This paper describes the availability of a 1,2-dichloroethane (DCE)-water (W) interfacial system under a controlled interfacial potential difference for the separation of polycationic species. The system was applied to the production of polyethylene glycol-modified ε-poly-L-lysine (PEG-εPL). PEG-εPL is produced by a fermentation process, and the crude product contains a significant amount of non-modified εPL, which is hardly separated by conventional chromatographic techniques. Both εPL species exist in fully protonated forms under certain acidic conditions, and an extractant, dibenzo-18-crown-6 (DB18C6), associates with their ammonium groups to stabilize the polycations in DCE. Despite the polydispersity of the samples, the εPL and crude PEG-εPL give well-defined cyclic voltammetric waves due to the DB18C6-assisted transfer of the polycations at the polarizable DB18C6 (DCE) | (W, pH ~ 3) interface with midpoint potentials useful for a rough prediction of ion partition equilibria. Thus, the partition experiment was performed using the DB18C6, Bu4N[(CF3SO2)2N] (DCE) | crude PEG-εPL, Li[(CF3SO2)2N] (W, pH ~ 3) interfacial system, of which the potential difference was controlled to enable selective extraction of polycationic PEG-εPL by partition of the [(CF3SO2)2N]- ion. The extract could be collected from the DCE phase and was found to consist of highly purified PEG-εPL.

中文翻译：

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在受控界面电位差下通过溶剂萃取分离 ε-聚-L-赖氨酸衍生物。

本文描述了在受控界面电位差下 1,2-二氯乙烷 (DCE)-水 (W) 界面系统用于分离聚阳离子物质的可用性。该系统应用于聚乙二醇修饰ε-聚-L-赖氨酸（PEG-εPL）的生产。PEG-εPL是通过发酵工艺生产的，粗产物中含有大量未修饰的εPL，传统的色谱技术很难将其分离。两种 εPL 物质在某些酸性条件下均以完全质子化的形式存在，并且萃取剂二苯并-18-冠-6 (DB18C6) 与其铵基结合以稳定 DCE 中的聚阳离子。尽管样品具有多分散性，由于 DB18C6 辅助聚阳离子在可极化 DB18C6 (DCE) 处的转移，εPL 和粗 PEG-εPL 给出了明确的循环伏安波。(W, pH ~ 3) 具有中点电位的界面可用于粗略预测离子分配平衡。因此，使用 DB18C6, Bu4N[(CF3SO2)2N] (DCE) | 进行分配实验。粗制PEG-εPL，Li[(CF3SO2)2N] (W, pH ~ 3)界面体系，控制其电位差，通过[(CF3SO2)2N]-离子的分配选择性萃取聚阳离子PEG-εPL 。可以从 DCE 相中收集提取物，并发现提取物由高度纯化的 PEG-εPL 组成。