US4059406A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrochemical detector system
Assignee: E D T Supplies Ltd
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Filing: 1976-07-12
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Granted: 1977-11-22
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Expires: 1996-07-12
Abstract
Abstract An electrochemical detector has an electrochemical thin-layer flow cell whose operation is based on the so-called wall-jet principle, in combination with a controller unit. The controller unit can apply a periodically changing voltage having a square wave voltage formation to a sensor electrode of the electrochemical cell such that a first potential level of the square wave functions as a detecting potential and a second potential level of the square wave functions as a cleaning potential.
Inventors
- 👤 Bernard Fleet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:57
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/28; G01N27/30; G01N27/38; G01N27/416; G01N27/42; G01N30/00; G01N30/02; G01N30/62; G01N30/64
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
117 words
A method for detecting an electroactive species in a flow stream comprising the steps of: i. forcing a solution containing the electroactive species through a fine nozzle to form a jet, ii. impringing the jet normally to a surface of a sensor electrode so that the solution spreads radially over the surface in a thin film, iii. applying a periodically changing voltage to the sensor electrode, so that one part of each cycle of the applied voltage functions as a detecting potential and another part of each cycle functions as a cleaning potential, and iv. measuring a current at the sensor electrode during that part of each cycle of the applied voltage functioning as a detecting potential.
Claim 2
Independent Claim
117 words
A method for detecting an electroactive species in a flow stream comprising the steps of: i. forcing a solution containing the electroactive species through a fine nozzle to form a jet, ii. impringing the jet normally to a surface of a sensor electrode so that the solution spreads radially over the surface in a thin film, iii. applying a periodically changing voltage to the sensor electrode, so that one part of each cycle of the applied voltage functions as a detecting potential and another part of each cycle functions as a cleaning potential, and iv. measuring a current at the sensor electrode during that part of each cycle of the applied voltage functioning as a detecting potential.
Claim 3
Dependent Claim
26 words
A method for detecting an electroactive species as claimed in claim 1 comprising the further step of: v. recording the current measured at the sensor electrode.
Claim 4
Dependent Claim
52 words
A method for detecting an electroactive species as claimed in claim 1 which consists of applying a square wave voltage to the sensor electrode, a first level of each cycle of the applied square wave functioning as a detecting potential and a second level of each cycle functioning as a cleaning potential.
Claim 5
Dependent Claim
89 words
In an electrochemical detector having an electrochemical thin-layer flow cell adapted to operate on the wall-jet principle comprising a solution inlet line terminating in a fine nozzle, a sensor electrode, at least one solution exit line, and at least one other electrode, the improvement comprising means for applying a periodically changing voltage to the sensor electrode so that a first part of each cycle of the applied voltage functions as a detecting potential and a second part of each cycle of the applied voltage functions as a cleaning potential.
Claim 6
Dependent Claim
89 words
In an electrochemical detector having an electrochemical thin-layer flow cell adapted to operate on the wall-jet principle comprising a solution inlet line terminating in a fine nozzle, a sensor electrode, at least one solution exit line, and at least one other electrode, the improvement comprising means for applying a periodically changing voltage to the sensor electrode so that a first part of each cycle of the applied voltage functions as a detecting potential and a second part of each cycle of the applied voltage functions as a cleaning potential.
Claim 7
Dependent Claim
21 words
The improvement claimed in claim 4 wherein the periodically changing voltage applied to the sensor electrode is a square wave voltage.
Claim 8
Dependent Claim
34 words
The improvement claimed in claim 5 wherein a first level of each square wave cycle functions as a detecting potential and a second level of each square wave cycle functions as a cleaning potential.
Claim 9
Dependent Claim
27 words
The improvement claimed in claim 6 wherein a current is measured for a short period towards the end of each level which functions as a detecting potential.
Claim 10
Dependent Claim
22 words
The improvement claimed in claim 7 wherein the short period is equal to the time required for one cycle of mains voltage.
Claim 11
Dependent Claim
17 words
The improvement claimed in claim 5 comprising means for altering the amplitude of the square wave voltage.
Claim 12
Dependent Claim
31 words
The improvement claimed in claim 6 comprising means for altering the frequency of the square wave voltage and the length of the said first and second level independently of each other.
Claim 13
Dependent Claim
103 words
An electrochemical detector having an electrochemical thin-layer flow cell adapted to operate on the wall-jet principle comprising a sensor electrode, a solution inlet line terminating in a fine nozzle, the said nozzle being located normally to but displaced from a surface of the sensor electrode, at least one solution exit line, at least one other electrode and means comprising a controller unit for applying a periodically changing voltage to the sensor electrode so that one part of each cycle of the applied voltage functions as a detecting potential and another part of each cycle of the applied voltage functions as a cleaning potential.
Claim 14
Dependent Claim
103 words
An electrochemical detector having an electrochemical thin-layer flow cell adapted to operate on the wall-jet principle comprising a sensor electrode, a solution inlet line terminating in a fine nozzle, the said nozzle being located normally to but displaced from a surface of the sensor electrode, at least one solution exit line, at least one other electrode and means comprising a controller unit for applying a periodically changing voltage to the sensor electrode so that one part of each cycle of the applied voltage functions as a detecting potential and another part of each cycle of the applied voltage functions as a cleaning potential.
Claim 15
Dependent Claim
25 words
An electrochemical detector as claimed in claim 11 comprising means for altering the distance between the fine nozzle and the surface of the sensor electrode.
Claim 16
Dependent Claim
35 words
An electrochemical detector as claimed in claim 11 wherein the said electrochemical cell has an effective cell volume in the range from less than 1 μl (10 -6 l) to 100 μl (10 -6 l).
Claim 17
Dependent Claim
21 words
An electrochemical detector as claimed in claim 11 wherein the sensor electrode surface is planar and the sensor electrode is disc-shaped.
Claim 18
Dependent Claim
16 words
An electrochemical detector as claimed in claim 11 wherein the sensor electrode is in ring form.
Claim 19
Dependent Claim
18 words
An electrochemical detector as claimed in claim 11 wherein the sensor electrode consists of high density vitreous carbon.
Claim 20
Dependent Claim
26 words
An electrochemical detector as claimed in claim 11 wherein the electrochemical thin-layer flow cell has one solution exit line, a reference electrode and a counter electrode.
Claim 21
Dependent Claim
40 words
An electrochemical detector as claimed in claim 11 in combination with a high performance, high pressure liquid chromatography column having duct means for an effluent from the said column to enter the solution inlet line of the said electrochemical cell.
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) | 1980-11-21 | 1981-05-23 | 1981-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-21 | 1985-05-23 | 1985-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-21 | 1989-05-23 | 1989-11-22 | $7700.00 | Window Closed / Lapsed |