スチレンジビニルベンゼン共重合体樹脂を用いるローポリウムエアサンプラ一による大気中ガス状多環芳香族炭化水素採取法と迅速前処理法の開発

摘要

森林内における大気中ガス?粒子相多環芳香族炭化水素（PAHs）の同時観測に適した試料採取法及びその迅速前処理法の開発を行った．捕集装置は，粒子捕集用サンプラー，新規開発したガス状PAHs捕集用カートリッジ〔内径35mm，スチレンジビニルベンゼン共重合体樹脂（以下XAD-2）5.0g〕及びローボ1）ウムポンプからなり，吸引流量は20L／minとした．XAD-2からのPAHsの抽出は，ジクロロメタンによる超音波抽出とし，その後，除粒，濃縮及び分析を行った．対象とする8種のPAHsの前処理操作に対する回収率は80～100％であり，また，20分間2回の超音波抽出により95％以上の抽出効率を得ることができた．更に，開発したカートリッジによる大気中ガス状PAHsの捕集効率は，夏季?冬季ともに95％以上であった．本法を用いたFM多摩丘陵（東京都八王子市）内高さ約12mのタワー上部，下部での観測結果から，森林による大気中PAHsの捕捉効果は，粒子相PAHsよりもガス相PAHsのほうが大きい可能性が示唆された．%Simple differential determinations of arsenic (III) and arsenic (V) in environmental water have been developed based on the selective coprecipitation of arsenic(V) with barium sulfate, followed by a tristimulus colorimetric method. Arsenic (V) coprecipitation with barium sulfate occurred in solution, having an excess of barium ion over sulfate ion when barium sulfate was formed. The pH of solution is also a very important factor for arsenic (V) copreciotation. Arsenic (V) was quantitatively coprecipitated with barium sulfate in solutions at pH 3~9, but arsenic (III) was not coprecipitated even at pH 3~9. To 20 mL of the sample solution, which was put into a syringe, a sodium sulfate solution and a barium chloride solution were added successively to cause the coprecipitation of arsenic (V) with barium sulfate. After filtration, arsenic (III) in the filtrate was determined with tristimulus colorimetry. Another portion of the sample solution was used for the determination of total-arsenic [As(III) +As(V)]. The arsenic (V) concentration was obtained by calculating the difference between the total-arsenic and arsenic (III) concentrations. The established method was successfully applied to environmental water samples, such as brackish lake water samples to clarify the behavior of arsenic (III) and arsenic (V) in redox-sensitive water regions.