Preconcentration using thermo-responsive polymers for the fluorometry of polycyclic aromatic hydrocarbons in air and water

提出了一种不使用有机溶剂，利用热响应聚合物（TRP）预富集分离空气中痕量多环芳烃（PAHs）的方法。聚乙烯基甲基醚（PVME）和聚n -异丙基丙烯酰胺（PNIPAAm）作为TRP，在低于31ºC的水中可溶，但在高于31ºC时加热突然凝固，变得不溶。将空气样品泡入低于31℃的0.035% PVME水溶液中，溶解空气中的多环芳烃。将PVME与溶液在53℃下进行相分离，得到的固体PVME中捕获了多环芳烃，并粘附在反应容器壁上。用滗析法丢弃上清溶液后，将多环芳烃与PVME一起溶解在极小体积的乙腈中。各多环芳烃采用荧光检测反相柱高效液相色谱分离定量。该方法对芴、蒽、菲、氟蒽、芘、苯并[a]蒽、苯并[a]芘等11种多环芳烃进行了分析。检出限为0.6 pmol/次。色氨酸捕获多环芳烃的机理至今尚未明确。然而，从含有PVME和苯的溶液的核磁共振提供的信息来看，PAHs的捕获可能是通过氢键和非极性键将PAHs结合到PVME中。

A preconcentration and separation procedure using thermo-responsive polymer (TRP) was proposed for determining trace amounts of polycyclic aromatic hydrocarbons (PAHs) in air without using organic solvent. Poly (vinylmethylether) (PVME) and poly (N-isopropylacrylamide) (PNIPAAm) were examined as TRP which is soluble in water below 31ﾟC but solidified abruptly on heating above 31ﾟC becoming insoluble. Air sample was bubbled into 0.035% PVME aqueous solution below 31ﾟC to dissolve the PAHs in air. With phase separation of PVME from the aqueous solution at 53ﾟC,PAHs were captured in the resulting solid PVME which stuck to the wall of the reaction vessel. After discarding the supernatant solution by decantation, the PAHs were dissolved in a very small volume of acetonitrile together with PVME.Each PAH was separated and quantified by HPLC with reversed phase column using fluorescence detection. The method was applied to 11 kinds of PAHs such as fluorene, anthracene, phenanthrene, fluoranthene, pyrene, benzo[a]anthracene, and benzo[a]pyrene. The detection limit was 0.6 pmol/test.The mechanism for capturing of PAHs by TRP has so far not been clarified. However, it seems likely by information provided by NMR of solution containing PVME and benzene that capture of PAHs takes place by association of PAHs into PVME by hydrogen bonding and nonpolar bonds.