Capillary Electrophoresis System for Water Quality Analyses and Interpretations in the Undergraduate Geochemistry Laboratory

毛细管电泳（CE）系统的收购使自然水样中溶解的无机和有机阴离子的分析。溶解的阴离子进行常规分析，以评估水质，补充溶解的阳离子的分析，电感耦合等离子体原子发射光谱法（ICP-AES）的方法。这些数据是了解天然水成分的地球化学过程，包括水-岩相互作用，污染物迁移和碳循环的基础。 水中溶解阴离子的分析通常使用离子交换色谱法完成。然而，最近的应用CE方法的水样呈现出许多优势，离子交换方法，特别是在学术环境。CE系统具有更少的移动部件、更便宜的色谱柱、更小的溶剂废物量和更快的分析速度。 在地球化学导论课程中的高级本科地质学专业正在指导含水地球化学的概念（例如，平衡，活性和浓度关系以及矿物溶解度）。这些概念可用于了解自然（和可能受污染的）地下水和地表水样本的控制过程。学生通过六部分的练习，他们执行以下任务：在现场收集水样;准备水样进行分析;通过CE分析样品的阴离子;通过ICP-AES分析样品的溶解阳离子;通过图形方法对水质数据进行定性解释;并通过计算机模型对水质数据进行定量解释。 除了在本科阶段提供跨学科的教育和研究机会外，获得CE还增强了该部门开发本科实验室练习的能力，重点是水质分析。

The acquisition of a capillary electrophoresis (CE) system enables analyses of dissolved inorganic and organic anions in natural water samples. Dissolved anions are analyzed routinely to assess water quality, supplementing the analysis of dissolved cations by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) methods. These data are fundamental to an understanding of natural water compositions in the context of geochemical processes including water-rock interactions, contaminant migration, and carbon cycling. Analysis of dissolved anions in water is commonly accomplished using ion-exchange chromatography. However, recent application of CE methods to water samples presents many advantages over ion-exchange methods, especially in an academic setting. CE systems have fewer moving parts, less expensive columns, smaller solvent waste volumes, and faster analyses. Upper-level undergraduate geology majors in the Introduction to Geochemistry course are being instructed in the concepts of aqueous geochemistry (for example, equilibrium, activity and concentration relationships, and mineral solubility). These concepts can be applied in order to understand the processes governing natural (and possibly contaminated) ground and surface water samples. Students proceed through a six-part exercise in which they perform the following tasks: collect water samples in the field; prepare water samples for analysis; analyze samples for anions by CE; analyze samples for dissolved cations by ICP-AES; perform qualitative interpretation of water-quality data by graphical methods; and perform quantitative interpretations of water-quality data by computer models. In addition to providing interdisciplinary educational and research opportunities at the undergraduate level, acquisition of a CE enhances the department's ability to develop undergraduate laboratory exercises focusing on water-quality analysis.