Compositional Analysis of Mixtures of Oleate Esters of Short Chain Alcohols (C1-C4) by Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (qPNMR)

Ronald P. D’Amelia^1, , Brandon Khanyan¹ and Joseph Mancuso¹

¹Chemistry Department, Hofstra University, Hempstead, NY

Cite this paper:
Ronald P. D’Amelia, Brandon Khanyan and Joseph Mancuso. Compositional Analysis of Mixtures of Oleate Esters of Short Chain Alcohols (C1-C4) by Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (qPNMR). World Journal of Chemical Education. 2022; 10(1):1-7. doi: 10.12691/wjce-10-1-1

Abstract

Quantitative nuclear magnetic resonance spectroscopy (qNMR) is a technique used to determine the concentration of one or more analyte within a mixture. Although NMR spectroscopy is typically used to qualitatively determine molecular structure, the quantitative application of NMR extends to concentration determinations and purity assessments. Described herein is an experiment designed to increase awareness of both the qualitative and quantitative applications of NMR spectroscopy that could be integrated into undergraduate analytical and instrumental chemistry laboratory course curriculums. The experiment entails the quantitative analysis of binary long-chain monounsaturated fatty acid mixtures ranging from 0% to 100% in 20% intervals of methyl oleate (MeOl), ethyl oleate (EtOl), propyl oleate (PrOl) and butyl oleate (BuOl) using proton NMR. The goal of the experiment is to determine the structure and weight percent composition of both analytes in each of the mixtures. The results show a strong, linear correlation between the gravimetric compositions and the weight percent compositions found using proton NMR. The experiment supports qNMR as a tool for determining weight percent compositions of mixtures and can be incorporated at the undergraduate chemistry laboratory level.

Keywords:
quantitative analysis Nuclear Magnetic Resonance undergraduate laboratory experiment hands-on learning oleate esters oleate ester mixtures

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