A novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s^1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 μL samples could be done within 3.6 min or effectively 15.3 s per sample.

通过集成微流体技术和微核磁共振共振器，实现了一种具有改进质量灵敏度的自动化高通量核磁共振光谱的新方法。流动系统用于从 NMR 磁体外部通过 NMR 检测器传输感兴趣的样品，通过加载一系列由不混溶流体隔开的单独样品塞来绕过供应管中相对较大的死体积。这种双相流需要一个实时稳健的传感系统来跟踪样品位置和速度并同步 NMR 采集。在这篇文章中，我们描述了一个具有微流体系统的 NMR 探头，其特点是：(i) 用于 NMR 光谱的微型鞍形线圈和 (ii) 一对叉指式电容传感器，位于 NMR 检测器的两侧，用于相对于 NMR 检测器对塞子进行连续位置和速度监测。该系统在 500 MHz NMR 系统中成功地进行了基于流动的自动测量测试，实现了高分辨率光谱和 2.18 nmol s 的 NMR 灵敏度^1/2流量传感器在运行。流量传感器对相对介电常数的绝对差为 0.2 具有灵敏度，从而能够区分最常见的溶剂。结果表明，可以在 3.6 分钟内或每个样品有效 15.3 秒内对九个单独的 120 μL 样品进行全自动 NMR 测量。