We report a new approach for forming ion depletion zones (IDZs) using intercalation reactions at an electrochemically controlled Prussian blue (PB) film. The experiments described here were performed using a microfluidic device, wherein a charged fluorophore in solution was used as a proxy to monitor IDZ formation. In the presence of K⁺, intercalation reactions proceed readily to form an IDZ, and thus enrich the fluorophore up to 37‐fold. In the presence of the larger hydrated Li⁺ or tetrabutylammonium (TBA⁺) ions, however, ion intercalation proceeded less quickly than with K⁺. Slower ion intercalation resulted in a weaker IDZ and correspondingly lower enrichment factors of eight‐ and six‐fold, respectively. These results are significant because they show that PB intercalation reactions selectively form an IDZ. Accordingly, we anticipate that these findings will lead to a better understanding and further interesting applications of intercalation materials like PB for efficient and selective enrichment and separations.

中文翻译：

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使用普鲁士蓝插层反应对阳离子进行电动分离

我们报告了一种在电化学控制的普鲁士蓝（PB）膜上使用插层反应形成离子耗尽区（IDZ）的新方法。这里描述的实验是使用微流体装置进行的，其中溶液中带电的荧光团被用作代理来监测IDZ的形成。在存在K ⁺的情况下，插入反应易于形成IDZ，从而使荧光团最多富集37倍。但是，在存在较大的水合Li ⁺或四丁基铵（TBA ⁺）离子的情况下，离子嵌入的进行速度不如K ⁺快。较慢的离子嵌入会导致IDZ变弱，并且相应的富集系数会降低八倍和六倍。这些结果很重要，因为它们表明PB嵌入反应选择性地形成了IDZ。因此，我们预期这些发现将导致更好地了解和进一步有趣地应用插层材料（如PB）来进行有效和选择性的富集和分离。