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

获得毛细管电泳（CE）系统，可以分析天然水样中溶解的无机和有机阴离子。常规分析溶解阴离子以评估水质，并辅以电感耦合等离子体原子发射光谱（ICP-AES）方法分析溶解阳离子。这些数据是理解地球化学过程（包括水岩相互作用、污染物迁移和碳循环）背景下的天然水成分的基础。分析水中溶解的阴离子通常用离子交换色谱法来完成。然而，最近将CE方法应用于水样显示出许多优于离子交换方法的优点，特别是在学术环境中。CE系统具有更少的移动部件，更便宜的色谱柱，更小的溶剂浪费量和更快的分析。在《地球化学导论》课程中，高年级地质学专业的本科生将学习水地球化学的概念（例如，平衡、活度和浓度关系，以及矿物溶解度）。这些概念可以应用于了解控制自然（和可能受污染的）地表水样品的过程。学生们将完成一个由六部分组成的练习，其中他们将执行以下任务：在野外收集水样；准备水样进行分析；用CE分析样品中的阴离子；ICP-AES法分析样品中溶解的阳离子；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。除了为本科生提供跨学科的教育和研究机会外，获得环境行政证书还可以提高本系开发本科生水质分析实验室练习的能力。

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.