Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
J Sep Sci. 2011 Apr;34(7):837-43. doi: 10.1002/jssc.201000728. Epub 2011 Feb 18.
In this study, the organochlorine pesticides (OCPs) levels in lake and tap water samples were determined by a dispersive liquid-liquid microextraction method using a low-density organic solvent and an improved solvent collection system (DLLME-ISCS). This method used a very small volume of a solvent of low toxicity (11 μL of 1-nonanol and 400 μL of methanol) to extract OCPs from 10 mL water samples prior to the analysis by GC. After centrifugation in the dispersive liquid-liquid microextraction, there was a liquid organic drop floating between the water surface and the glass wall of the centrifuge tube. The liquid organic drop (with some water phase) was transferred into a microtube (3 mm×15 mm) with a syringe. The organic and aqueous phases were separated in the microtube immediately. Then, 1 μL of the organic solvent (which was in the upper portion of liquid in the microtube) was easily collected by a syringe and injected into the GC-ECD system for the analysis. Under optimum conditions, the linear range of this method was 5-5000 ng/L for most of the analytes. The correlation coefficient was higher than 0.997. Enrichment factors ranged from 1309 to 3629. The relative recoveries ranged from 73 to 119% for lake water samples. The LODs of the method ranged from 0.7 to 9.4 ng/L. The precision of the method ranged from 1.0 to 10.8% for lake water.
在这项研究中，采用分散液液微萃取法（DLLME）结合改进的溶剂收集系统（ISCS），使用低毒性有机溶剂（11 μL 正壬醇和 400 μL 甲醇）从 10 mL 水样中提取有机氯农药（OCPs），并通过 GC 进行分析。在分散液液微萃取中离心后，在离心管的水表面和玻璃壁之间会有一个液体有机液滴漂浮。将含有部分水相的液体有机液滴（LOD）转移到一个 3mm×15mm 的微型管中，用注射器抽取。在微型管中，有机相和水相立即分离。然后，用注射器轻松地从微型管的上部收集 1μL 的有机溶剂，并注入 GC-ECD 系统进行分析。在最佳条件下，该方法对大多数分析物的线性范围为 5-5000ng/L。相关系数均高于 0.997。富集因子范围为 1309-3629。湖水样品的相对回收率为 73-119%。该方法的检出限范围为 0.7-9.4ng/L。湖水的方法精密度范围为 1.0-10.8%。
