Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, SC 88040-900, Brazil.
Talanta. 2011 May 15;84(3):989-94. doi: 10.1016/j.talanta.2011.03.002. Epub 2011 Mar 29.
A novel hollow-fiber liquid-liquid-solid micro-extraction technique based on simultaneous liquid-liquid micro-extraction and solid phase micro-extraction using a polypropylene microporous membrane has been developed. The applicability of the proposed procedure was evaluated by extraction of Pb(II) from aqueous solutions and soft drinks. The parameters affecting the extraction efficiency were optimized using multivariate methodology, and the analytical features were established. Under optimized conditions, Pb(II) was concentrated for 20 min on three microporous membrane hollow fibers of 6mm of length each, placed into 20 mL of sample containing 60 μL of toluene and ammonium O,O-diethyl dithiophosphate. The fibers were introduced directly into the graphite furnace as a solid sample, and the analyte was thermally desorbed from the fiber and atomized using ruthenium as a permanent modifier. A detection limit of 7 ng L(-1) Pb was obtained for soft drink samples and good repeatability was found for all samples. The enrichment factor varied between 22 and 66, depending if only one or all three hollow fibers were used for the determination of lead. The results suggest that the proposed procedure represents a simple and low-cost micro-extraction alternative rendering adequate limits of quantification for the determination of Pb(II) in soft drink samples.
一种基于同时液-液微萃取和固相微萃取的新型中空纤维液-固微萃取技术，使用了一种聚丙烯微孔膜。通过从水溶液和软饮料中萃取 Pb(II)，评估了该方法的适用性。使用多元方法优化了影响萃取效率的参数，并建立了分析特征。在优化条件下，将 Pb(II)在三根长 6mm 的微孔膜中空纤维上浓缩 20 分钟，每根纤维放入 20mL 含有 60μL 甲苯和铵 O,O-二乙基二硫代磷酸的样品中。纤维直接作为固体样品引入石墨炉中，用钌作为永久改性剂从纤维中热解吸并原子化分析物。对于软饮料样品，获得了 7ng L(-1)Pb 的检测限，并且所有样品的重复性都很好。富集因子在 22 到 66 之间变化，具体取决于仅使用一根或三根中空纤维来测定铅。结果表明，该方法简单、成本低，是一种软饮料样品中 Pb(II)测定的替代方法，具有足够的定量限。
