Kubáň Pavel, Boček Petr
Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Veveří 97, 60200 Brno, Czech Republic.
Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i., Veveří 97, 60200 Brno, Czech Republic.
Anal Chim Acta. 2014 Oct 27;848:43-50. doi: 10.1016/j.aca.2014.07.037. Epub 2014 Aug 1.
Preconcentration potential of micro-electromembrane extraction (μ-EME) across free liquid membrane (FLM) was examined with an anionic and a cationic dye, 4,5-dihydroxy-3-(p-sulfophenylazo)-2,7-naphthalene disulfonic acid, trisodium salt (SPADNS) and phenosafranine, respectively. For the first time, it was shown that the spatial flexibility of FLMs enabled application of tailored extraction units with mutually different shapes and migration cross-sections for FLMs, donor and acceptor solutions. Thus, e.g. conical units enabled easy and reproducible formation of a three-phase extraction system (donor/FLM/acceptor) with sub-μL volumes of acceptor solutions as well as rapid and highly efficient preconcentration of the two dyes. Quantitative measurements of resulting solutions were carried out by UV-vis spectrophotometry and enrichment factors of up to 98 were achieved for μ-EMEs of 20 μM SPADNS (50 μL) preconcentrated into 0.5 μL of pure water across 1-pentanol at -150 V for 18 min. Visual monitoring of the entire extraction process (with USB microscope camera) was possible across transparent extraction units, moreover, important extraction parameters, such as FLM dimensions and donor-to-acceptor solution volume ratio, which determine the mechanical stability of the membrane and maximum enrichment factor, respectively, were readily adjusted. Combination of μ-EME across FLMs with capillary electrophoresis (CE) was further shown suitable for preconcentration and determination of perchlorate in drinking water samples. Good repeatability of the μ-EME-CE method (RSD values better than 9.5%), linear relationship for the analytical signal vs. concentration (r(2) better than 0.997) and enrichment factors of up to 30 were achieved for μ-EMEs of perchlorate across 1-pentanol and 1-hexanol based FLMs.
分别使用阴离子染料和阳离子染料，即4,5 - 二羟基 - 3 -（对磺基苯偶氮）- 2,7 - 萘二磺酸三钠盐（SPADNS）和番红，研究了微电膜萃取（μ-EME）跨自由液膜（FLM）的预富集潜力。首次表明，自由液膜的空间灵活性使得能够应用具有相互不同形状和迁移横截面的定制萃取单元，用于自由液膜、供体溶液和受体溶液。例如，锥形单元能够轻松且可重复地形成三相萃取系统（供体/自由液膜/受体），受体溶液体积为亚微升，同时能快速高效地预富集这两种染料。通过紫外 - 可见分光光度法对所得溶液进行定量测量，对于将20 μM SPADNS（50 μL）在 - 150 V下通过1 - 戊醇预富集到0.5 μL纯水中18分钟的μ-EME，富集因子高达98。通过透明萃取单元可以（使用USB显微镜摄像头）对整个萃取过程进行视觉监测，此外，重要的萃取参数，如自由液膜尺寸和供体与受体溶液体积比，分别决定了膜的机械稳定性和最大富集因子，易于调节。还表明跨自由液膜的μ-EME与毛细管电泳（CE）相结合适用于饮用水样品中高氯酸盐的预富集和测定。对于基于1 - 戊醇和1 - 己醇的自由液膜的高氯酸盐μ-EME，μ-EME - CE方法具有良好的重复性（相对标准偏差值优于9.5%），分析信号与浓度呈线性关系（r(2)优于0.997），富集因子高达30。
