Windal I, Miller DJ, Hawthorne SB
Mass Spectrometry Laboratory, University of Liege, Belgium.
Anal Chem. 2000 Aug 15;72(16):3916-21. doi: 10.1021/ac9914972.
This study investigates the replacement of Soxhlet extraction by supercritical fluid extraction (SFE) or accelerated solvent extraction (ASE) for the removal of dioxins from municipal waste incinerator fly ash. SFE is very matrix dependent; higher percent recoveries versus Soxhlet extraction can be obtained for low-carbon-level fly ash, but only a few percent of dioxins can be extracted from high-carbon-level fly ash. The addition of large quantities of toluene in the extraction cell prior to extraction of high-carbon fly ash improves the recovery of the lowest chlorinated dioxins (approximately 90%), but a maximum of 20% of the octachlorodibenzo-p-dioxins can be extracted. Since large quantities of toluene are needed to improve the recoveries, ASE with toluene was tested. Recoveries similar to Soxhlet extraction can be obtained in 2 h at 80 degrees C. Increasing the temperature to 150 degrees C increases the extraction rate and yields recoveries of approximately 110-160% compared to 48-h Soxhlet extraction for all congeners for both low- and high-carbon fly ashes. These results question the choice of Soxhlet extraction as a reference method for dioxin determination.
本研究探讨了用超临界流体萃取（SFE）或加速溶剂萃取（ASE）替代索氏提取法，以去除城市垃圾焚烧炉飞灰中的二恶英。超临界流体萃取非常依赖基质；对于低碳含量的飞灰，相对于索氏提取法可获得更高的回收率，但对于高碳含量的飞灰，只能提取出百分之几的二恶英。在萃取高碳飞灰之前，在萃取池中加入大量甲苯可提高最低氯代二恶英的回收率（约90%），但八氯二苯并对二恶英的最大萃取率为20%。由于需要大量甲苯来提高回收率，因此测试了用甲苯进行加速溶剂萃取。在80℃下2小时可获得与索氏提取法相似的回收率。将温度提高到150℃可提高萃取速率，与48小时的索氏提取法相比，低碳和高碳飞灰中所有同系物的回收率约为110 - 160%。这些结果对选择索氏提取法作为二恶英测定的参考方法提出了质疑。
