インライン還元-蛍光検出HPLCを用いる多環芳香族炭化水素キノン分析法の改良と大気粒子抽出物への適用

摘要

多環芳香族炭化水素(polycyclic aromatic hydrocarbon; PAH)の酸化体であるPAHキノン(PAHQ)類は，ディーゼル排気中や大気中粒子状物質から検出されており，私たちは呼吸によりこれらを生体内に取り込んでいる危険性が高い. PAHQは生体内での活性酸素種生成能を有し，細胞内で酸化ストレスを誘導することが知られているほか，呼吸器•循環器系疾患ゃアレルギー性疾患に対して増悪作用を示すことが報告されている. PAHQの中には粒子径2μm以下の微粒子中に存在するものも確認されており，これらは肺胞への到達率が高ことから人体への健康影響が一層懸念される.しかし，実大気粒子抽出物中のPAHQを分析した例はPAHの分析例に比べて極めて少ない.その理由のーつとして，簡便かつ高感度なPAHQの測定法が確立されていなかったことが挙げられる.%A simple and sensitive method for measuring quinoid polycyclic aromatic hydrocarbons (PAHQs) in soluble organic fraction (SOF) of airborne particles based on two-dimensional high-performance liquid chromatography (HPLC) with fluorescence detection was established. The system involves a reversed phase column with naphtylethyl groups bonded silica packing material for sample clean-up, a 6-port switching valve, an ODS column for trapping the fraction containing PAHQs, a reversed phase column with cholesteryl groups bonded silica packing material for sample separation, and a Pt-Rh catalytic column for the reduction of PAHQs to a corresponding fluorescent compound. The accuracy of the assay, as applied to airborne particulate sample extracts spiked with known amounts of PAHQs were 91-107%. The detection limits were 19 to 2000 fmol per injection (signal-to-noise ratio = 3), and the calibration range was from 1 to 100 pmol with excellent proportionality (R~2 ≥ 0.9992) for four kinds of PAHQs: benz[α]anthracene-7,12-dione, fluoranthene-2,3-dione, pyrene-1,6-dione, and pyrene-1 ，8-dione. PAHQs in SOF of airborne particles collected in Kyoto, Japan were successfully measured using the established analytical method with simple sample-preparation steps: ultrasonic extraction in organic solvent and concentration under reduced pressure and/ or a nitrogen stream.