以超臨界流體層析來討論多環方香烴化合物在不同吸附劑下吸附及脫附的行為

Abstract

近年來利用吸附劑採集環境污染物,並且配合超臨界二氧化碳以萃取分析 的研究日趨增加, 使得分析物在不同吸附劑上的吸附及脫附行為的探討越 形重要.本研究首先在自製的管柱中填充吸附劑,再配合超臨界流體層析來 討論PAHs在吸附劑上吸附及脫附現象.由Van't Hoff plot中得到PAHs在吸 附劑與超臨界二氧化碳之間的轉移能,來解釋由於吸附劑性質的影響將使 得PAHs在吸附劑上吸附及脫附行為產生差異.將此結果配合超臨界流體萃 取的數據,就可以建立起此二者之間的關聯性,於是若要了解特定溶質在不 同吸附劑上吸附及脫附的現象時,便可由此溶質在吸附劑上滯留的情形得 知,所以當針對採集分析物之特性和如何選用回收率較高的吸附劑,將對於 萃取過程中最佳條件的選則有較準確且迅速的幫助. In recent years,solid phase extraction technique has intensively utilized in trapping environmental pollutants, followed by solvent or supercritical fluid elution for sample preconcentraction.Subsequently the adsorption and desorption behavior of analytes on various adsorbents under supercritical fluid chromatography to study polycyclic aromatic hydrocarbons with column packed with desired adsorbent. Thermodynamic enthalpies obta from the Van't Hoff plots represent the phase transfer energy between adsorbent and supercritical fluid carbon dioxide. The results demonstrate the strongest adsorption of PAHs on XAD-4 among the four adsorbents studied. The chromatographic peaks of PAHs show serious tailing. The transfer energy delines follwed by XAD-2, Tenax-TA, and C18. The analyte peaks are gaussian-like on the column packed with C18. The interaction strength of PAHs on adsorbents various due to their physical properties that are dissussed in some detail. This outcome evebtually could be correlated to the extraction recovery with the aid of analyte using SFE after solid phase extraction would be forecast by this simple technique untead of exercising iterative SFE.