Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, vvi, Brno, Czech Republic.
J Chromatogr A. 2012 Dec 7;1267:96-101. doi: 10.1016/j.chroma.2012.07.010. Epub 2012 Jul 13.
Monitoring the selectivity of supported liquid membranes (SLMs) is of paramount importance since the amount and type of compounds that are transferred across a SLM directly influence the transfer efficiency, reproducibility and accuracy. To apply a correct SLM in particular sample pretreatment, rapid determination of the transfer of analytes and matrix compounds across the SLM is necessary, which requires the use of an analytical method with universal detection technique. Capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4)D) has proven to be a useful tool for the determination of SLM selectivity. Background electrolyte solution consisting of 1M acetic acid (pH 2.4) was used for simultaneous separation and detection of three basic drugs (nortriptyline, haloperidol and loperamide) and major matrix components (inorganic cations, proteins, amino acids, etc.) after electromembrane extraction (EME) of standard solutions and complex samples. The CE-C(4)D method has evidenced for the first time that large proteins, such as human serum albumin, are efficiently retained on all examined SLMs and that transfer of other matrix components and the analytes is strongly SLM dependent. Excellent transfer of the analytes was achieved across SLMs impregnated with 2-nitrophenyl octyl ether (NPOE) or 1-ethyl-2-nitrobenzene, however, an increased co-extraction of interfering matrix components, which disabled quantitative determination of haloperidol with the current CE-C(4)D setup, was observed for the latter. After addition of a commonly used ion carrier (bis(2-ethylhexyl)phosphate) to NPOE, a wide range of matrix components were transferred across the SLM with no measurable transfer of the analytes. Best selectivity regarding transfer of the basic drugs and elimination of matrix components was obtained using SLM impregnated with NPOE. An optimized EME-CE-C(4)D method was used to determine the basic drugs in various samples and satisfactory analytical parameters were obtained.
监测支撑液膜（SLM）的选择性至关重要，因为穿过 SLM 的化合物的数量和类型直接影响转移效率、重现性和准确性。为了在特定的样品预处理中应用正确的 SLM，需要快速测定分析物和基质化合物穿过 SLM 的转移情况，这需要使用具有通用检测技术的分析方法。使用 1M 乙酸（pH 2.4）作为背景电解质溶液，通过毛细管电泳与电容耦合非接触电导检测（CE-C(4)D）可以同时分离和检测三种碱性药物（去甲替林、氟哌啶醇和洛哌丁胺）以及主要基质成分（无机阳离子、蛋白质、氨基酸等），这是在标准溶液和复杂样品进行电膜萃取（EME）之后进行的。CE-C(4)D 方法首次证明，大蛋白，如人血清白蛋白，可有效地被所有检查的 SLM 保留，而其他基质成分和分析物的转移则强烈依赖于 SLM。通过浸渍 2-硝基苯基辛基醚（NPOE）或 1-乙基-2-硝基苯的 SLM 可以实现分析物的有效转移，然而，在后一种情况下，观察到干扰基质成分的共萃取增加，这使得使用当前的 CE-C(4)D 装置无法对氟哌啶醇进行定量测定。在 NPOE 中加入常用的离子载体（双（2-乙基己基）磷酸酯）后，基质成分可以在 SLM 中广泛转移，而分析物则没有可测量的转移。使用浸渍有 NPOE 的 SLM 可以获得最佳的碱性药物转移选择性和基质成分消除效果。优化后的 EME-CE-C(4)D 方法用于测定各种样品中的碱性药物，获得了令人满意的分析参数。
