Michalke B, Schramel P
National Research Center for Environment and Health Institute of Ecological Chemistry, Neuherberg, Germany.
Electrophoresis. 1998 Feb;19(2):270-5. doi: 10.1002/elps.1150190221.
The high resolution potential of capillary electrophoresis (CE) makes CE techniques valuable for separations of selenium species. Further, inductively coupled plasma-mass spectrometry (ICP-MS) affords element-specific multi-element detection, providing extremely low detection limits. The combination of CE with ICP-MS promises to become a powerful tool for metal speciation. Therefore, an on-line hyphenation of CE with ICP-MS, which was developed earlier (Michalke, B., Schramel, P., Fresenius' J. Anal. Chem. 1997, 257, 594-599), was modified and applied to selenium speciation. For this reason, capillary zone electrophoresis (CZE) methods were developed, providing the possibility to analyze six Se species of interest in one run: Se (IV), Se (VI), selenium carrying glutathione (GSSeSG), selenomethionine (SeM), selenocystine (SeC), and selenocystamine (SeCM). The final CE method used an alkaline background electrolyte (Na2CO3/NaOH) with separation differentiated from the detection step during hyphenation. This resulted in short separation times (10 min) and a subsequent detection step of 100s. The Se species were sufficiently separated from each other and appeared at 7s (SeCM), 16s (Se [VI]), 22s [SeC], 27s (Se [IV]), 35s [SeM] and 56s (GSSeSG) during the detection step. Detection limits were calculated as 10 or 20 microg Se/L for inorganic Se species and 35-50 microg Se/L for organic Se species.
毛细管电泳（CE）的高分辨率潜力使CE技术在硒形态分离方面具有重要价值。此外，电感耦合等离子体质谱（ICP-MS）可实现元素特异性多元素检测，检测限极低。CE与ICP-MS联用有望成为金属形态分析的强大工具。因此，对早期开发的CE与ICP-MS在线联用技术（Michalke, B., Schramel, P., Fresenius' J. Anal. Chem. 1997, 257, 594 - 599）进行了改进，并应用于硒形态分析。为此，开发了毛细管区带电泳（CZE）方法，能够在一次运行中分析六种感兴趣的硒形态：硒（IV）、硒（VI）、谷胱甘肽携带的硒（GSSeSG）、硒代蛋氨酸（SeM）、硒代胱氨酸（SeC）和硒代半胱胺（SeCM）。最终的CE方法使用碱性背景电解质（Na2CO3/NaOH），在联用过程中分离与检测步骤区分开来。这使得分离时间较短（10分钟），随后的检测步骤为100秒。在检测步骤中，硒形态彼此充分分离，分别在7秒（SeCM）、16秒（硒[VI]）、22秒[SeC]、27秒（硒[IV]）、35秒[SeM]和56秒（GSSeSG）出现。无机硒形态的检测限计算为10或20微克硒/升，有机硒形态的检测限为35 - 50微克硒/升。
