NMR analyses and diffusion coefficient determination of minor constituents of olive oil: Combined experimental and theoretical studies

Abstract

Combined experimental and computational studies on biologically important minor constituents of olive oil, i.e., 1-eicosanol, squalene, α-tocopherol, erythrodiol, stigmasterol, β-sitosterol, campesterol, and cycloartenol, have been performed for analyzing their 1H and 13C NMR spectra. The correlation equations for estimating experimental 1H and 13C NMR chemical shifts from the calculated chemical shifts have been derived and tested for the molecules in which dispersion is effective. The presently obtained experimental NMR signals of these molecules were then assigned on the basis of quantum chemical calculations. The discriminative NMR signals of the minor constituents were determined and discussed. 1H diffusion ordered spectroscopy (DOSY) NMR has been employed to discriminate the minor constituents and determine their diffusion coefficients in deuterated chloroform. We calculated some physicochemical parameters of these molecules involving their shapes and sizes as well as their interaction with solvent. Then, we found a regression equation that can be used in estimating diffusion coefficients of other compounds. © 2012 American Chemical Society.