Liu Jing-Fu, Toräng Lars, Mayer Philipp, Jönsson Jan Ake
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
J Chromatogr A. 2007 Aug 10;1160(1-2):56-63. doi: 10.1016/j.chroma.2007.04.010. Epub 2007 Apr 13.
Hollow fiber supported liquid membranes were applied for the passive extraction of phenoxy acid herbicides from water samples. Polypropylene hollow fiber membranes (240 microm i.d., 30 microm wall thickness, 0.05 microm pore size, 30 cm length) were impregnated with 2.0% tri-n-octylphosphine oxide (TOPO) in di-n-hexyl ether in the pores of the fiber wall to form a liquid membrane. They were then filled with basic solution in the lumen as acceptor and finally placed into the sample (donor). Complete extraction of phenoxy acid herbicides including 2,4-D, MCPA, dichlorprop, and mecoprop from an acidified sample (4 mL, adjusted to pH 1.5 with HCl) into basic acceptor (10 microL of 0.2M NaOH) was achieved after 4 h of shaking (100 rpm) resulting in an enrichment factor of 400 times. The acceptor was then neutralized by addition of HCl and injected into a HPLC system for the determination of the phenoxy acid herbicides. Environmentally relevant salinity (0-3.5% NaCl) and dissolved organic matter (0-25 mg/L of dissolved organic carbon) had no significant effect on the extraction. The method provided extraction efficiencies of more than 91%, detection limits of 0.3-0.6 microg/L, and combined extraction and clean up in one single step. This procedure was applied to determine aqueous concentrations of phenoxy acid herbicides in groundwater samples collected from an old dumping site (Cheminova, Denmark) with detected concentrations up to 5800 microg/L. Although the samples were very dirty with large amounts of suspended particles, non-aqueous phase liquids (NAPLs) and dissolved organic matters, good spike recoveries (80-126%) were obtained for 10 of the 11 samples.
中空纤维支撑液膜被用于从水样中被动萃取苯氧羧酸类除草剂。将聚丙烯中空纤维膜（内径240微米，壁厚30微米，孔径0.05微米，长度30厘米）在纤维壁的孔隙中用2.0%三正辛基氧化膦（TOPO）的二正己醚溶液浸渍以形成液膜。然后在膜腔内填充碱性溶液作为接受相，最后将其置于样品（供体）中。在以100转/分钟振荡4小时后，可实现将包括2,4 - D、MCPA、二氯丙酸和甲羧除草醚在内的苯氧羧酸类除草剂从酸化样品（4毫升，用盐酸调节至pH 1.5）完全萃取到碱性接受相（10微升0.2M氢氧化钠）中，富集倍数达400倍。接着通过加入盐酸使接受相中和，然后注入高效液相色谱系统以测定苯氧羧酸类除草剂。环境相关盐度（0 - 3.5%氯化钠）和溶解有机物（0 - 25毫克/升溶解有机碳）对萃取没有显著影响。该方法的萃取效率超过91%，检测限为0.3 - 0.6微克/升，且在一步操作中实现了萃取和净化。该程序被用于测定从一个旧垃圾场（丹麦Chemnova）采集的地下水样品中苯氧羧酸类除草剂的水相浓度，检测到的浓度高达5800微克/升。尽管样品非常脏，含有大量悬浮颗粒、非水相液体（NAPLs）和溶解有机物，但11个样品中的10个获得了良好的加标回收率（80 - 126%）。
