Mobility capillary electrophoresis (MCE) was developed previously in our group, which has the capabilities of ion separation and biomolecule hydrodynamic radius analysis. The coupling of MCE with mass spectrometry (MS) would greatly improve complex sample identification capability as well as system detection sensitivity. In the present study, a simple and robust ionization source, named as straight nano-electrospray ionization (nanoESI) source was developed, which was applied to couple MCE with MS. A stainless-steel needle attached directly at the end of an MCE capillary was used as the nanoESI emitter, and the connection between this emitter to the liquid flow in the MCE separation channel was established through a liquid bridge. After optimization, this straight nanoESI source enhanced the ion signal intensity by ~10 times when compared with a commercial nanoESI source. The MCE-straight nanoESI-MS system was also characterized in terms of mixture separation and peptide hydrodynamic radius measurements. Compared to our previous work when a UV detector was used in a commercial Lumex CE system (model Capel 105 M, St. Petersburg, Russia), peptides with much lower concentrations could be analyzed (from ~1 mg/mL to ~20 μg/mL) in terms of radius measurement.

流动毛细管电泳（MCE）是我们小组中较早开发的，具有离子分离和生物分子流体动力学半径分析的功能。MCE与质谱（MS）的结合将大大提高复杂样品的识别能力以及系统检测的灵敏度。在本研究中，开发了一种简单而强大的电离源，称为纯纳米电喷雾电离（nanoESI）源，该源已用于将MCE与MS耦合。直接连接在MCE毛细管末端的不锈钢针用作nanoESI发射器，该发射器与MCE分离通道中的液流之间的连接通过液桥建立。经过优化后，与商用nanoESI源相比，这种直的nanoESI源将离子信号强度提高了约10倍。MCE直nanoESI-MS系统还通过混合物分离和肽流体动力学半径测量进行了表征。与我们以前的工作相比，在商用Lumex CE系统（型号Capel 105 M，俄罗斯圣彼得堡）中使用紫外检测器时，可以分析浓度低得多的肽（从〜1 mg / mL到〜20μg/半径测量值）。