Measurement uncertainty of iodine determination in radiochemical neutron activation analysis

The Potential Of I-129 as an Environmental Tracer

“…During irradiation radioactivity in sample is produced mainly due to the radioisotopes 23 Na(n, ) 24 Na (T ½ = 14.96 hours), 41 K(n, ) 42 K (T ½ = 12.36 hours) and 81 Br(n, ) 82 Br (T ½ = 35.30 hours) present in sample, which renders the direct measurement of 130 I after irradiation and radiochemical separation of induced 130 I after irradiation is necessary. Solvent extraction with CCl 4 or CHCl 3 are normally used to extract iodine (Osterc & Stibilj, 2005;Osterc et al, 2007). In first step pre-concentration of iodine from large amounts of sample is performed.…”

“…In first step pre-concentration of iodine from large amounts of sample is performed. Solid samples, such as soil, sediment, vegetation, biological samples can be decomposed by alkaline fusion (Hou et al, 1999, Osterc et al, 2007. The sample is mixed with potassium hydroxide/alkali solution and then gradually heated to 600 °C.…”

“…Iodine is leached from the decomposed sample with hot water, isolated with solvent extraction and precipitated as PdI 2 or MgI 2 or trapped on activated charcoal (Fig. 2) (Hou et al, 1999, Osterc et al, 2007. Another method to separate iodine from solid samples is combustion at high temperature, ~1100 °C .…”

Natural iodine in a clay formation: Implications for iodine fate in geological disposals

“…In order to stabilize the signal and minimize memory effect, samples as well as standard solutions used for calibration contained 0.25% TMAH (tetramethyl ammonium hydroxide) (Muramatsu and Wedepohl, 1998;Tagami and Uchida, 2005) RNAA was performed by the Josez Stefan Institute in Slovenia (Dermelj et al, 1990;Osterc and Stibilj, 2005;Osterc et al, 2007). 180 mg of rock powder was pelletized with 120 mg of cellulose powder.…”

“…The irradiated sample and 90-100 mg of iodine* carrier (solution of KI in NH 3 ; 50mg I g -1 in 5% solution of NH 3 ) were then combusted in an oxygen atmosphere (4 L Schöninger flask) containing a reducing acid solution. Iodine* was extracted with chloroform via the classical redox reaction with NaNO 2 (See Osterc and Stibilj (2005) for the detailed procedure). Stripping of the organic phase to purify iodine* followed, which was then re-extracted with chloroform and transferred to a vial for gamma-ray measurement of the induced radionuclide ( 127 I(n,γ) 128 I, σ th = 6.2 b, t 1/2 = 25…”