A First Laboratory Utilizing NMR for Undergraduate Education: Characterization of Edible Fats and Oils by Quantitative C-13 NMR

作者：Fry Charles G^*; Hofstetter Heike; Bowman Matthew D

来源：Journal of Chemical Education, 2017, 94(9): 1319-1323.

DOI：10.1021/acs4cherned_71300057

• First-Year Undergraduate/General
• Second-Year Undergraduate
• Analytical Chemistry
• Organic Chemistry
• Inquiry-Based/Discovery Learning
• Consumer Chemistry
• Fatty Acids
• Instrumental Methods
• NMR Spectroscopy
• Quantitative Analysis

Quantitative C-13 NMR provides a straightforward method of analyzing edible oils in undergraduate chemistry laboratories. C-13 spectra are relatively easy to understand, and are much simpler to analyze and workup than corresponding H-1 spectra. Average chain length, degree of saturation, and average polyunsaturated fatty acid content of common edible oils are obtained directly using integrals of the proper regions in the C-13 ID spectra. These spectra segue to 2D H-1-C-13 HSQC experiments that provide an excellent path for students to verify assignments, in particular those associated with polyunsaturated fatty acids. Data acquisition and analysis can be completed in one to two lab sections, although spectrometer scheduling may be necessary for groups of students greater than six. C-13 relaxation measurements of common oils are presented that enable accurate quantitative '3C data to be obtained in reasonable amounts of time (30-40 min per sample) on modern 400 MHz NMR spectrometers.

• 出版日期2017-9