INM - Leibniz Institute for New Materials, Campus D2-2, D-66123, Saarbrücken, Germany.
INM - Leibniz Institute for New Materials, Campus D2-2, D-66123, Saarbrücken, Germany; Department of Physics, Saarland University, Campus D2-2, D-66123, Saarbrücken, Germany.
Micron. 2021 Oct;149:103109. doi: 10.1016/j.micron.2021.103109. Epub 2021 Jun 30.
Graphene liquid cells (GLCs) present the thinnest possible sample enclosures for liquid phase electron microscopy. However, the actual presence of liquid within a GLC is not always guaranteed. Of key importance is to reliably test the presence of the liquid, which is most frequently water or saline. Here, the commonly used methods for verifying the presence of water were evaluated. It is shown that depending on the type of sample, applying a single criterion does not always conclusively verify the presence of water. Testing liquid filling for a specific GLC sample preparation protocol should thus be considered critically. The most reliable method is direct observation of the water exciton peak using electron energy loss spectroscopy (EELS). But if this method cannot be carried out, water filling of the GLC can be verified from a combination of higher contrast in the image, the presence of bubbles, and an oxygen signal in the EEL spectrum, which can be accomplished at a high electron dose in spot mode. Nanoparticle movement does not always occur in a GLC.
石墨烯液相池（GLC）为液相电子显微镜提供了尽可能薄的样品封装。然而，GLC 内液体的实际存在并不总是有保证的。至关重要的是要可靠地测试液体的存在，而液体通常是水或盐水。本文评估了常用的验证水存在的方法。结果表明，取决于样品的类型，应用单一标准并不总是能明确验证水的存在。因此，应严格考虑针对特定 GLC 样品制备方案的液体填充测试。最可靠的方法是使用电子能量损失光谱（EELS）直接观察水激子峰。但是，如果无法进行此方法，可以从图像中更高的对比度、气泡的存在以及 EEL 光谱中的氧信号的组合来验证 GLC 中的水填充，这可以在高电子剂量的点模式下完成。纳米颗粒的运动并不总是在 GLC 中发生。
