天然水中微量金属の多元素濃縮用キレート樹脂充填ミニカラムの開発

摘要

Trace metals in natural water are sensitive indicators of geochemical processes and reactions, environmental pollutions, and bioactivities, though these elements are present in extremely low concentrations. Determination of trace metals in natural water is still a challenge for analysts, even using the most advanced available analytical instrument such as ICP-MS. In order to overcome this difficulty, a chelating resin-packed minicolumn was developed to preconcentrate trace metals in natural water. The minicolumn was constructed by packing a slurry of Chelex 100 resin into the space of the outlet of a syringe filter (DISMIC-25HP, ADVANTEC), which was then capped with another syringe filter (Millex-LH, Nihon Millipore Kogyo). Furthermore, a procedure for the preconcentration of trace metals in natural water using the present minicolumn was established by carefully optimizing each operating parameter. As a result, a concentration factor of 20-fold was achieved for trace metals using only 50 mL of a natural water sample, where the recovery values for most of the trace metals were more than 80% with a standard deviation less than 5%. The effectiveness of the present analytical method was assessed by determining trace metals in seawater certified reference materials (NASS-5, CASS-3, and CASS-4). Furthermore, determination of trace metals in seawater, river water, and mineral water samples was carried out to assess the environmental pollution of trace metals in natural water and the mineral nutriment in mineral water, respectively.%地下水や河川水，湖水，海水などの天然水に含まれる微 量金属の濃度は，環境汚染やpHなど化学条件の変化，生 物活動による影響を強く受けて変動し，多様な濃度分布を 示す．このことは，天然水中の微量金属の濃度分布を測定 すれば，水質環境や元素の循環に関する有益な情報が得ら れることを意味しており，天然水中微量金属の定量は従来 より継続して取り込まれてきた．現在，天然水中の微量金 属元素の分析法として最も応用が盛んなのが誘導結合プラ ズマ質量分析法（ICP-MS）である．