Quantitative analysis of the main components of the wines by means of carbon-13 NMR : optimisation of the method

Abstract

Despite both the low sensitivity and abundance of the carbon 13 nuclei, ¹³C NMR spectroscopy was shown to be an excellent quantitative analytic method for the main components of the wines. The acquisition parameters of the ¹³C NMR spectra optimised by means of the simplexe method lead to excellent linear correlations (r² > 0,999) between the integral of the resonance signals and the concentrations of the corresponding components. Using such optimised parameters, an enhancement of the accuracy was observed. In this way, the technique allows the quantitative analysis of at least 9 components (such as glycerol, tartaric, malic, lactic, succinic, citric acids, butanediols, glucose and fructose) in a sole experiment in approximately one hour with a precision of about 5 %. Typically, concentrations of each component up ta 5.10^-3 M can be measured in very good conditions.