A Method for Determining Iodine-129 in Milk and Water

Abstract

An analytical method for dete~mining'~~1 in environmental milk and water samples is described. The method depends on the specificity of elemental iodine separation by solvent extraction, followed by liquid scintillation counting of the low-energy beta emissions from lz91. Iodine, as iodide, is concentrated by sorption on an anion exchange column and eluted with NaOCI. After reduction to I,, the iodine is extracted into CCI,, back extracted into water, cleaned by one toluene-water extraction cycle, and finally extracted into toluene. Chemical recovery of the added carrier is determined spectrophotornetrically on a small aliquot of the toluene extract. The 12g1 concentration is determined by liquid scintillation counting of the toluene solution.Average per cent recovery of iodine carrier is 74 f 2 for water, 58 =k 3 for raw milk and 80 4 for pasteurized milk. Analytical sensitivity is 0.3 pCi lZ0I/1. for a 4-1. sample.

Determination of 129I in seawater and some environmental materials by neutron activation analysis

“…27 For extracting all iodine with CCl 4 as I 2 , all chemical species of iodine were usually oxidized to IO 4 2 with NaClO at pH 10, after which the IO 4 2 was reduced to I 2 by NH 2 OH•HCl at 2-3 mol l 21 of HNO 3 . 8,28 It will consume a large quantity of HNO 3 . Sulfurous acid or its salt is a strong reductant, and was usually used to reduce I 2 to I 2 in the determination of iodine.…”

The Determination of 125I and 129I Using an Intrinsic-germanium Detector for X-ray Spectroscopy

“…The procedures are basically the same as those used in the liquid scintillation method of GABAY et al (1974) with two exceptions: The iodine is precipitated as PdI, in the final step, rather than being extracted into toluene, and the chemical recovery is determined gravimetrically rather than spectrophotometrically.…”

Measurement of trace 129I concentrations in CsI powder and organic liquid scintillator with accelerator mass spectrometry

“…The techniques of measuring ı129 with AMS are by now matured, following early works in the 80's [10]. They improve over the various other measurement methods with Radiochemical Neutron Activation Analysis [11], Inductively Coupled Plasma Mass Spectrometry [12] and Liquid Scintillation Counting [13]. The AMS technique has strong rejection capabilities for isobaric, molecular and isotopic interferences, providing powerful background suppression.…”