US5266496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Headspace analysis
Assignee: Individual
•
Filing: 1992-04-10
•
Granted: 1993-11-30
•
Expires: 2012-04-10
Abstract
Abstract A process for extracting and analyzing virtually any sample which may be contaminated with pollutants, toxics or other impurities. The process can be used to extract and analyze one contaminant, such as a volatile compound (gasoline), or the process can be used to extract and analyze several contaminants, including both volatiles and semi-volatiles. The process comprises a vacuum extraction technique followed by a heating/cooling cycle comprising a series of heating and cooling stages.
Inventors
- 👤 Amelia L. Dacruz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:03
CPC Classifications
G; G01; G01N; G01N1/00; G01N1/28; G01N1/40; G01N25/00; G01N25/14; G01N33/00; G01N33/18; G01N33/1826; Y; Y10; Y10T; Y10T436/00; Y10T436/23; Y10T436/235
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
171 words
A process for extracting and analyzing a sample containing at least one volatile contaminant, comprising the following steps: (a) placing a sample in an extraction vessel and sealing the vessel; (b) applying a vacuum of 25 mmHg equivalent over the extraction vessel thereby creating a headspace above the sample; (c) agitating the sample and extraction vessel; (d) subjecting the sample to at least one heating and cooling cycle, wherein said cycle comprises a first heating stage followed by a cooling stage, wherein in said cooling stage, aqueous vapors in the headspace are converted to the liquid state while the volatile contaminant vapors remain in the gaseous state, thereby preventing the complexing of the gaseous contaminants with the aqueous vapors, and wherein after said at least one heating and cooling cycle is conducted, subjecting the sample to a final heating stage; and (e) withdrawing a sample gas aliquot from the headspace and injecting said sample into a gas chromatography column for analysis, wherein said withdrawal occurs only after the final heating stage.
Claim 2
Dependent Claim
171 words
A process for extracting and analyzing a sample containing at least one volatile contaminant, comprising the following steps: (a) placing a sample in an extraction vessel and sealing the vessel; (b) applying a vacuum of 25 mmHg equivalent over the extraction vessel thereby creating a headspace above the sample; (c) agitating the sample and extraction vessel; (d) subjecting the sample to at least one heating and cooling cycle, wherein said cycle comprises a first heating stage followed by a cooling stage, wherein in said cooling stage, aqueous vapors in the headspace are converted to the liquid state while the volatile contaminant vapors remain in the gaseous state, thereby preventing the complexing of the gaseous contaminants with the aqueous vapors, and wherein after said at least one heating and cooling cycle is conducted, subjecting the sample to a final heating stage; and (e) withdrawing a sample gas aliquot from the headspace and injecting said sample into a gas chromatography column for analysis, wherein said withdrawal occurs only after the final heating stage.
Claim 3
Dependent Claim
13 words
The process according to claim 1, wherein the sample is a liquid sample.
Claim 4
Dependent Claim
25 words
The process according to claim 2, wherein the liquid sample is selected from the group consisting of ground water, waste water, effluents, and surface waters.
Claim 5
Dependent Claim
13 words
The process according to claim 1, wherein the sample is a solid sample.
Claim 6
Dependent Claim
21 words
The process according to claim 4, wherein the solid sample is selected from the group consisting of soil, wood and rock.
Claim 7
Dependent Claim
22 words
The process according to claim 1, wherein the sample is selected from the group consisting of mud, sludges, emulsion, suspensions and dispersions.
Claim 8
Dependent Claim
14 words
The process according to claim 1, wherein the sample is contaminated with petroleum by-products.
Claim 9
Dependent Claim
17 words
The process according to claim 7, wherein the sample is contaminated by gasoline, diesel, and mixtures thereof.
Claim 10
Dependent Claim
33 words
The process according to claim 1 wherein the sample is contaminated with one or more substances selected from the group consisting of pesticides, herbicides, polychlorinated biphenyls (pcbs), phenols, phthalate esters and hydrophobic solvents.
Claim 11
Dependent Claim
22 words
The process according to claim 1 further comprising the step of storing and preserving the sample after the vacuum extraction step (b).
Claim 12
Dependent Claim
18 words
The process according to claim 1, wherein the sample is initially chilled to a temperature of 4° C.
Claim 13
Dependent Claim
19 words
The process according to claim 11, wherein the extraction vessel is chilled to the same temperature as the sample.
Claim 14
Dependent Claim
33 words
The process according to claim 1, wherein the sample is chilled and diluted with chilled deionized water to bring the sample to a volume of 25 ml before placement in the extraction vessel.
Claim 15
Dependent Claim
15 words
The process according to claim 1, wherein the process comprises one heating and cooling cycle.
Claim 16
Dependent Claim
25 words
The process according to claim 14, wherein each temperature stage is independently conducted for an interval of from about 2 minutes to about 15 minutes.
Claim 17
Dependent Claim
14 words
The process according to claim 15, wherein each interval is conducted for ten minutes.
Claim 18
Dependent Claim
15 words
The process according to claim 14 wherein the process comprises two heating and cooling cycles.
Claim 19
Dependent Claim
23 words
The process according to claim 17, wherein each heating stage is conducted at a temperature of from about 150° to about 200° C.
Claim 20
Dependent Claim
19 words
The process according to claim 18, wherein each heating stage is conducted at a temperature of about 180° C.
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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) | 1996-11-29 | 1997-05-31 | 1997-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-29 | 2001-05-31 | 2001-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-29 | 2005-05-31 | 2005-11-30 | $7700.00 | Window Closed / Lapsed |