Chemical sensing apparatus and methods
First Claim
1. Amperometric sensing apparatus for detecting an analyte in a gaseous medium, winch comprises:
- a working electrode at which said analyte is caused to participate in an analyte half-cell reaction;
a reference electrode for controlling the electrochemical potential of said working electrode;
a counter electrode at which a complementary half-cell reaction is caused to occur, wherein all three electrodes are electrochemically connected through an electrolyte and said counter and reference electrodes may be combined into a single electrode;
means of enhancing the reactivity of the counter electrode to the product of the analyte reaction; and
means for reconverting the product of the analyte reaction back to the analyte and then reacting it again at the working electrode, with such back-and-forth reactions repeating many times, so as to yield an amplification of the analyte signal.
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Accused Products
Abstract
In an improved amperometric gas sensor, the structure, composition, and electrode potential are adjusted so as to prevent or minimize any unwanted reactivity at the counter and/or reference electrode of any analyte or interfering component of the matrix that may cross over thereto. The sensor is preferably structured so that the product of the analyte reaction at a first working electrode can be reconverted to the original analyte at a counter electrode or at a second working electrode and then reacted again at the first working electrode, with such back-and-forth reactions repeating many times, so as to yield an amplification of the analyte signal.
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Citations
16 Claims
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1. Amperometric sensing apparatus for detecting an analyte in a gaseous medium, winch comprises:
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a working electrode at which said analyte is caused to participate in an analyte half-cell reaction;
a reference electrode for controlling the electrochemical potential of said working electrode;
a counter electrode at which a complementary half-cell reaction is caused to occur, wherein all three electrodes are electrochemically connected through an electrolyte and said counter and reference electrodes may be combined into a single electrode;
means of enhancing the reactivity of the counter electrode to the product of the analyte reaction; and
means for reconverting the product of the analyte reaction back to the analyte and then reacting it again at the working electrode, with such back-and-forth reactions repeating many times, so as to yield an amplification of the analyte signal. - View Dependent Claims (2, 3, 4)
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5. Amperometric sensing apparatus for detecting an analyte in a gaseous medium, which comprises:
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a first working electrode at which said analyte is caused to participate in an analyte half-cell reaction; and
a second working electrode for reconverting tho product of the analyte reaction back to the analyte; and
means for reacting said product again at the first working electrode, with such back-and-forth reactions repeating many times, so as to yield an amplification of the analyte signal, each of said working electrodes being electrochemically connected to its respective pair of counter and reference electrodes;
wherein each of said pairs of counter and reference electrodes may be combined into a single electrode. - View Dependent Claims (6, 7)
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8. A method of detecting the presence of an analyte or trace thereof in a gaseous medium comprising the steps of:
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passing a sample of said gaseous medium over a pair of interdigitated electrodes forming part of an amperometric gas sensor system, while applying an oxidizing potential to one electrode of said pair and a reducing potential to the other electrode of said pair, so as to cause repeated oxidations and reductions of said analyte and of its redox product and thereby produce amplified current signals due to said analyte and product;
measuring said amplified current signals; and
deducing the presence or identity or concentration of said analyte in said gaseous medium from said measured current signals. - View Dependent Claims (9)
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10. Sensing apparatus for detecting an analyte in a gaseous medium, which comprises:
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means for passing a sample of said gaseous medium over a pair of interdigitated electrodes forming part of an amperometric gas sensor system, while applying an oxidizing potential to one electrode of said pair and a reducing potential to the other electrode of said pair, so as to cause repeated oxidations and reductions of said analyte and of its redox product and thereby produce amplified current signals due to said analyte and product; and
means for measuring said amplified current signals. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification