A microfluidic glass chip for performing sensitive mass spectrometry (MS) is developed by integrating nanochannel-based electropreconcentration with electrospray ionization (ESI). Cation analytes in acidic buffer conditions (∼pH 3) were preconcentrated at a micro-nano-microchannel junction where a positively charged polymer, polyE-323, is coated to reverse the electroosmotic flows (anodic EOF) and prevent sample adsorption. The preconcentrated cation analytes were delivered to a monolithic spray tip using an integrated field-free electrokinetic pump, enabling a stable positive ESI with negligible dead volume. The sample preconcentration-ESI-MS achieved one order of magnitude signal enhancement in MS signal with a peptide mixture.

通过将基于纳米通道的电预浓缩技术与电喷雾电离技术（ESI）集成在一起，开发出了一种用于执行灵敏质谱（MS）的微流控玻璃芯片。在酸性缓冲条件（〜pH 3）下的阳离子分析物在微纳微通道连接处进行了预浓缩，在该处涂覆了带正电的聚合物polyE-323，以逆转电渗流（阳极EOF）并防止样品吸附。使用集成的无场电动泵将预浓缩的阳离子分析物输送到整体式喷嘴中，从而获得稳定的正ESI，死体积可忽略不计。样品预浓缩-ESI-MS在使用肽混合物的MS信号中实现了一个数量级的信号增强。