Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing, 10080, China.
Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.
J Chromatogr A. 2019 May 24;1593:156-163. doi: 10.1016/j.chroma.2019.01.070. Epub 2019 Jan 27.
Nonaqueous capillary electrophoresis (CE) and organic-aqueous CE using high content of organic solvents are common techniques in capillary electrophoresis-mass spectrometry (CE-MS) due to various advantages. However, the long-term stability of commonly used polyimide coated fused silica capillary remains a major problem that polyimide coating is prone to swelling in organic solvents and aminolysis in alkaline buffer, which cause serious problems like irregular electrospray, current drop or clogging event. In this work, robust PEEK capillary was used as separation capillary for tolerance to high content of organic solvents in CE-MS system. It is interesting that the high mechanical and chemical stability of PEEK capillary ensured stable CE separation and electrospray when used in CE-MS. All quantitative experiments were accomplished by single PEEK capillary. In addition, the using of organic solvents as running buffer reduced adsorption of hydrophobic compounds on PEEK capillary wall and improved the symmetry of peak shape. The PEEK-based CE-MS method showed good separation performance in analysis of several groups of active alkaloids in traditional Chinese medicines and was applied for quantitative analysis of peimine and peiminine in Bulbus Fritillariae thunbergii herb with high sensitivity. Based on the advantages like simple pretreatment, easy to cut, stable and good separation performance of PEEK column in CE-MS, this study provides an effective way for improving the stability and employment of high content of organic solvents in CE-MS analysis.
非水毛细管电泳（CE）和高有机溶剂含量的有机-水 CE 是毛细管电泳-质谱（CE-MS）中常用的技术，因为它们具有各种优势。然而，常用的聚酰亚胺涂覆熔融石英毛细管的长期稳定性仍然是一个主要问题，聚酰亚胺涂层在有机溶剂中容易膨胀，在碱性缓冲液中容易发生氨解，这会导致严重的问题，如不规则的电喷雾、电流下降或堵塞事件。在这项工作中，使用了坚固的聚醚醚酮（PEEK）毛细管作为分离毛细管，以耐受 CE-MS 系统中高含量的有机溶剂。有趣的是，PEEK 毛细管的高机械和化学稳定性确保了在 CE-MS 中稳定的 CE 分离和电喷雾。所有定量实验均由单根 PEEK 毛细管完成。此外，使用有机溶剂作为运行缓冲液可以减少疏水性化合物在 PEEK 毛细管壁上的吸附，并改善峰形的对称性。基于 PEEK 的 CE-MS 方法在分析几种中药活性生物碱组方面表现出良好的分离性能，并具有高灵敏度，用于定量分析 Bulbus Fritillariae thunbergii 中的贝母碱和贝母辛。基于 PEEK 柱在 CE-MS 中具有预处理简单、易于切割、稳定和良好的分离性能等优点，本研究为提高 CE-MS 分析中高含量有机溶剂的稳定性和利用率提供了一种有效的方法。
