An Evaluation of Three Halogens (Cl, Br, and I) Data from a Geological Survey of Japan Geochemical Reference Materials by Radiochemical Neutron Activation Analysis

Abstract

Fifteen Geological Survey of Japan (GSJ) geochemical reference materials were analyzed to determine the contents of three halogens (Cl, Br, and I) by using instrumental neutron activation analysis (INAA) and/or radiochemical NAA (RNAA). Two reference materials (JCp-1 and JSO-1) were analyzed using both INAA and RNAA. Although there were discrepancies in Cl and Br for JCp-1 between the INAA and RNAA data, probably due to sample heterogeneity, the INAA and RNAA data for JSO-1 were consistent with each other, within less than 7%, indicating that our RNAA data are reliable. With the repeated analyses of JR-3, the external repeatability of the data obtained using RNAA was evaluated to be 18% for Cl, 11% for Br, and 19% for I. Our RNAA data are in agreement with literature values using NAA for the three halogens, as well as those using isotope dilution mass spectrometry and ion chromatography for Cl. Systematically lower values when using neutron irradiation noble gas mass spectrometry (NI-NGMS) and inductively coupled plasma mass spectrometry (ICP-MS) with pyrohydrolysis can be observed, implying that there are losses for noble gas nuclides produced through the beta-decay of the neutron capture halogen nuclides in NI-NGMS and the non-quantitative recovery of Br and I during procedures in ICP-MS, respectively.