sub.l.sbsb.t a pH)-(SEN [CO.sub.2 ][CO.sub.2 ])(log CO.sub.2 f/CO.sub.2 i) delta mVpH=-(SEN[pH][pH])(delta pH)-(SEN[pH][CO.sub.2 ])(log CO.sub.2 f/CO.sub.2 i) so that upon measuring the calibration fluid for known values of pH and CO2: ##EQU5## where: delta pH=change in pH delta mV=change in millivolts SEN [pH][CO 2 ]=sensitivity of the pH electrode favoring the CO 2 analyte SEN[pH][pH]=sensitivity of the pH electrode favoring H + analyte for the second analyte SEN[CO 2 ][pH]=sensitivity of the CO 2 electrode favoring the H + analyte SEN[CO 2 ][CO 2 ]=sensitivity of the CO 2 electrode favoring the CO 2 analyte f=final measurement i=initial measurement