NEMI Method Summary

Method Summary Information

Method Number: D4785 Media: WATER
Revision: Current edition approved July 10, 2000. Originally published as D4785-88.
Method Source: ASTM International
Subcategory: RADIOCHEMICAL Analytes in this method
Official Name: Standard Test Method for Low-Level Iodine-131 in Water
Descriptive Name Low-Level Iodine-131 in Water
Source Info: ASTM International
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Citation: ASTM Volume 11.02
 
Brief Method
Summary:
 Sodium iodide is added as a carrier prior to performing any chemical separations. The samples undergo an oxidation-reduction process to ensure exchange between the carrier and the radioactive iodide. Hydroxylamine hydrochloride and sodium bisulfite are added to convert all the iodine to iodide which is then removed by anion exchange. Subsequent elution of the iodide followed by oxidation-reduction yields elemental iodine. The elemental iodine is purified by solvent extraction, reduced to iodide, and precipitated as cuprous iodide. The chemical yield is determined from the recovery of the iodide carrier.
Scope And
Application:
 This test method covers the quantification of low levels of iodine-131 in water by means of chemical separation and counting with a high-resolution gamma ray detector. Iodine is chemically separated from a 4-L water sample using ion exchange and solvent extraction and is then precipitated as cuprous iodide for counting.
Applicable
Conc Range:
 > 0.037 Bq/L
Interferences: Stable iodine in the sample will interfere with the chemical yield determination. One milligram of iodine would produce a bias of about -4 %.
QC Requirements: Prior to using this test method, a quality control (QC) program for the instrumentation (high-resolution gamma-ray spectrometer) shall be established when the system is calibrated. Quality control or tolerance charts shall be established. Control limits shall be established with corrective actions when control limits are exceeded.
The project manager, as part of the external quality control program, shall submit blind quality control samples to the analysts along with routine samples. The quality control samples that are routinely used include blank samples, replicate samples, reference material, and spiked samples.
Sample Handling: Collect a sample in accordance with Practice D 3370.
Max Holding Time:
 
Relative Cost: Unknown
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