高純度試薬中の微量不純物分析

摘要

超純水、高純度酸の分析において、蒸発乾固を利用した主成分の除去、ならびに目的元素の濃縮を行った。その結果、Al、Ca、Cd、Co、Cr、Cu、Fe、K、Li、Mg、Mn、Na、Ni、Pb及びZnの15元素についてpgmL￣1レベルの超微量不純物分析が可能となった。高純度水酸化ナトリウム水溶液の分析において、キレート樹脂または陰イオン交換樹脂を利用してNa主成分を分離することにより、測定液中のNa濃度をFLgg~(-1)レベルに低減することができた。その結果、創、Cd、Co、Cr、Cu、Fe、Mn、Ni、Pb及びZnの10元素についてng g~(-1)レベルの微量不純物分析が可能となった。Crについてはキレート樹脂によりCr（Ⅲ）、陰イオン交換樹脂によりCr（Ⅵ）を分別定量することが可能となった。%The determination of trace impurities in a highly purified reagent. Ultra pure water, hydrochloric acid and hydrofluoric acid : the sample was evaporated to dryness on a heater. The residue was dissolved by nitric acid. The trace elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb and Zn) of pg Ml~(-1) level were determined by inductively coupled plasma mass spectrometry (ICP-MS). The recovery of each element was greater than about 80%. Aqueous sodium hydroxide : the removal of major element (Na) could be carried out by chelating resin which has an iminodiacetic acid group. After conditioning, the chelating resin was run through with sample and an ammonium acetate buffer and water to remove the major element, such as Na, and was then eluted with 3M nitric acid. Cr(VI) was determined by the anion-exchange method. Cr(VI) was adsorbed on an anion-exchange resin disk. The anion-exchange resin was washed with ultra pure water to remove the major element, and was then eluted with 20% nitric acid. The trace elements (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) of ng g~(-1) level were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) or ICP-MS. The recovery of each element was greater than about 80%, and Na concentration was decreased to μ g g~(-1) level in the final solution.