US3635679A
Expired / Lapsed
US
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Metal ion detecting membrane
Assignee: Bayer Corp
•
Filing: 1969-11-20
•
Granted: 1972-01-18
•
Expires: 1989-11-20
Abstract
Abstract Metal ions can be determined colorimetrically by using a semipermeable polymeric membrane containing a chelating agent and a solvent therefor, which chelating agent changes color upon contact with the metal ions being determined.
Inventors
- 👤 Rene Bloch
- 👤 Robert Bauer
- 👤 Ben F Phillips
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:55
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
12 words
A membrane as in claim 1 wherein said solvent is a plasticizer.
Claim 2
Dependent Claim
44 words
A membrane according to claim 1 wherein the metal ions are selected from the group consisting of iron, cobalt, nickel, copper, lead and mercury and the chelating agent is selected from the group consisting of thenoyltrifluoroacetone, diphenylthiocarbazone, gallocyanine, dimethylglyoxime and ethylene glycol tetraacetic acid.
Claim 3
Dependent Claim
26 words
A membrane according to claim 1 wherein the semipermeable polymeric matrix is selected from the group consisting of ethyl cellulose, polyvinyl chloride, cellulose acetate and collodion.
Claim 4
Dependent Claim
35 words
A membrane according to claim 2 wherein the plasticizer is selected from the group consisting of tributyl phosphate, tricresyl phosphate, dibutyl adipate, dibutyl sebacate, diisobutyl azelate, dibutyl phthalate, dipentyl phthalate, triethyl citrate and glyceryl tripropionate.
Claim 5
Dependent Claim
37 words
A method for determining polyvalent metal ions in solution which comprises contacting a membrane according to claim 1 with a solution containing the polyvalent metal ions being determined and observing any resulting color change in said membrane.
Claim 6
Dependent Claim
22 words
A method according to claim 6 wherein the color resulting from said color change is compared with a previously prepared color chart.
Claim 7
Dependent Claim
21 words
A method according to claim 6 wherein the color resulting from said color change is observed by means of a spectrophotometer.
Claim 8
Dependent Claim
11 words
A membrane as in claim 1 which additionally contains a plasticizer.
References Cited (Backward Citations)
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Cited
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Cited
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |