Abstract：
The search for chemical indicators of life is a fundamental component of potential future spaceflight missions to ocean worlds. Capillary electrophoresis (CE) is a useful separation method for the determination of the small organic molecules, such as amino acids and nucleobases, that could be used to help determine whether or not life is present in a sample collected during such missions. CE is under development for spaceflight applications using multiple detection systems, such as laser induced fluorescence (LIF) and mass spectrometry (MS). Here we report CE-based methods for separation and detection of major polar metabolites in cells, such as amino acids, nucleobases/sides, and oxidized and reduced glutathione using detectors that are less expensive alternatives to LIF and MS. Direct UV detection, indirect UV detection, and capacitvely coupled contactless conductivity detection (C4D) were tested with CE, and a combination of direct UV and C4D allowed the detection of the widest variety of metabolites. The optimized method was used to profile metabolites found in samples of Escherichia coli and Pseudoalteromonas haloplanktis and showed distinct differences between the species.
摘要：
寻找生命的化学指标是未来潜在的海洋世界太空飞行任务的基本组成部分。毛细管电泳(CE)是测定有机小分子的一种有用的分离方法,如氨基酸和核碱基，这可用于帮助确定在此类任务中收集的样本中是否存在生命。CE正在开发用于使用多个检测系统的航天应用，如激光诱导荧光(LIF)和质谱(MS)。在这里，我们报告了基于CE的分离和检测细胞中主要极性代谢物的方法，如氨基酸，核碱基/侧，以及氧化和还原的谷胱甘肽，使用的检测器是LIF和MS的廉价替代品。直接紫外检测，间接紫外检测，和电容耦合非接触电导率检测(C4D)进行了测试，直接UV和C4D的组合允许检测最广泛的代谢物。优化后的方法用于对大肠杆菌和假交替单胞菌海洋浮游菌样品中发现的代谢物进行分析，并显示出物种之间的明显差异。
