Combustion method apparatus for preparing samples for liquid scintillation counting

Claim 3

A process for the combustion of organic material containing a radioactive isotope in an oxygen atmosphere to produce gaseous by-products for subsequent radio-activity determinations comprising placing a sample of organic material between two ignition electrodes, blanketing the sample with oxygen, generating an electric spark between the electrodes from an oscillating electric current having a frequency of from 20 cps to 25,000 cps and of sufficient energy to excite oxygen to convert a portion of the oxygen to reactive singlet and triplet oxygen, directing said spark to the surface of the sample to generate additional quantities of singlet and triplet oxygen and to provide locally sufficient heat to effect oxidation and combustion at the surface of the sample, continuing localized combustion, and burning away portions of the sample thereby, until the sample is completely converted to its gaseous combustion products, and collecting said gaseous combustion products.

Claim 4

A process for the combustion of organic material containing a radioactive isotope in an oxygen atmosphere to produce gaseous by-products for subsequent radio-activity determinations comprising placing a sample of organic material between two ignition electrodes, blanketing the sample with oxygen, generating an electric spark between the electrodes from an oscillating electric current having a frequency of from 20 cps to 25,000 cps and of sufficient energy to excite oxygen to convert a portion of the oxygen to reactive singlet and triplet oxygen, directing said spark to the surface of the sample to generate additional quantities of singlet and triplet oxygen and to provide locally sufficient heat to effect oxidation and combustion at the surface of the sample, continuing localized combustion, and burning away portions of the sample thereby, until the sample is completely converted to its gaseous combustion products, and collecting said gaseous combustion products.

Claim 5

The process of claim 2 wherein the oxygen is preheated prior to introduction into the combustion chamber for the purpose of enhancing the formation of excited oxygen states and to dry the sample of excess water vapor.

Claim 6

The process of claim 2 wherein nitrogen gas is preheated and introduced into the combustion chamber prior to the oxygen for the purpose of volatilizing and driving off highly combustible sample ingredients which could form an explosive mixture in the presence of oxygen.

Claim 7

The process of claim 2 further comprising passing the gaseous combustion products to collection traps containing collection solvents for subsequent use in liquid scintillation counting, and wherein the combustion chamber and collection traps are purged with nitrogen gas after the combustion step to remove any residual combustion products from their walls.

Claim 8

In a method of oxidizing organic samples containing radioactive isotopes using oxygen supplied to an air-tight combustion chamber to produce gaseous oxides for subsequent radioactivity determinations, the improvement comprising positioning an organic sample between two spaced electrodes in said combustion chamber, and energizing said electrodes with an oscillating electrical potential to produce and sustain an electrical spark passing between the electrodes and through the aforesaid sample to ionize oxygen in said chamber and to produce localized heating in said sample, thereby effecting total oxidation of said sample into gaseous oxides, and collecting said gaseous oxides.

Claim 9

In a method of oxidizing organic samples containing radioactive isotopes using oxygen supplied to an air-tight combustion chamber to produce gaseous oxides for subsequent radioactivity determinations, the improvement comprising positioning an organic sample between two spaced electrodes in said combustion chamber, and energizing said electrodes with an oscillating electrical potential to produce and sustain an electrical spark passing between the electrodes and through the aforesaid sample to ionize oxygen in said chamber and to produce localized heating in said sample, thereby effecting total oxidation of said sample into gaseous oxides, and collecting said gaseous oxides.