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ERIC Number: EJ1163633
Record Type: Journal
Publication Date: 2017-Dec
Pages: 5
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0021-9584
EISSN: N/A
qHNMR Analysis of Purity of Common Organic Solvents--An Undergraduate Quantitative Analysis Laboratory Experiment
Bell, Peter T.; Whaley, W. Lance; Tochterman, Alyssa D.; Mueller, Karl S.; Schultz, Linda D.
Journal of Chemical Education, v94 n12 p1969-1973 Dec 2017
NMR spectroscopy is currently a premier technique for structural elucidation of organic molecules. Quantitative NMR (qNMR) methodology has developed more slowly but is now widely accepted, especially in the areas of natural product and medicinal chemistry. However, many undergraduate students are not routinely exposed to this important concept. This article describes a simple and practical lab experiment that has been successfully performed by students in a Quantitative Analysis class for several years and is based on a comparison of relative integration areas of species present in spectra of compound mixtures. In this experiment, [superscript 1]H NMR spectroscopy is used to determine the purity of common organic solvents using dimethyl sulfoxide as an internal standard in D[subscript 2]O. Groups of students analyze unknown samples containing one of the following solvents: methanol, ethanol, 2-propanol, tetrahydrofuran, or acetone, to which water has been added as an impurity. Over a period of five years, 54 students analyzed samples ranging from 60% to 99% purity with an average error of 2.64%. This experiment fills a niche in the initial portion of a standard Quantitative Analysis lab sequence by differentiating between qualitative and quantitative analysis, providing exposure to equipment not usually encountered in an introductory analytical lab, and generating numerical data for students to analyze and evaluate.
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Identifiers - Location: Texas
Grant or Contract Numbers: N/A