Preconcentration of Trace Chalcophile Elements by a Zincon-loaded Resin and Its Application to Neutron Activation Analysis

Abstract

A chelating agent-loaded resin consisting of an anion exchange resin and zincon whic has widely been employed as a specific reagent for zinc (II) and copper (II) in spectrophotometry was prepared. The adsorption behavior of some chalcophile elements was studied in detail, with respect to pH, flow rate and exchange capacity. From the results, it was confirmed that the zincon-loaded resin reacts selectively with copper (II), zinc (II), mercury (II) and lead (II) at lower pH region, and the above reaction is stoichiometric as in the case of the reaction of zincon with metal ions in aqueous solution. Furthermore, the zincon-loaded resin was applied to the selective concentration of trace amounts of chalcophile elements in natural water samples prior to neutron activation analysis. Water samples taken from the Watarase River were filtered and the pH of each filtrate was adjusted to ca. 5.5. After preconcentration was made by the column method (zincon-loaded resin: 2×10^-4 mol/g resin, 1.0 g, 7 mmφ×35 mm), the resin in the column was washed and dried in a desiccator. The standard material was also prepared according to the above mentioned scheme. The sample and the standard materials packed in polyethylene vials were irradiated for 40 min by a neutron flux of 5×10¹³ n⋅cm^-2⋅sec^-1 in the JRR-4 of the Japan Atomic Energy Research Institute. After cooling the materials, activity measurements were made. The results were 53 ppb for copper, 0.25 ppb for mercury.