Standard Methods: 7500-I B: Radioactive Iodine by Precipitation

Summary
Analytes
Revisions
Data and Sites

Official Method Name

7500-I B. Precipitation Method

Current Revision

Standard Methods Online

Media

WATER

Instrumentation

Beta Counter

Method Subcategory

Radiochemical

Method Source

Standard Methods

Citation

Standard Methods Online - Standard Methods for the Examination of Water and Wastewater

Brief Method Summary

Iodate carrier is added to an acidified sample and, after reduction with Na₂SO₃ to iodide, the ¹³¹I is precipitated with AgNO₃. The precipitate is dissolved and purified with zinc powder and H₂SO₄ and the solution is reprecipitated as PdI₂ for counting.

Scope and Application

The precipitation method (7500-I B) is preferred because it is simple and involves the least time.

Applicable Concentration Range

Interferences

Quality Control Requirements

See Section 7020 Quality Assurance/Quality Control.

Sample Handling

Plastic or glass containers. No preservation.

Maximum Holding Time

14 days

Relative Cost

Greater than $400

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Iodine-131(10043-66-0) Iodine-131	1.000 pCi/L	N/A	N/A

Precision Descriptor Notes:
Detection Level Note:	1 pCi I-131/L

Revision	PDF/Link
Standard Methods Online
Standard Methods 18th, 19th, 20th ed.

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Standard Methods: 7500-I B: Radioactive Iodine by Precipitation

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