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US4066528A
Expired / Lapsed
US
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Analytical apparatus
Assignee: Imperial Chemical Industries Ltd
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Filing: 1976-07-19
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Granted: 1978-01-03
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Expires: 1996-07-19
Abstract
Abstract Apparatus for coulometry comprises (a) an instrumentation amplifier acting as a differential to single-ended potential convertor having high input impedence, (b) means for feeding (a) with the potential between the sensor and reference electrodes of a coulometric cell and (c) and differential potential input amplifier fed by (a) and by means for setting the output of (c) to zero, the phase shift of the apparatus being less than 90°.
Inventors
- 👤 John Rickard Mansfield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:21
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/42
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
126 words
Apparatus for carrying out coulometric analysis which comprises: a. an instrumentation amplifier which acts as a differential to single ended potential convertor having a high input impedance, b. a coulometric cell having a sensor electrode, a reference electrode, and a generator electrode and means for feeding (a) with the potential between the sensor and reference electrodes of said coulometric cell, c. a differential potential input amplifier fed by (a) and by means for setting the output current of (c) to zero at a desired potential difference between the sensor and reference electrodes by feeding a suitable offset potential to (c), the whole apparatus excluding the coulometric cell having a phase shift of less than 90° and responding to direct or low frequency electromotive force input signals.
Claim 2
Dependent Claim
126 words
Apparatus for carrying out coulometric analysis which comprises: a. an instrumentation amplifier which acts as a differential to single ended potential convertor having a high input impedance, b. a coulometric cell having a sensor electrode, a reference electrode, and a generator electrode and means for feeding (a) with the potential between the sensor and reference electrodes of said coulometric cell, c. a differential potential input amplifier fed by (a) and by means for setting the output current of (c) to zero at a desired potential difference between the sensor and reference electrodes by feeding a suitable offset potential to (c), the whole apparatus excluding the coulometric cell having a phase shift of less than 90° and responding to direct or low frequency electromotive force input signals.
Claim 3
Dependent Claim
40 words
Apparatus as claimed in claim 1 in which the means for setting the output of (c) to zero at a desired potential difference between the sensor and reference electrodes by feeding a suitable offset potential to (c) comprises a potentiometer.
Claim 4
Dependent Claim
22 words
Apparatus as claimed in claim 1 which further comprises means for holding an electrolyte and means to introduce sample to the electrolyte.
Claim 5
Dependent Claim
35 words
Apparatus as claimed in claim 3 in which the coulometric cell further comprises an auxiliary electrode in electrolytic communication with the electrolyte and adapted to prevent species generated at it from reaching the generator electrode.
Claim 6
Dependent Claim
41 words
Apparatus as claimed in claim 1 in which the current passing to the generator electrode is recorded by a high input impedence potentiometric recorder which is in parallel with a variable resistance through which current to the generator electrode is fed.
Claim 7
Dependent Claim
64 words
Apparatus as claimed in claim 1 in which a switch is provided to connect the output of the differential potential input amplifier (c) to earth through a meter to enable the system to be nulled for a given electrode potential in order to avoid generation of a species capable of consuming the material to be determined during a nulling operation prior to the analysis.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |