Electrochemical detection system and method of analysis
First Claim
1. A flow cell for electrochemical testing a sample in solution, said cell comprising:
- a holder assembly having an inlet for directing a stream of said sample to be tested into said cell, and an outlet for directing tested sample from said cell;
a plurality of electrode elements arranged in a stack in said holder assembly and including at least one active testing electrode, at least one reference electrode, and at least one counter electrode, at least one of said active testing electrodes comprising a solid phase electrode in the form of a solid disk of electrically conductive material having at least one bore extending therethrough and having an active electrode surface located in said at least one bore, said plurality of electrodes being arranged in said stack so that said electrodes are electrically insulated from one another with their respective bores aligned so as to define at least one flow channel connecting said inlet and said outlet; and
,a flow restrictor formed of electrically conductive material located in the bore of at least one of said disks and electrically connected to said disk.
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Accused Products
Abstract
An electrochemical detection apparatus is provided. The apparatus comprises a flow-cell having at least one active testing electrode, at least one reference electrode, and at least one counter electrode. Each electrode comprises a liquid impervious solid body having a bore extending therethrough with the electrode active surface located in the bore. The electrodes are arranged in a stack, electrically insulated from one another with their respective bores aligned so as to define a flow channel through which liquid to be detected can be passed. In a preferred embodiment of the invention at least one of the reference electrodes is actively driven to supply a stable reference potential against which other electrochemical responses can be measured. Various electrochemical responses are achieved by varying the construction, number and arrangement of electrodes in the stack, and the potentials applied to the electrodes. The detection apparatus has particular utility for use in monitoring chromatographic eluant.
77 Citations
68 Claims
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1. A flow cell for electrochemical testing a sample in solution, said cell comprising:
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a holder assembly having an inlet for directing a stream of said sample to be tested into said cell, and an outlet for directing tested sample from said cell; a plurality of electrode elements arranged in a stack in said holder assembly and including at least one active testing electrode, at least one reference electrode, and at least one counter electrode, at least one of said active testing electrodes comprising a solid phase electrode in the form of a solid disk of electrically conductive material having at least one bore extending therethrough and having an active electrode surface located in said at least one bore, said plurality of electrodes being arranged in said stack so that said electrodes are electrically insulated from one another with their respective bores aligned so as to define at least one flow channel connecting said inlet and said outlet; and
,a flow restrictor formed of electrically conductive material located in the bore of at least one of said disks and electrically connected to said disk. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A flow cell for electrochemically testing a sample stream, said cell comprising in combination:
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a holder assembly having an inlet for directing said stress to be tested into said cell, and an outlet for directing tested sample from said cell; at least one reference electrode comprising a flat solid body mounted in said holder assembly, said body having (a) a pair of generally planar surfaces, (b) a bore extending therethrough between said planar surfaces, and (c) an active electrode surface located within said bore; at least one counter electrode comprising a flat solid body mounted in said holder assembly, said body having (a) a pair of generally planar surfaces, (b) a bore extending therethrough between said planar surfaces and (c) an active electrode surface located within said bore; at least one active testing electrode comprising a solid phase electrode in the form of a flat solid body mounted in said holder assembly, each of said bodies having (a) a pair of generally planar surfaces (b) a bore extending therethrough between said planar surfaces, (c) solid phase active electrode surface located within said bore; and
, (d) a plug of porous, electrically conductive material located in the bore of at least one of said bodies and electrically connected to said body;said at least one reference electrode, said at least one counter electrode, and said at least one active testing electrode being mounted in said holder assembly electrically insulated from one another with their respective bores aligned with one another so as to define a flow channel between said inlet and said outlet.
