Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
Lab Chip. 2020 Aug 26;20(17):3202-3212. doi: 10.1039/d0lc00364f.
Combining microfluidic devices with nuclear magnetic resonance (NMR) has the potential of unlocking their vast sample handling and processing operation space for use with the powerful analytics provided by NMR. One particularly challenging class of integrated functional elements from the perspective of NMR are conductive structures. Metallic electrodes could be used for electrochemical sample interaction for example, yet they can cause severe NMR spectral and SNR degradation. These issues are more entangled at the micro-scale since the distorted volume occupies a higher ratio of the sample volume. In this study, a combination of simulation and experimental validation was used to identify an electrode geometry that, in terms of NMR spectral parameters, performs as well as for the case when no electrodes are present. By placing the metal tracks in the side-walls of a microfluidic channel, we found that NMR RF excitation performance was actually enhanced, without compromising B0 homogeneity. Monitoring in situ deposition of chitosan in the microfluidic platform is presented as a proof-of-concept demonstration of NMR characterisation of an electrochemical process.
将微流控设备与核磁共振（NMR）相结合，有可能为 NMR 提供的强大分析能力，开辟其广泛的样本处理和操作空间。从 NMR 的角度来看，导电结构是一类特别具有挑战性的集成功能元件。例如，金属电极可用于电化学样品相互作用，但它们会导致严重的 NMR 光谱和 SNR 降级。由于失真体积在样品体积中占比更高，因此在微尺度上这些问题更加复杂。在本研究中，通过模拟和实验验证相结合，确定了一种电极几何形状，就 NMR 光谱参数而言，其性能与没有电极时一样好。通过将金属轨道放置在微流道的侧壁中，我们发现 NMR RF 激发性能实际上得到了增强，同时没有影响 B0 均匀性。本文还展示了在微流控平台中实时监测壳聚糖的原位沉积，以此作为电化学过程的 NMR 特性的概念验证演示。
