title: Accurate and precise measurement of selenium by instrumental neutron activation analysis.
abstract: An accurate and precise measurement of selenium in Standard Reference Material (SRM) 3149, a primary calibration standard for the quantitative determination of selenium, has been accomplished by instrumental neutron activation analysis (INAA) in order to resolve a question arising during the certification process of the standard. Each limiting factor of the uncertainty in the activation analysis, including the sample preparation, irradiation, and γ-ray spectrometry steps, has been carefully monitored to minimize the uncertainty in the determined mass fraction. Neutron and γ-ray self-shielding within the elemental selenium INAA standards contributed most significantly to the uncertainty of the measurement. An empirical model compensating for neutron self-shielding and reducing the self-shielding uncertainty was successfully applied to these selenium standards. The mass fraction of selenium in the new lot of SRM 3149 was determined with a relative standard uncertainty of 0.6%.
authors.affiliation: Korea Research Institute of Standards and Science, Daejeon, Republic of Korea.
authors.forename: In Jung
authors.initials: IJ
authors.lastname: Kim
authors.forename: Russell P
authors.initials: RP
authors.lastname: Watson
authors.forename: Richard M
authors.initials: RM
authors.lastname: Lindstrom
mesh_terms: D002138:Calibration; D016014:Linear Models; D009502:Neutrons; D011854:Radiochemistry / Q000295:instrumentation* / Q000592:standards; D012015:Reference Standards; D012643:Selenium / Q000032:analysis*; D035501:Uncertainty
chemical_list: D012643:Selenium