A rapid method for estimating iodine-125 in water samples using X-ray fluorescence for yield correction

Large sample volumes are needed when monitoring low levels of¹²⁵I in fresh water systems. Small anion exchange resin columns concentrate the radioactivity and also act as counting sources in thin NaI(T1) well scintillation detectors. Isotope identity is confirmed by decay counting or Ge spectroscopy. Recovery corrections are made by comparing the X-ray fluorescence of stable iodide carrier added initially with that retained on the counting column. The benefits from this simple, quick and accurate procedure could be adapted to other radiochemical estimations which rely on carrier recovery.