- 30 januari 2013
Uranium isotopics in a simulated biological matrix
NUSIMEP-4 Uranium isotopic abundances in simulated urine
Taking into account the growing need to detect and trace non-declared nuclear activities, laboratories were invited to demonstrate their capabilities to carry out precise measurements of uranium isotopic ratios and abundances, including the minor isotopes, in a matrix similar to urine.
Urine has become an important matrix for measurements of uranium isotopic ratios, especially for showing the presence of, and therefore exposure to, enriched or depleted uranium and in particular to measure the exposure to depleted uranium in war zones. A large part of the normal daily uptake of uranium in food, drink and by inhalation is filtered by the kidneys and excreted in the urine. Contamination of the environment either by enriched or depleted uranium can be reflected in changed isotopic ratios of the uranium measured in the urine.
In this campaign the participating laboratories were supplied with two samples each containing uranium with certified isotopic abundances (close to natural) in 20 mL of synthetic urine solution. The approximate uranium concentration in each sample was 5 ng·g-1 of urine (ppb).
A participation fee of 100 EUR per laboratory was requested for handling the costs of the campaign. New Member States, Candidate Countries and Western Balkan Countries were exempt from the participation fee. Participants were asked to measure and report the ratios of n(234U)/n( 238U), n(235U)/n(238U) and n(236U)/n(238 U) but submission of the values of any of these ratios were also accepted. The participating laboratories were also asked to complete a questionnaire mainly concerning their experience, the technique used and application of the uncertainty estimations.