Standard Methods: 7500-I C: Radioactive Iodine by Ion-Exchange
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Official Method Name
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7500-I C. Ion-Exchange Method |
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Current Revision
| Standard Methods Online |
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Media
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WATER |
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Instrumentation
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Beta Counter |
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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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A known amount of inactive iodine in the form of KI is added as a carrier and the sample is taken through an oxidation-reduction step using hydroxylamine and sodium bisulfite to convert all iodine to iodide. Iodine, as the iodide, is concentrated by absorption on an anion-exchange column. Following an NaCl wash, iodine is eluted with sodium hypochlorite. Iodine in the iodate form is reduced to I2, extracted into CCl4, and back extracted as iodide into water. The iodine finally is precipitated as PdI2. |
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Scope and Application
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Method 7500-I C, in which iodide is concentrated by absorption on an anion resin, purified, and counted in a beta gamma coincidence system, is sensitive and accurate. |
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Applicable Concentration Range
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Interferences
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Quality Control Requirements
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See Section 7020 Quality Assurance/Quality Control. |
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Sample Handling
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Plastic or glass containers. No preservation. |
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Maximum Holding Time
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14 days |
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Relative Cost
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Greater than $400 |
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Sample Preparation Methods
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