THE LIQUID SCINTILLATION COUNTING OF C$sup 14$$O$$sub 2$ ABSORBED ALKALI- SPOTTED FILTER PAPER
In the Bosquet and Christian method (Anal. Chem., 32: absorbed on filter paper immersed in a phosphor solution is attained. It is proposed that respiratory C/sup 14/O/sub 2/ evolved during the course of incubation may be counted more expediently by transferring the alkali-spotted filter paper directly from the Warburg vessel to a vial containing phosphor solution, and counting the filter paper together with the absorbed C/sup 14/O/sub 2/ on a liquid scintillation counter. Precautions necessary to obtain valid counting rates using this procedure are evaluated. It was shown that toluene was a more satisfactory solvent than dioxane for the phosphor (2,5-diphenyloxazole and 1,4- bis-2(5-phenyloxazolyl)-benzene) solution. The volume of alkali solution applied to the filter paper should not exceed the capacity of the filter paper to retain the alkali in a discrete spot in the center of the filter paper. It was found that a dropper calibrated to deliver drops of 20 mu l is best for this purpose. The quality of the filter paper used (Whatman No. 3 was satisfactory) should not be such that its absorptive capacity is not exceeded by the volume of fluid added. Allowance should be made for the fact that different volumes of phosphor solution in the counting vial affect the counting efficiency. The efficiency with which C/ sup 14/ is counted with this technique varies with the nature of the C/sup 14/- labeled compound on the filter paper, and allowance should be made for this. For example, it was shown that the efficiency with which C/sup 14/O/sub 2/ was counted was only 66% of that with which ciency with C/sup 14/O/sub 2/ is not clear. It was concluded that the counting of respiratory C/sup 14/O/sub 2/, by placing the alkali-spotted filter paper from the center well of a Warburg vessel directly in a phosphor solution in a counting vial and counting with a liquid scintillation counter, provides a rapid and reliable method for determining the radioactivity of respiratory CO/sub 2/ provided the above-mentioned precautions are taken. (BBB)
- Research Organization:
- Univ. of Cape Town, South Africa
- NSA Number:
- NSA-18-012238
- OSTI ID:
- 4114962
- Journal Information:
- S. African J. Lab. Clin. Med., Vol. Vol: 9; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ADSORPTION
ALKALI METALS
AMINO ACIDS
CARBON 14
CARBON DIOXIDE
CONFIGURATION
COUNTERS
DIOXANE
EFFICIENCY
ERRORS
FILTERS
GAS FLOW
GASES
GLYCINE
GRAIN SIZE
HETEROCYCLICS
HYDROXIDES
LABELLED COMPOUNDS
LABORATORY EQUIPMENT
LIQUIDS
LUNGS
OPERATION
PAPER
PHOSPHORS
RADIATION DETECTORS
RADIOCHEMISTRY
SCINTILLATION COUNTERS
SOLUTIONS
SOLVENTS
TOLUENE
USES
VARIATIONS
VESSELS
VOLUME
WATER