DOE EML: 3H-04-RC: Tritium in Water - Liquid Scintillation Counting
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Official Method Name
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Tritium in Water - Liquid Scintillation Counting |
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Current Revision
| EML Procedures Manual HASL-300, Volume 1, 28th Ed.(1997) |
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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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The 3H spectral range or window setting is first defined. The counting efficiencies are then determined by using efficiency curves (quench curves). The efficiency curve is a plot of the counting efficiency as a function of the quench index parameter (QIP). The QIP is also known as the automatic external standardization (AES) number or the transformed spectral index of the external standard (tSIE). A sample aliquot is prepared with a measured volume of a scintillation cocktail that is then placed in a programmed LS counter for spectrum analysis. |
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Scope and Application
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The procedure is used for the rapid determination of tritium by liquid scintillation (LS) spectrometry. It applies to all clear liquid samples and it can be completed in a short period (1 to 2 h) once efficiency curves have been established. The procedure is designed for a Tri-Carb 2250CA LS counter using Insta-Gel XF cocktail and it requires distillation of the samples so that they are free of salts and other interfering radionuclides. |
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Applicable Concentration Range
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None given. |
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Interferences
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(A) 3H Distillation: Perform a 3H distillation if information more accurate than gross tritium is needed. (B) High Count Rates: Reanalyze samples with excessively high count rates (e.g., > 1,000,000 counts min-1) using less sample material. (Note: When using this procedure, the calculated 3H concentration may be higher than the actual concentration because of possible interferences from other low-energy beta emitters and the beta continuum of high energy beta particles.) (C) Efficiency Drops - Add several drops of 30% H2O2 to the vial to bleach the sample if quenching causes the efficiency to drop to one fourth of the highest efficiency. (Note: Deep color in the samples may cause severe quenching that will lower the counting efficiency.) (D) Cross contamination: High-level and low-level samples should be processed in independent batches to minimize possibility of cross contamination. |
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Quality Control Requirements
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QC samples should be analyzed to ensure required limits of precision and accuracy are being met. QC samples include instrument calibration standards, blank samples, control samples, an "spiked" samples. |
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Sample Handling
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None given. |
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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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