Determination of Specific Activity of ¹³¹I Solutions via an Iodide Electrode

The specific activity of ¹³¹I solutions is calculated from the measured ¹³¹I activity and the total iodide content. The latter is measured rapidly (within five minutes) and accurately (relative standard deviation of ±1%) with a radiation-insensitive iodide-sensitive membrane electrode that permits accurate iodide measurements of commercially available “carrier-free” high-activity ¹³¹I solutions.