Kim Jihye, Choi Kihwan, Chung Doo Soo
Department of Chemistry, Seoul National University, Seoul, 151-747, South Korea.
Division of Methodology for Quality of Life, Korea Research Institute of Standards and Science, Daejeon, 305-340, South Korea.
Anal Bioanal Chem. 2015 Nov;407(29):8745-52. doi: 10.1007/s00216-015-9028-0. Epub 2015 Sep 24.
Single-drop microextraction (SDME) was in-line coupled with capillary electrophoresis-mass spectrometry to provide sample cleanup and enrichment simultaneously. Since there is no outlet vial in a conventional capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) configuration, it is not easy to hang a single drop in the capillary inlet for extraction. We overcame the difficulty of coupling SDME and CE-MS by using a temporary outlet reservoir. Basic drugs such as methamphetamine, amphetamine, phenethylamine, methoxyphenamine, and mephentermine were extracted from a basic sample solution to an acidic acceptor drop covered with a thin octanol layer formed at the capillary inlet tip. Compared to the CE-MS method in the multiple reaction monitoring (MRM) mode, the in-line SDME-CE-MS/MS technique showed 130∼150-fold enrichment in 10 min. The relative standard deviations (RSDs) of peak height ranged from 9 to 13 %. RSDs can be reduced from 4 to 6 % using mephentermine as an internal standard. We examined the pretreatment of sample with and without SDME from human urine under the full-scan mode, which confirmed that many metabolites were cleaned up by the selective extraction method of SDME. Even if the analytes from human urine were analyzed under the MRM mode used as a mass filter, there was an isobaric compound causing a disturbance to the analysis. However, in-line SDME-CE-MS/MS made it possible to perform a sample cleanup as well as sample enrichment. The research is extremely advantageous in that it is rapid, convenient, and highly sensitive for the analysis of biological samples using a commercially available instrument.
单滴微萃取（SDME）与毛细管电泳-质谱联用，可同时实现样品净化和富集。由于传统的毛细管电泳-电喷雾电离-质谱（CE-ESI-MS）配置中没有出口瓶，因此在毛细管入口处悬挂一滴用于萃取并不容易。我们通过使用临时出口储液器克服了将SDME与CE-MS联用的困难。从碱性样品溶液中萃取甲基苯丙胺、苯丙胺、苯乙胺、甲氧苯丙胺和美芬丁胺等碱性药物，使其进入覆盖在毛细管入口尖端形成的薄辛醇层的酸性接受液滴中。与多反应监测（MRM）模式下的CE-MS方法相比，在线SDME-CE-MS/MS技术在10分钟内实现了130至150倍的富集。峰高的相对标准偏差（RSD）范围为9%至13%。以美芬丁胺为内标，RSD可从4%降至6%。我们在全扫描模式下研究了有无SDME时人尿样品的预处理，证实了许多代谢物通过SDME的选择性萃取方法得到了净化。即使在用作质量过滤器的MRM模式下分析人尿中的分析物，也存在一种等压化合物对分析造成干扰。然而，在线SDME-CE-MS/MS使样品净化和富集成为可能。该研究具有极大的优势，即使用市售仪器对生物样品进行分析时快速、方便且高度灵敏。
