Institute of Chemistry, Tallinn University of Technology, Akadeemia Tee 15, Tallinn, Estonia.
J Chromatogr A. 2012 Apr 20;1234:9-15. doi: 10.1016/j.chroma.2011.12.052. Epub 2011 Dec 23.
Present article describes a novel technique based on digital microfluidics that allows collecting fractions of interest after electrophoretic separation and detection for further ESI-MS investigation. In this technique, a mixture is injected into a capillary electrophoresis (CE) apparatus, and microliter droplets are generated at the CE outlet at a frequency high enough to fraction each compound into several droplets, compartmentalizing the CE zones into a sequence of droplets. The droplets are transported from the CE outlet to a storage tube inlet using electrowetting-on-dielectric (EWOD) for droplet actuation. By applying a vacuum at the other end of the storage tube, the droplets form a sequence of plugs separated by air gaps. The plugs stored in the tubing are later analyzed using a standalone spectrometric device. Off-line electrospray ionization mass spectrometry (ESI-MS) was used to characterize the corresponding vitamin and was performed by pumping the segmented plugs directly into a spray emitter tip. The technique could be of interest to laboratories without access to well-equipped facilities (e.g. clean-rooms or lab robots).
本文介绍了一种基于数字微流控的新技术，该技术允许在电泳分离和检测后收集感兴趣的馏分，以便进一步进行 ESI-MS 研究。在该技术中，将混合物注入毛细管电泳 (CE) 装置中，并以足够高的频率在 CE 出口处生成微升液滴，将 CE 区分成多个液滴，将 CE 区分成一系列液滴。使用基于介电上电润湿 (EWOD) 的方法使液滴从 CE 出口传输到储存管入口，以实现液滴的驱动。通过在储存管的另一端施加真空，液滴形成一系列由气隙隔开的塞子。在管中储存的塞子以后使用独立的分光计设备进行分析。离线电喷雾电离质谱 (ESI-MS) 用于对相应的维生素进行特征分析，并通过将分段塞子直接泵入喷雾发射器尖端来完成。该技术对于没有配备齐全设备（例如洁净室或实验室机器人）的实验室可能具有吸引力。
