US4201646A
Expired / Lapsed
US
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Apparatus for stripping voltammetry
Assignee: Magellan Diagnostics Inc
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Filing: 1977-11-30
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Granted: 1980-05-06
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Expires: 1997-11-30
Abstract
Abstract A system is disclosed for voltammetry such as anodic stripping voltammetry including a special electrode mounted to be fitted into a sample holder, stirring means operable through the electrode and an electrolytic potential source, optionally pulsed, capable of scanning the operating potential range which may for example, be a range between about -1 volt and 0 volt. Output recording means can be either an analog chart output or digitalized output. The system may be employed for a wide variety of test purposes generally relating to identifying and measuring heavy metals, one of which is detecting and measuring trace mineral components or trace elements in samples of human blood. When employed with blood samples the sample may first be prepared in the usual manner including digesting the sample but the presently preferred procedure contemplates that the metals being tested are first displaced from blood complexing with suitable ion such as Cr 3+ or Ca 2+ and the operating potential from about -800 millivolts to nearly 0 volt is scanned to read out the presence and quantity of metal such as lead, cadmium, copper and the like. An analysis of such metals can be run in as little as a minute. The ratio of electrode area to sample volume disclosed is 4cm 2 per 1.0 milliliter. A self contained test composition is disclosed.
Inventors
- 👤 Wayne R. Matson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:05
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/42; G01N27/48
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
145 words
An electrode assembly for stripping voltammetry analysis of a sample solution, and comprising in combination: an enclosure for holding a volume of said sample solution, a counter electrode located in said enclosure for contacting said sample solution; a working electrode located in said enclosure for contacting said sample solution, said working electrode being in the form of an axially hollow electrode body having a metal active electrode surface formed on the interior surface thereof; and rotatable stirring means (i) extending into the hollow of said electrode body, closely spaced (a) from the interior surface of said hollow and (b) from said counter electrode, and (ii) adapted to produce flow of said sample solution across said active electrode surface, said electrode assembly being dimensioned so that the ratio of surface area of said active electrode surface to sample volume is at least 3 cm 2 /ml.
Claim 2
Dependent Claim
145 words
An electrode assembly for stripping voltammetry analysis of a sample solution, and comprising in combination: an enclosure for holding a volume of said sample solution, a counter electrode located in said enclosure for contacting said sample solution; a working electrode located in said enclosure for contacting said sample solution, said working electrode being in the form of an axially hollow electrode body having a metal active electrode surface formed on the interior surface thereof; and rotatable stirring means (i) extending into the hollow of said electrode body, closely spaced (a) from the interior surface of said hollow and (b) from said counter electrode, and (ii) adapted to produce flow of said sample solution across said active electrode surface, said electrode assembly being dimensioned so that the ratio of surface area of said active electrode surface to sample volume is at least 3 cm 2 /ml.
Claim 3
Dependent Claim
16 words
An electrode combination according to claim 1, wherein said working electrode comprises a hollow graphite body.
Claim 4
Dependent Claim
37 words
An electrode combination according to claim 2, wherein said hollow graphite body has an active electrode surface in the form of a multiplicity of islands of mercury formed on the interior surface of said hollow graphite body.
Claim 5
Dependent Claim
36 words
An electrode combination according to claim 3 wherein said hollow electrode body comprises a wax impregnated hollow graphite cylinder, and said islands of mercury are deposited on graphite points surrounded by a portion of said wax.
Claim 6
Dependent Claim
24 words
An electrode combination according to claim 3 wherein said active electrode surface is also formed on the exterior surface of said hollow graphite body.
Claim 7
Dependent Claim
163 words
In Apparatus for use in electrochemically testing a sample solution by stripping voltammetry, in which ions present in a volume of said sample are first deposited on a working electrode in contact with said sample solution by applying a first potential on said working electrode, and thereafter the potential on said working electrode is varied so as to strip the deposited ions from said working electrode back into solution, and including an enclosure for holding a quantity of said solution for testing, the improvement wherein (A) said working electrode comprises an axially hollow cylindrical body (i) formed of an electrically insulating material and (ii) having an active electrode surface covering the interior surface of said hollow body at least in part, (B) rotatable stirring means extending into the hollow of said electrode body and closely spaced from said electrode active surface; and (C) the ratio of surface area of said active electrode surface to sample volume is at least 3 cm 2 /ml.
