Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan.
J Chromatogr A. 2009 Dec 4;1216(49):8671-5. doi: 10.1016/j.chroma.2009.10.049. Epub 2009 Oct 22.
A liquid-junction/low-flow interface was used to alleviate ion suppression caused by nonvolatile surfactants in micelle electrokinetic chromatography-electrospray ionization-mass spectrometry. Ion suppression due to micelles was alleviated by adjusting operating conditions to keep micelles from entering the ESI source. Two operation modes were investigated. In the first configuration, micelles migrated in the direction opposite to the analytes of interest. A second mode of operation was configured to retain micelles in the liquid-junction between the CE separation column and the ESI interface. In either case, the micelles did not enter the ESI source. To reduce the adverse effect caused by sodium ions, sodium dodecyl sulfate was replaced with the ammonium dodecyl sulfate. Importantly, despite actions taken to alleviate ion suppression, the separation efficiency was preserved as a result of the liquid-junction/low-flow interface. The utility of the described approach for micelle electrokinetic chromatography-electrospray ionization-mass spectrometry was demonstrated by the analysis of sulfonamides at pH 5.5 and pH 7.8, each selected to highlight the two mode of operation.
采用液-接/低流速界面缓解胶束电动色谱-电喷雾电离-质谱中非挥发性表面活性剂引起的离子抑制。通过调节操作条件使胶束不进入电喷雾源来缓解胶束引起的离子抑制。研究了两种操作模式。在第一种配置中，胶束沿与感兴趣的分析物相反的方向迁移。第二种操作模式是将胶束保留在 CE 分离柱和 ESI 接口之间的液-接处。在这两种情况下，胶束都不会进入电喷雾源。为了减少钠离子的不利影响，用十二烷基硫酸铵代替了十二烷基硫酸钠。重要的是，尽管采取了缓解离子抑制的措施，但由于液-接/低流速界面的存在，分离效率得以保持。描述的方法在胶束电动色谱-电喷雾电离-质谱中的应用通过在 pH 5.5 和 pH 7.8 下分析磺胺类药物得到了证明，这两种 pH 值的选择突出了两种操作模式。
