Traditional courses in analytical chemistry typically devote a significant amount of time to the study of both electrochemical methods and analytical separations. While most students have little difficulty understanding and applying the basic principles of separation techniques, the fundamentals of electrochemistry tend to remain much more abstract. Unfortunately, most traditional electrochemistry laboratory exercises do little to make the subject come alive for the student. The laboratory project outlined in this proposal is designed to provide students with a dynamic interactive platform for instruction in electrochemistry and chromatography by focusing on the development of an electrochemical detection scheme for liquid chromatography (LC-EC). A four-week laboratory sequence emphasizing the development of an LC-EC method for carbohydrate determinations will be designed for our senior-level instrumental analysis course. (A one-week exercise based on applications of this method for quality control will be incorporated into our sophomore-level introductory analytical course.) At the heart of this project is a LabVIEW-based data acquisition interface. Each electrochemical experiment will be controlled by a LabVIEW program, commonly referred to as a virtual instrument, which gives students complete control of all electrode potential and timing parameters. After an initial focus on the fundamentals of cyclic voltammetry, the voltammetric behavior of glucose will be applied to the development of a detection scheme for carbohydrates in a flow-through system. Students will be led to discover that a pulsed potential sequence is needed in order to obtain a reproducible response. A multi-step potential waveform (E vs. t) will be developed to include both formation and dissolution of a surface oxide layer, allowing the student to visualize electrochemical processes at the molecular level. This waveform will then be applied to the quantitative determination of carbohydrates separated by anion-exchange li quid chromatography.