Claim 8
Dependent Claim
163 words
In Apparatus for use in electrochemically testing a sample solution by stripping voltammetry, in which ions present in a volume of said sample are first deposited on a working electrode in contact with said sample solution by applying a first potential on said working electrode, and thereafter the potential on said working electrode is varied so as to strip the deposited ions from said working electrode back into solution, and including an enclosure for holding a quantity of said solution for testing, the improvement wherein (A) said working electrode comprises an axially hollow cylindrical body (i) formed of an electrically insulating material and (ii) having an active electrode surface covering the interior surface of said hollow body at least in part, (B) rotatable stirring means extending into the hollow of said electrode body and closely spaced from said electrode active surface; and (C) the ratio of surface area of said active electrode surface to sample volume is at least 3 cm 2 /ml.
Claim 9
Dependent Claim
16 words
In apparatus according to claim 6, wherein said ratio is at least 4 cm 2 /ml.
Claim 10
Dependent Claim
24 words
In Apparatus according to claim 6, wherein said active electrode surface also covers the exterior surface of said hollow body at least in part.
Claim 11
Dependent Claim
28 words
In apparatus according to claim 6, wherein said rotatable stirring means is adapted to cause localized currents of said sample solution to flow across said active electrode surface.
Claim 12
Dependent Claim
19 words
In apparatus according to claim 6, wherein said hollow electrode body is dimensioned to fit snuggly within said enclosure.
Claim 13
Dependent Claim
74 words
In apparatus according to claim 6, wherein said rotatable stirring means comprises a propeller blade mounted on one end of a rotatably driven propeller shaft, and said propeller shaft is slightly tapered, being slightly larger at its lower end than it is at its upper end, whereby rotation of said propeller shaft and propeller produces a general flow of said sample solution downwards in the space between said stirrer and said active electrode surface.
Claim 14
Dependent Claim
65 words
In apparatus according to claim 6, and further including a counter electrode having an active electrode surface located in contact with said solution, a reference electrode having an active electrode surface located in contact with said solution, and means connecting (a) said counter electrode to a working potential, (b) said reference electrode to a reference potential, and (c) said working electrode to a working potential.
Claim 15
Dependent Claim
48 words
In apparatus according to claim 12 and further including a variable power supply and timer control adapted to first apply a positive potential to said working electrode for a period of time, and then to sweep down the potential on said working electrode over a period of time.
Claim 16
Dependent Claim
96 words
Apparatus according to claim 12 including: means to apply a first potential of a first polarity to said working electrode to cause deposition thereon of material corresponding to said ions being tested, means to pulse a staircase potential of opposite polarity to said working electrode to strip from said working electrode the ions deposited thereon by said first potential, said staircase potential spanning the stripping potential of said ions, means to measure and integrate the current flowing to said working electrode in said staircase potential, and means to display information corresponding to the integrated current flow.
Claim 17
Dependent Claim
49 words
Apparatus according to claim 14, wherein said working electrode active surface comprises a metal surface formed on the interior surface of said electrode hollow body, said active surface being electrically connected through said hollow body to said means to apply said first and said staircase potential to said electrode.
Claim 18
Dependent Claim
14 words
The apparatus of claim 15, wherein said electrode body comprises a hollow graphite body.
Claim 19
Dependent Claim
26 words
The apparatus of claim 16, wherein said active electrode surface comprises a multiplicity of islands of mercury formed on the interior surface of said hollow body.
Claim 20
Dependent Claim
48 words
In apparatus according to claim 12, and further including a variable power supply and timer control adapted to first apply a negative potential to said working electrode for a period of time, and then to sweep down the potential on said working electrode over a period of time.
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) | 1983-05-06 | 1983-11-05 | 1984-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-06 | 1987-11-05 | 1988-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-06 | 1991-11-05 | 1992-05-06 | $7700.00 | Window Closed / Lapsed |