US3920398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for chromatographic analysis of organic acids or their carboxylate salts
Assignee: Dow Chemical Co
•
Filing: 1973-08-06
•
Granted: 1975-11-18
•
Expires: 1993-08-06
Abstract
Abstract Apparatus and method for chromatographic quantitative analysis of a plurality of organic carboxylic acids or the carboxylate salts thereof in aqueous solution in the special circumstance wherein the said acids or salts occur substantially free of other ionic materials except for water soluble metal halide or hydroxide, or strong mineral acid. A sample of the solution is added to a first cation exchange resin bed in the silver ion form wherein any halide or hydroxide is precipitated and the sample is eluted therefrom with water to a second cation exchange resin bed in the hydrogen ion form wherein any carboxylate salts are converted to the free acids and the free acids present are chromatographically separated as elution with water proceeds. The effluent from the second column is directed to a conductivity cell where the separated ion species are quantitatively sensed as they pass through the cell.
Inventors
- 👤 Hamish Small
- 👤 Timothy S Stevens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:41
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/26; G01N30/38; G01N30/46; G01N30/461; B; B01; B01J; B01J39/00; B01J39/04; B01J39/05; B01J39/07; B01J39/26; G01N30/96; B01J2220/00; B01J2220/50; B01J2220/54; G01N2030/965; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/200833; Y10T436/201666
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
185 words
THE METHOD OF CHROMATOGRAPHIC QUANTITATIVE ANALYSIS OF A PLURALITY OF ORGANIC CARBOXLYIC ACIDS OR THE CARBOXYLATE SALTS THEREOF PRESENT IN AQUEOUS SAMPLE SOLUTION SUBSTANTIALLY FREE IONIC SPECIES OTHER THAN SAID ORGANIC ACIDS OR SALTS THEREOF, WATER SOLUBLE METAL HALIDE, SOLUBLE METAL HYDROXIDE, OR STRONG MINERAL ACID, WHICH COMPRISES: ADDING A PREDETERMINED AMOUNT OF SAID SAMPLE SOLUTION TO A CATION EXCHANGE RESIN BED MEANS, SAID MEANS BEING CHARGED WITH A CATION EXCHANGE RESIN IN THE SILVER FORM, AND ELUTING SAID SAMPLE FROM SAID FIRST CATION EXCHANGE RESIN BED MEANS WITH WATER THEREBY PRECIPITATING THE HALIDES PRESENT AS SILVER HALIDE AND CAPTURING, AT THE ION EXCHANGE SITES, ANY COUNTERVALENT SOLUBLE METAL IONS, AND HYDRONIUM IONS, PASSING THE ELFFFLUENT FROM THE FIRST CATION EXCHANGE RESIN BED MEANS THROUGH A SECOND CATION EXCHANGE RESIN BED MEANS, SAID SECOND RESIN BED MEANS BEING CHARGED WITH A CATION EXCHANGE RESIN IN THE ACID FORM THEREBY BRINGING ABOUT CHROMATOGRAPHIC SEPARATION OF THE ORGANIC CARBOXYLIC ACIDS OR THE RESPECTIVE CARBOXYLIC ACIDS PRODUCED FROM SAID CARBOXYLATE SALTS; AND PASSING THE EFFLUENT FROM SECOND CATION EXCHANGE RESIN BED MEANS CONTAINING SUBSTANTIALLY ONLY AQUEOUS OF CAR-
Claim 2
Independent Claim
185 words
THE METHOD OF CHROMATOGRAPHIC QUANTITATIVE ANALYSIS OF A PLURALITY OF ORGANIC CARBOXLYIC ACIDS OR THE CARBOXYLATE SALTS THEREOF PRESENT IN AQUEOUS SAMPLE SOLUTION SUBSTANTIALLY FREE IONIC SPECIES OTHER THAN SAID ORGANIC ACIDS OR SALTS THEREOF, WATER SOLUBLE METAL HALIDE, SOLUBLE METAL HYDROXIDE, OR STRONG MINERAL ACID, WHICH COMPRISES: ADDING A PREDETERMINED AMOUNT OF SAID SAMPLE SOLUTION TO A CATION EXCHANGE RESIN BED MEANS, SAID MEANS BEING CHARGED WITH A CATION EXCHANGE RESIN IN THE SILVER FORM, AND ELUTING SAID SAMPLE FROM SAID FIRST CATION EXCHANGE RESIN BED MEANS WITH WATER THEREBY PRECIPITATING THE HALIDES PRESENT AS SILVER HALIDE AND CAPTURING, AT THE ION EXCHANGE SITES, ANY COUNTERVALENT SOLUBLE METAL IONS, AND HYDRONIUM IONS, PASSING THE ELFFFLUENT FROM THE FIRST CATION EXCHANGE RESIN BED MEANS THROUGH A SECOND CATION EXCHANGE RESIN BED MEANS, SAID SECOND RESIN BED MEANS BEING CHARGED WITH A CATION EXCHANGE RESIN IN THE ACID FORM THEREBY BRINGING ABOUT CHROMATOGRAPHIC SEPARATION OF THE ORGANIC CARBOXYLIC ACIDS OR THE RESPECTIVE CARBOXYLIC ACIDS PRODUCED FROM SAID CARBOXYLATE SALTS; AND PASSING THE EFFLUENT FROM SECOND CATION EXCHANGE RESIN BED MEANS CONTAINING SUBSTANTIALLY ONLY AQUEOUS OF CAR-
Claim 3
Dependent Claim
29 words
The method as in claim 1 in which the organic carboxylic acids or their carboxylate salts are non-aromatic compounds having no more than 10 carbon atoms in the molecule.
Claim 4
Dependent Claim
44 words
The method as in claim 2 in which the organic carboxylic acids or the carboxylate salts thereof include any of fatty acids, hydroxy fatty acids, dicarboxylic acids, hydroxy dicarboxylic acids, hydroxy tricarboxylic acids and the carboxylate salts of any such acids and mixtures thereof.
Claim 5
Dependent Claim
33 words
The method as in claim 1 in which the total concentration of organic carboxylic acids or their carboxylate salts present in the aqueous sample solution is below about 5 per cent by weight.
Claim 6
Dependent Claim
38 words
The method as in claim 1 in which at least one of the organic carboxylic acids or the carboxylate salts thereof is present in the aqueous sample solution at a concentration below about 0.1 per cent by weight.
Claim 7
Dependent Claim
50 words
The method as in claim 1 wherein the cation exchange resin is sulfonated copolymer of styrene and divinylbenzene containing about 1 to 8 per cent by weight divinylbenzene and the balance styrene and is homogeneously sulfonated throughout the resin at at least 10 per cent of the available sulfonable sites.
Claim 8
Dependent Claim
54 words
The method as in claim 1 wherein the cation exchange resin in the second resin bed means has a specific exchange capacity in the range about 0.005 to 0.5 milliequivalents per gram, the predetermined amount of sample solution being less than that which would overload said resin in said cation exchange resin bed means.
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) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |