Chemical Education Today edited by
NSF Highlights
Susan H. Hixson
Projects Supported by the NSF Division of Undergraduate Education
The Influence of Modern Instrumentation on the Analytical and General Chemistry Curriculum at Bates College
National Science Foundation Arlington, VA 22230
Richard F. Jones Sinclair Community College Dayton, OH 45402-1460
by Thomas J. Wenzel
Prior to the introduction of instructional equipment grant programs at the National Science Foundation, the prospect of having instruments such as a gas chromatograph– mass spectrometer (GC–MS) or inductively coupled plasma– atomic emission spectrophotometer (ICP–AES) at Bates College seemed remote. Beginning with a College Science Instrumentation Program (CSIP) grant in 1985, and through subsequent Instrumentation and Laboratory Improvement (ILI) and Course, Curriculum, and Laboratory Improvement (CCLI) grants, these instruments as well as a gradient high-performance liquid chromatograph (HPLC), ion chromatograph (IC), and capillary electrophoresis system (CE) have been acquired. The experiments described in the earlier proposals were relatively brief and designed to introduce students to the basic operation, theory, and application of the equipment. Coupled with modern instrumentation received through research grants (300-MHz nuclear magnetic resonance spectrometer, capillary GC with flame ionization detector, fluorescence spectrophotometer with time resolution capabilities), the educational value of the relatively mundane experiments that the students performed and the superficial understanding they obtained about a suite of instruments was brought into question. The experiments were not an accurate representation of how scientists use equipment. The instru-ments were not used to facilitate investigations, solve problems, or measure trace constituents of complex samples that required a realistic workup prior to analysis. Beginning in 1991, the two analytical courses offered at Bates were completely revised. These revisions involved altering the topics in the two courses, changing the classroom from a lecture to cooperative learning format, and having students conduct small-group, semester-long projects in the lab (1, 2). Examples of projects have included the analysis of polycyclic aromatic hydrocarbons in wood smoke, creosote, diesel exhaust, and charbroiled meats (GC–MS or HPLC with fluorescence detection); volatile organic compounds in air (GC–MS); trihalomethanes in drinking water (GC–MS); heavy metals in wastewater sludges (ICP–AES); nitrate, nitrite, and sulfate in food products (IC); amino acid content of vegetables (HPLC with fluorescence detection); caffeine, theophylline, and theobromine in chocolate (HPLC with ultraviolet detection); and DNA restriction fragment analysis (CE). The use of projects has had many positive outcomes. Advanced features of the equipment are used and the investigative and problem-solving nature of analytical chemistry is demonstrated. Students gain a better appreciation of 1164
what it means to undertake a chemical analysis, and realize how difficult it is to get a reliable answer when analyzing trace substances. The projects generate a level of independence, critical thought, and empowerment that was not observed in the previous format. Students enjoy the projects and commit more time to the lab. Fundamental laboratory skills and techniques are necessary to complete the projects. Even though students use one instrument, they understand it in great detail and, having mastered the operation of one sophisticated piece of equipment, are not timid about approaching another when required for course work or research. The changes in the upper-level courses were so satisfying that such an approach was warranted at the introductory level as well. Most students in the introductory course at Bates do not major in chemistry, but are in allied fields such as biology, geology, environmental studies, and physics. They formulate crucial impressions of chemistry through their introductory course experience, and will often use chemistry or interact with chemists in their careers. Beginning in 1998, a new thematic sequence that connects basic chemical concepts to the study of the environment was first offered (3). The course counts for the chemistry major and fulfills the general chemistry prerequisite for all upper-level chemistry courses. In addition to introducing the fundamentals of chemistry, the course is designed to show the broader societal impact of chemistry. In the first semester, students undertake a semester-long project. This past year they examined whether plants grown in soil contaminated with lead paint dust take up more lead than those grown in uncontaminated soil, and whether lead uptake varies with the acidity of the watering solutions. Lead in the plant and soil samples was analyzed using ICP–AES. Once the project was underway, students were able to collect rain and analyze it for the content of nitric and sulfuric acid using an ion chromatograph obtained through a CCLI grant. The analyses verified that the watering solutions selected by the students were representative of acid rain in our area. A GC–MS obtained through the same CCLI grant was used to analyze the volatile organic compounds in pine needles and auto exhaust. Students then collected air samples on a road and in a pine grove near campus to examine the relative contributions from each source. Not surprisingly, higher levels of terpenes were found in air samples in the pine grove than by the road. The opposite trend was observed for methyl benzenes. In the second semester, students monitor and maintain the water chemistry of a marine aquarium (4). Inorganic anions are some of
Journal of Chemical Education • Vol. 78 No. 9 September 2001 • JChemEd.chem.wisc.edu
Chemical Education Today
the species that are measured, and the results obtained using classical and ion chromatographic methods are compared. The positive outcomes observed in the upper-level courses have occurred with the new format of the introductory lab as well. Other members of the Chemistry Department at Bates are now considering the development of a section of general chemistry with a life science theme. The beneficial changes in these courses would not have happened without the availability of modern equipment made possible through grants from the National Science Foundation. Acknowledgments I thank Bates College for its repeated willingness to provide matching support for instructional and research equipment grants. The support of the National Science Foun-
dation, especially the Division of Undergraduate Education, is greatly appreciated (Capillary GC: RII-8217989; Gradient HPLC: CSI-8551126; Spectrofluorometer: DMB8514895; GC–MS: CSI-8750027; 300 MHz NMR: CHE8921335; ICP–AES: DUE-9452296; CE: DUE-9850730; GC–MS and IC: DUE-9950314). Literature Cited 1. 2. 3. 4.
Wenzel, T. J. Anal. Chem. 1995, 67, 470A–475A. Wenzel, T. J. Anal. Chem. 1998, 70, 790A–795A. Wenzel, T. J.; Austin, R. N. Environ. Sci. Technol., in press. Hughes, K. D. Anal. Chem. 1993, 65, 883A–889A.
Thomas J. Wenzel, Department of Chemistry, Bates College, Lewiston, ME 04240;
[email protected].
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