Facultad de Química, Departamento de Química Analítica, Universidad Nacional Autónoma de México, 04510 México D.F., Mexico.
Anal Chim Acta. 2013 Dec 17;805:60-9. doi: 10.1016/j.aca.2013.10.052. Epub 2013 Nov 7.
Dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) is one of the most interesting sample preparation techniques developed in recent years. Although several applications have been reported, the potentiality and limitations of this simple and rapid extraction technique have not been made sufficiently explicit. In this work, the extraction efficiency of DLLME-SFO for pollutants from different chemical families was determined. Studied compounds include: 10 polycyclic aromatic hydrocarbons, 5 pesticides (chlorophenoxy herbicides and DDT), 8 phenols and 6 sulfonamides, thus, covering a large range of polarity and hydrophobicity (LogKow 0-7, overall). After optimization of extraction conditions using 1-dodecanol as extractant, the procedure was applied for extraction of each family from 10-mL spiked water samples, only adjusting sample pH as required. Absolute recoveries for pollutants with LogKow 3-7 were >70% and recovery values within this group (18 compounds) were independent of structure or hydrophobicity; the precision of recovery was very acceptable (RSD<12%) and linear behavior was observed in the studied concentration range (r(2)>0.995). Extraction recoveries for pollutants with LogKow 1.46-2.8 were in the range 13-62%, directly depending on individual LogKow values; however, good linearity (r(2)>0.993) and precision (RSD<6.5%) were also demonstrated for these polar solutes, despite recovery level. DLLME-SFO with 1-dodecanol completely failed for extraction of compounds with LogKow≤1 (sulfa drugs), other more polar extraction solvents (ionic liquids) should be explored for highly hydrophilic pollutants.
分散液液微萃取与漂浮有机液滴的固化（DLLME-SFO）是近年来发展起来的最有趣的样品制备技术之一。尽管已经报道了几种应用，但这种简单快速的萃取技术的潜力和局限性尚未得到充分明确。在这项工作中，确定了 DLLME-SFO 对不同化学家族污染物的萃取效率。研究的化合物包括：10 种多环芳烃、5 种农药（氯苯氧除草剂和滴滴涕）、8 种酚类和 6 种磺胺类，因此涵盖了很大的极性和疏水性范围（LogKow 0-7，总体）。在用 1-十二醇作为萃取剂优化萃取条件后，该方法仅根据需要调整样品 pH 值，即可从 10-mL 加标水样中提取每个家族的物质。LogKow 为 3-7 的污染物的绝对回收率>70%，且该组（18 种化合物）内的回收率值与结构或疏水性无关；回收率的精密度非常可接受（RSD<12%），在所研究的浓度范围内呈线性关系（r(2)>0.995）。LogKow 为 1.46-2.8 的污染物的萃取回收率在 13-62%范围内，直接取决于个别 LogKow 值；然而，尽管回收率水平较低，这些极性溶质也表现出良好的线性（r(2)>0.993）和精密度（RSD<6.5%）。DLLME-SFO 用 1-十二醇完全不能萃取 LogKow≤1 的化合物（磺胺类药物），应探索其他更极性的萃取溶剂（离子液体）来萃取高亲水性污染物。
