Gamma spectroscopic determination of cesium-137 in milk, using simultaneous equations: collaborative study
Baratta, E.J.; Knowles, F.E.
Journal - Association of Official Analytical Chemists 56(1): 204-207
1973
ISSN/ISBN: 0004-5756 PMID: 4801602 Document Number: 62381
A gamma spectroscopic method, using a sodium iodide (thallium-activated) crystal, was evaluated by 25 collaborators for the determination of 137Cs in milk. Overall average recoveries of 295 plus or minus 18.1 and 53 plus or minus 5.3 pCi/1. were obtained for samples containing 305 and 52 pCi/1., respectively. These samples also contained 131I and 140Ba, which did not interfere with the analyses. The slight bias on the low side and the greater dispersion of results for the low level sample were not considered serious. The method has been adopted as official first action.