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28. An electrochemical testing apparatus for measuring a sample material in solution comprising:
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a flow cell having at least one flow path therethrough, an inlet for directing a stream containing said sample material to be tested into said cell, and an outlet for directing tested sample material from said cell; a plurality of electrodes including at least one solid phase testing electrode located in said at least one flow path, each of said electrodes having at least one bore extending therethrough and forming a boundary or boundaries for said at least one flow path, said electrodes being positioned in serial arrangement along said at least one flow path; a plug of porous, electrically conductive material located in the bore of at least one of said solid phase testing electrodes and electrically connected to said electrodes; and
,means connecting at least said at least one solid phase electrode to an active testing potential source;
means connecting at least one other of said electrodes to a reference potential source;
means connecting at least yet another of said electrodes to yet another potential source; and
, means coupled to said means for connecting for producing an electrical signal readout representative of current flow between selected of said electrodes. - View Dependent Claims (29, 30, 31, 32, 33)
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34. In a method of electrochemically analyzing a sample material to identify selected substances therein, the steps of:
- dissolving said sample material in a carrier therefor to form a test fluid, and passing a stream of said test fluid through an electrolytic flow cell in contact with a detection electrode,
the improvement wherein said flow cell comprises a plurality of electrode elements including at least one solid phase testing electrode arranged in a stack in a holder, each of said electrode elements in said stack comprising a solid body having at least one bore extending therethrough and an active electrode surface located in said at least one bore, said plurality of electrodes being arranged in said stack so that said electrodes are electrically insulated from one another with their respective bores aligned so as to define at least one flow channel for said stream, said flow cell having a plug of electrically conductive material located in the bore of at least one of said solid phase testing electrodes and electrically connected to said electrode, passing said stream through said at least one flow channel in contact with said active electrode surfaces, applying electrical potentials across said stream between selected of said electrodes in said stack, deriving electrical signals resulting on selected of said electrodes in said stack, and sorting said signals to obtain signals which identify said selected substances. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41)
- dissolving said sample material in a carrier therefor to form a test fluid, and passing a stream of said test fluid through an electrolytic flow cell in contact with a detection electrode,
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42. A flow cell for electrochemically testing a sample in solution, said cell comprising:
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a holder having an inlet for directing a stream of said sample to be tested into said cell, an outlet for directing tested sample from said cell, and a flow channel connecting said inlet and said outlet; a plurality of electrode elements including at least one solid phase testing electrode, at least one reference electrode and at least one counter electrode, arranged in a stack in said holder, at least one of said electrode elements in said stack comprising a solid, porous body having active electrode surfaces located in the pores of said body, at least one other of said electrode elements in said stack comprising a solid body having at least one bore extending therethrough and having a plug of porous, electrically conductive material having active electrode surfaces located in said bores, said bores and said pores being aligned so as to define said flow channel in part. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58)
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57. In a method of electrochemically analyzing a sample material to identify selected substances therein, the steps of:
- dissolving said sample material in a carrier therefor to form a test fluid and passing a stream of said test fluid through an electrolytic flow cell in contact with said detection electrode,
the improvement wherein said flow cell comprises a plurality of electrode elements including at least one solid phase testing electrode arranged in a stack in a holder, at least one of said electrode elements in said stack comprising a solid, porous having active electrode surfaces located in the pores of said, at least one other of said electrode elements in said stack comprising a solid body having at least one bore extending therethrough and having a plug of porous, electrically conductive material having an active electrode surface located in said at least one bore, said plurality of electrodes being arranged in said stack and electrically insulated from one another in said holder with said at least one bore and said pores being aligned so as to define at least one flow channel for said stream, applying electrical potentials across said stream between selected of said electrodes in said stack, deriving electrical signals resulting on selected of said electrodes in said stack, and sorting said signals to obtain signals which identify said selected substances. - View Dependent Claims (59, 60, 61, 62, 63, 64)
- dissolving said sample material in a carrier therefor to form a test fluid and passing a stream of said test fluid through an electrolytic flow cell in contact with said detection electrode,
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65. An electrochemical apparatus for testing a sample material in solution, said apparatus comprising, in combination:
an electrolytic cell for holding said sample to be tested, said electroyltic cell having a plurality of electrically discrete electrodes located therein, at least one of said plurality comprising a solid phase active testing electrode, at least one other of said plurality comprising a counter electrode, and at least one other of said electrodes comprising a reference electrode, wherein at least one of said electrodes selected from the group consisting of said active testing electrode and said counter electrode comprises a plug of porous, electrically conductive material, and said reference electrode comprises an inert metal or metal oxide terminal, and including means connecting said solid phase active testing electrode to an active testing potential source;
means connecting said at least one counter electrode to yet another potential source, and means connecting said at least one reference electrode to a feed back network and follower amplifier for applying a variable potential which is responsive to electrochemical changes in said sample.- View Dependent Claims (66)
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67. An electrochemical flow cell for testing a sample material in solution, said apparatus comprising, in combination:
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a holder assembly having an inlet for directing a stream of said sample to be tested into said cell, and an outlet for directing tested sample from said cell; a plurality of electrically discrete electrodes located in a stack in said holder assembly, said plurality including at least one solid phase active testing electrode, at least one counter electrode, and at least one reference electrode, at least one of said solid phase active testing electrodes in said stack comprising a solid body having at least one bore extending therethrough and defining in part a flow channel connecting said inlet and said outlet, a plug of porous, electrically conductive material located in said flow channel in said at least one bore, and including means connecting said at least one solid phase active testing electrode to an active testing potential source, means connecting said at least one counter electrode to yet another potential source, and means connecting said at least one reference electrode to a feed back network and follower amplifier for applying a variable potential which is responsive to electrochemical changes in said sample. - View Dependent Claims (68)
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Specification