Determination of bromine and iodine in biological and environmental materials using epithermal neutron activation analysis

Epithermal neutron activation analysis (ENAA) was applied to the determination of the contents of bromine and iodine in 40 biological and environmental standard reference materials and Chinese diets. Boron nitride (BN) for solid samples and BN+Cd for liquid samples were adopted as shield material. Irradiation was carried out in inner and outer irradiation sites in a Miniature Source Reactor (MNSR) for solid and liquid samples, respectively. The 443 keV photopeak of I-128 and the 616 keV photopeak of Br-80 were used, The precision of measurement (relative standard deviation) is 2 similar to 6% for contents of iodine of more than 100 ng/g and 8 similar to 12% in the 20 similar to 100 ng/g range in solid samples, and 12 similar to 18% at less than 100 ng/ml in liquid samples. For bromine. the precision of measurement is 2-8% for solid samples and lower than 13% for liquid samples. The detection limits under experimental conditions varied between 10 similar to 30 ng/g, 55 similar to 95 ng/g and 25 similar to 68 ng/g for iodine and 50 similar to 150 ng/g, 200 similar to 450 ng/g and 100 similar to 300 ng/g for bromine in ENAA with BN shield in inner irradiation sites, with Cd Shield and BN+Cd shield in outer irradiation sites, respectively.