Koerner Terry, Oleschuk Richard D
Department of Chemistry, Queen's University, Kingston, Ontario, Canada, K7L 3N6.
Rapid Commun Mass Spectrom. 2005;19(22):3279-86. doi: 10.1002/rcm.2181.
The coupling of a lab-on-a-chip microfluidic device to a nanoelectrospray ionization mass spectrometer has the potential to automate many routine analytical procedures and produce a powerful analytical tool. However, past coupling strategies have relied on complex manufacturing steps including drilling and etching the device to attach a capillary or building a nanospray emitter directly into the device. This study shows that a nanospray emitter can be easily fabricated using a porous polymer monolith (PPM) at the end of a glass microdevice. These devices are able to obtain a stable electrospray at a variety of flow rates (50-500 nL/min) but optimal results are obtained at lower flow rates (50-100 nL/min) compatible with electroosmotic flow processes. The PPM is photo-patterned so that it can be placed in any position within the channel of the device with no dead volume. The porous character and the hydrophobic nature of the PPM both aid in development of a stable electrospray process. Total ion current traces for the constant infusion of leucine-enkephalin and PPG show relative standard errors as low as 4%, and produce mass spectra with good signal-to-noise (S/N 43) from only 2 fmol of material. In addition, multiple experiments in a given day show good repeatability with variability as low as 13%, and the multiple flow paths inherent in the PPM limit sprayer clogging.
将芯片实验室微流控装置与纳米电喷雾电离质谱仪联用，有潜力实现许多常规分析程序的自动化，并打造出一种强大的分析工具。然而，过去的联用策略依赖于复杂的制造步骤，包括对装置进行钻孔和蚀刻以连接毛细管，或者直接在装置中构建纳米喷雾发射器。本研究表明，可在玻璃微装置末端使用多孔聚合物整体柱（PPM）轻松制造纳米喷雾发射器。这些装置能够在多种流速（50 - 500纳升/分钟）下获得稳定的电喷雾，但在与电渗流过程兼容的较低流速（50 - 100纳升/分钟）下可获得最佳结果。PPM通过光刻图案化，因此可以放置在装置通道内的任何位置，且无死体积。PPM的多孔特性和疏水性质都有助于稳定电喷雾过程的发展。亮氨酸脑啡肽和聚丙二醇连续注入时的总离子流曲线显示相对标准误差低至4%，仅2飞摩尔的物质就能产生具有良好信噪比（S/N 43）的质谱图。此外，在给定的一天内进行的多次实验显示出良好的重复性，变异性低至13%，并且PPM固有的多个流动路径限制了喷雾器堵塞。
