Electrochemical detection of carbon dioxide
First Claim
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1. An electrochemical cell for detecting the presence of at least one member of a class of species consisting of CO2, O2, and H2 O as the species of interest in a liquid or gaseous sample mixture which may contain CO2, O2 and H2 O comprising:
- a hollow chamber having an opening therein in communication with the sample which may contain the species of interest;
a barrier membrane of polymeric material impervious to liquids but permeable to CO2, O2 and H2 O vapor covering said opening and comprising at least one layer;
a substrate member disposed beneath said barrier of polymeric material;
a set of electrodes including reference, working and counter electrodes disposed on or supported from said substrate member;
a non-aqueous, aprotic, gelled electrolyte system permeable to CO2, O2 and H2 O in contact with said electrodes and further comprising a solvent mixture consisting of a high donor number solvent and a moderate donor number solvent, an amount of electrolyte salt and a compatible gelling agent; and
circuit means configured to apply desired potential differences between the working electrode and the reference electrode, said circuit means further including potential control means to modulate said desired potential differences on a time variable basis and including means to measure cell output based on the reduction of O2, H2 O and CO2.
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Abstract
An electrochemical system for the detection of carbon dioxide includes a single cell chamber exposed to the sample medium through a polymeric barrier membrane, a single set of electrodes and utilizes an aprotic non-aqueous, gelled solvent/electrolyte medium which allows measurement of CO2 in the presence of both oxygen and water vapor.
36 Citations
25 Claims
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1. An electrochemical cell for detecting the presence of at least one member of a class of species consisting of CO2, O2, and H2 O as the species of interest in a liquid or gaseous sample mixture which may contain CO2, O2 and H2 O comprising:
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a hollow chamber having an opening therein in communication with the sample which may contain the species of interest; a barrier membrane of polymeric material impervious to liquids but permeable to CO2, O2 and H2 O vapor covering said opening and comprising at least one layer; a substrate member disposed beneath said barrier of polymeric material; a set of electrodes including reference, working and counter electrodes disposed on or supported from said substrate member; a non-aqueous, aprotic, gelled electrolyte system permeable to CO2, O2 and H2 O in contact with said electrodes and further comprising a solvent mixture consisting of a high donor number solvent and a moderate donor number solvent, an amount of electrolyte salt and a compatible gelling agent; and circuit means configured to apply desired potential differences between the working electrode and the reference electrode, said circuit means further including potential control means to modulate said desired potential differences on a time variable basis and including means to measure cell output based on the reduction of O2, H2 O and CO2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An electrochemical cell for detecting the presence of one or both of CO2 and O2 in a liquid sample mixture which may contain CO2, O2 and H2 O comprising;
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a hollow chamber having an opening therein in communication with the sample which may contain the species of interest; a barrier membrane of polymeric material impervious to liquids but permeable to CO2 and O2 covering said opening and comprising a plurality of separate spaced members; means for containing a liquid sample external to said chamber and in contact with said barrier membrane; a substrate member disposed beneath said barrier of polymeric material; a single set of electrodes including reference, working and counter electrodes disposed on or supported from said substrate member; a non-aqueous, aprotic, gelled electrolyte system permeable to CO2 and O2 in contact with said electrodes and further comprising a solvent mixture consisting of a high donor number solvent and a moderate donor number solvent, an amount of electrolyte salt and a compatible gelling agent; and circuit means configured to apply desired potential differences between the working electrode and the reference electrode, said circuit means further including potential control means to modulate said desired potential differences on a time variable basis, and including means to measure cell output based on the reduction of O2 and CO2. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method for detecting the presence of at least one species of interest of a class consisting of CO2, O2 and H2 O in a liquid or gaseous sample mixture containing at least one other of said species comprising the steps of:
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causing the species of said class contained in the sample to be transported across from an outer surface to an inner surface of a barrier membrane impervious to liquids but permeable to CO2, O2 and H2 O vapor, into a cell means, said cell means comprising, a set of electrodes including reference, working and counter electrodes disposed beneath said barrier, a non-aqueous, aprotic, gelled electrolyte system permeable to CO2, O2 and H2 O in contact with said electrodes and further comprising a solvent mixture consisting of a high donor number solvent and a moderate donor number solvent, and an amount of electrolyte salt and a compatible gelling agent; determining the presence of each of said species of interest by applying a time variable potential difference between the working electrode and the reference electrode which sequentially applies sufficient potential to reduce each such species of interest in increasing order; and measuring cell output based on the reduction of each of O2, H2 O and CO2. - View Dependent Claims (21, 22, 23)
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24. An electrochemical cell for detecting the presence of at least one member of a class of species of interest in a liquid or gaseous sample mixture which may contain one or more of such species of interest said class consisting of plurality of gaseous species each having a distinct oxidation or reduction potential within the operating range of the potential of said cell comprising:
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a hollow chamber having an opening therein in communication with the sample which may contain the species of interest; a barrier membrane of polymeric material impervious to liquids but permeable to the species of interest in gaseous form covering said opening and comprising at least one layer; a set of three electrodes including reference, working and counter electrodes disposed beneath said barrier membrane and in predetermined spaced relation thereto and to each other; a non-aqueous, aprotic, gelled electrolyte system permeable to the species of interest in contact with said electrodes and further comprising a solvent mixture consisting of a high donor number solvent and a moderate donor number solvent, an amount of electrolyte salt and a compatible gelling agent; and circuit means configured to apply desired potential differences between the working electrode and the reference electrode, said circuit means further including potential control means to modulate said desired potential differences on a time variable basis and including means to measure cell output based on the oxidation or reduction in ascending potential order of each species of interest. - View Dependent Claims (25)
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Specification