DOE RESL: CHEM-TP-FE.1: Fe-55 in Water by Liquid Scintillation Counting
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Official Method Name
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Fe-55 in Water |
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Current Revision
| April 1999 |
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Media
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WATER |
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Instrumentation
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Liquid Scintillation Counting |
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Method Subcategory
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Radiochemical |
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Method Source
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Citation
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Brief Method Summary
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Iron (Fe) is first precipitated as the hydroxide is dissolved in 10 M HCl. The solution is passed through an anion exchange column that has been equilibrated with 12 M HCl. The Fe-55 is selectively eluted with 0.1 M HCl after eluting and discarding interfering nuclides with 6 M and 4 M HCl. Concentrated H3PO4 is added to the eluant containing the Fe and the solution boiled down to a colorless solution of H3PO4. Water and scintillator are added and the mixture is shaken prior to counting. |
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Scope and Application
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This procedure is applicable to the liquid-scintillation measurement of Fe-55 after its chemical separation from environmental waters and various liquids collected at nuclear reactor facilities. |
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Applicable Concentration Range
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None given. |
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Interferences
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(A) Higher Fe-59 energies: Many samples contain Fe-59, thus a correction for the overlap of much higher energy Fe-59 beta spectrum into the low energy Fe-55 spectral region is necessary. (B) Sample volumes: The volume of sample used depends on activity level as well as on the amount of stable iron present. Low activity samples can be concentrated by evaporation, and high activity samples can be analyzed by taking small aliquots. The iron in eluent taken plus the 10 mg of iron carrier added should not exceed 20 mg. |
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Quality Control Requirements
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A reagent blank must be included with each set of samples analyzed. A Fe-55 std must also be prepared and counted to determine of the counting efficiency of each set of samples. An occasional Fe-59 control sample should be carried through the procedure to check chemical yield and spectral overlap. Correct performance of the liquid scintillation counter must be verified by an Instrument Performance Analysis (IPA) at the end of counting each sample set. |
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Sample Handling
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Low activity samples can be concentrated by evaporation, and high activity samples can be analyzed by taking small aliquots. |
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Maximum Holding Time
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None given. |
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Relative Cost
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$51 to $200 |
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Sample Preparation Methods
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