At Arizona Western College (AWC) chemistry students do not wait until Organic Chemistry to use gas-liquid chromatography (GLC) instrumentation. Rather, over several weeks General Chemistry 2 students carry out a series of simple GLC mini-labs that allow students to determine via experimentation how molecular weight, boiling point, and oven temperature influence retention time in a chromatographic separation. These mini-labs then serve as a foundation for a more detailed analysis of street-grade gasoline and commercially available fuel and fuel injector system products.
Each GLC mini-lab is prefaced with a pre-lab activity, comprised of two or more conceptual-type questions, that asks students, among other possibilities, to predict or speculate about the relationship between the factor being examined on the GLC instrument that week and its influence on retention time. GLC questions embedded in quizzes and exams (i.e. post-lab) and related to the lab activities are used to asses student understanding of GLC, a kind of "before vs. after" assessment tool.
Specifically, the presenter will discuss the mini-labs, student answers to the pre- and post-lab questions, and student responses to how the use of high-end instrumentation contributed to their learning chemistry.
The author gratefully acknowledges the financial support of the National Science Foundation (DUE-0310264) to purchase a high-end gas-liquid chromatograph.
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Back to The 33rd Northeast Regional Meeting (July 14-17, 2005)