Gjelstad Astrid, Rasmussen Knut Einar, Pedersen-Bjergaard Stig
School of Pharmacy, University of Oslo, Oslo, Norway.
J Chromatogr A. 2007 Dec 7;1174(1-2):104-11. doi: 10.1016/j.chroma.2007.08.057. Epub 2007 Aug 30.
The present work has for the first time described and verified a theoretical model of the analytical extraction process electro-membrane extraction (EME), where target analytes are extracted from an aqueous sample, through a thin layer of 2-nitrophenyl octylether immobilized as a supported liquid membrane (SLM) in the pores in the wall of a porous hollow fibre, and into an acceptor solution present inside the lumen of the hollow fibre by the application of an electrical potential difference. The mathematical model was based on the Nernst-Planck equation, and described the flux over the SLM. The model demonstrated that the magnitude of the electrical potential difference, the ion balance of the system, and the absolute temperature influenced the flux of analyte across the SLM. These conclusions were verified by experimental data with five basic drugs. The flux was strongly dependent of the potential difference over the SLM, and increased potential difference resulted in an increase in the flux. The ion balance, defined as the sum of ions in the donor solution divided by the sum of ions in the acceptor solution, was shown to influence the flux, and high ionic concentration in the acceptor solution relative to the sample solution was advantageous for high flux. Different temperatures also led to changes in the flux in the EME system.
本研究首次描述并验证了分析萃取过程——电膜萃取（EME）的理论模型。在该模型中，目标分析物从水样中通过固定在多孔中空纤维壁孔内作为支撑液膜（SLM）的2-硝基苯基辛醚薄层进行萃取，并通过施加电势差进入中空纤维内腔中的接受液。该数学模型基于能斯特-普朗克方程，描述了通过支撑液膜的通量。该模型表明，电势差的大小、系统的离子平衡以及绝对温度会影响分析物通过支撑液膜的通量。这些结论通过五种碱性药物的实验数据得到了验证。通量强烈依赖于支撑液膜上的电势差，电势差增加会导致通量增加。离子平衡定义为供体溶液中离子总和除以接受液中离子总和，结果表明其会影响通量，接受液中相对于样品溶液的高离子浓度有利于高通量。不同温度也会导致电膜萃取系统中通量的变化。
