Patent US5989997A successfully refreshed from Google Patents.
Patent US4080168A successfully refreshed from Google Patents.
US4080168A
Expired / Lapsed
US
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Method and apparatus for the wet digestion of organic and biological samples
Assignee: University of Missouri–St. Louis
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Filing: 1976-02-18
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Granted: 1978-03-21
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Expires: 1996-02-18
Abstract
Abstract A rapid, safe and efficient process for the digestion and destruction of organic matter in materials of biological origin. Acid mixtures (nitric and perchloric acids for ashing; appropriate acid mixtures for other digestions) are added to the sample and then heated internally by absorption of microwave energy from a precisely controlled field within a specially modified microwave oven.
Inventors
- 👤 Adel Abu-Samra
- 👤 Samuel R. Koirtyohann
- 👤 John S. Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:27
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/64; H05B6/80; Y; Y10; Y10T; Y10T436/00; Y10T436/25; Y10T436/25125
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
122 words
A method for the chemical digestion, prior to analysis, of organic samples comprising the steps of: providing a modified microwave oven formed with an acid fume resistant sample receiving box disposed within the oven, a flow-through ventilation fume exhaust system, and a timer for controlling the delivery of microwave energy to a sample; providing an acid resistant, non-microwave absorbent sample container; placing a pre-determined weight of sample to be digested within the sample container; adding a volume of acid mixture to the container in proportion to the pre-determined sample weight; placing the prepared sample mixture and container within the sample receiving box; setting the timer and energizing the microwave oven so as to produce a pre-determined degree of digestion of the sample.
Claim 2
Independent Claim
122 words
A method for the chemical digestion, prior to analysis, of organic samples comprising the steps of: providing a modified microwave oven formed with an acid fume resistant sample receiving box disposed within the oven, a flow-through ventilation fume exhaust system, and a timer for controlling the delivery of microwave energy to a sample; providing an acid resistant, non-microwave absorbent sample container; placing a pre-determined weight of sample to be digested within the sample container; adding a volume of acid mixture to the container in proportion to the pre-determined sample weight; placing the prepared sample mixture and container within the sample receiving box; setting the timer and energizing the microwave oven so as to produce a pre-determined degree of digestion of the sample.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein: the acid mixture is added in the proportion of 7 to 10ml. for each 0.5g of sample weight.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein: the acid mixture for sample digestion is a 4:1 mixture of reagent grade nitric and perchloric acids.
Claim 5
Dependent Claim
56 words
Apparatus for the chemical digestion of organic sample materials comprising: a microwave oven generally in the form of a rectangular box and having a source of microwave energy; an acid fume resistant sample receiving box disposed within said microwave oven; and means defining a flow-through ventilation system through said oven and through said sample receiving box.
Claim 6
Dependent Claim
56 words
Apparatus for the chemical digestion of organic sample materials comprising: a microwave oven generally in the form of a rectangular box and having a source of microwave energy; an acid fume resistant sample receiving box disposed within said microwave oven; and means defining a flow-through ventilation system through said oven and through said sample receiving box.
Claim 7
Dependent Claim
39 words
The apparatus of claim 4 including: suction means for creating a negative pressure within said sample receiving box for thereby withdrawing acid fumes generated during the chemical digestion of sample material when heated from said source of microwave energy.
Claim 8
Dependent Claim
29 words
The apparatus of claim 5 including: a fume scrubber means interconnected between said sample box and said suction means for treating the acid fumes exhausted from said sample box.
Claim 9
Dependent Claim
38 words
The apparatus of claim 4 including; timing means interconnected with said source of microwave energy for controlling and limiting the delivery of microwave energy to a sample so as to obviate the boiling over of a sample mixture.
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) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |