Jussila M, Sinervo K, Porras S P, Riekkola M L
Department of Chemistry, University of Helsinki, Finland.
Electrophoresis. 2000 Sep;21(15):3311-7. doi: 10.1002/1522-2683(20000901)21:15<3311::AID-ELPS3311>3.0.CO;2-N.
Electrospray ionization (ESI) is the most widely used ionization method in on-line coupling of capillary electrophoresis-mass spectrometry (CE-MS). The conventional coaxial sheath flow electrospray interface is currently being replaced by the more sensitive nanoelectrospray technique. The usual limitation of nanoelectrospray CE-MS interface has been its short lifetime caused by deterioration of the metal coating on the CE capillary terminus. This article describes an easy way to construct a more durable and sensitive nanospray interface for nonaqueous CE-MS. In this approach a very thin glass spray capillary (ca. 30 microm outer diameter) is partly inserted inside the CE capillary, the junction being surrounded by the electrolyte medium, which is in contact with the platinum electrode. The interface was tested with five pharmaceuticals: methadone, pentazocine, levorphanol, dihydrocodeine, and morphine. Detection limits ranged from 12 to 540 fmol. Separation efficiency and reproducibility were also studied. The CE current was found to be stable and the migration times were highly reproducible. All the CE separations were carried out in a nonaqueous background electrolyte solution.
电喷雾电离（ESI）是毛细管电泳-质谱联用（CE-MS）在线联用中应用最广泛的电离方法。传统的同轴鞘流电喷雾接口目前正被更灵敏的纳米电喷雾技术所取代。纳米电喷雾CE-MS接口通常的局限性在于其CE毛细管末端金属涂层的劣化导致寿命较短。本文介绍了一种为非水CE-MS构建更耐用、更灵敏的纳米喷雾接口的简便方法。在这种方法中，将一根非常细的玻璃喷雾毛细管（外径约30微米）部分插入CE毛细管内，接口处被与铂电极接触的电解质介质包围。用五种药物对该接口进行了测试：美沙酮、喷他佐辛、左啡诺、二氢可待因和吗啡。检测限在12至540飞摩尔之间。还研究了分离效率和重现性。发现CE电流稳定，迁移时间具有高度重现性。所有的CE分离均在非水背景电解质溶液中进行。
