Wine analysis by 1D and 2D NMR spectroscopy

We have measured 1D and 2D $^1$H and $^{13}$C NMR spectra of selected Slovenian wines. Partial assignment of $^1$H and $^{13}$C resonances of alanine, valine, leucine, isoleucine, proline, threonine, ethanol, glycerol, butyleneglycol, and of acetic, tartaric, lactic, succinic, and malic acids in the wine samples was carried out by the combination of homo- and heteronuclear experiments COSY, HSQC and HMBC with known spectra of individual compounds. The spectra of wines of different variety, vintage and geographical areas differ mainly in the intensity of particular signals but also in the appearance of some signals which offers the possibility to follow the variability in their chemical composition on the ground of $^1$H and $^{13}$C signals

Detection of Honey Adulteration by Sugar Syrups Using One-dimensional and two-dimensional High-resolution Nuclear Magnetic Resonance

The importance of honey adulteration detection has recently increased owing to the limited production levels in recent years and to the relative high price of honey, therefore this illegal practice has becoming more and more attractive to producers. Hence the need has arisen for more effective analitical methods aiming at detecting honey adulteration. The present research presents an effective method to detect adulteration in honey falsified by intentional addition of different concentrations of commercial sugar syrups, using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) coupled with multivariate statistical analysis. Sixty-three authentic and 63 adulterated honey samples were analysed. To prepare adulterated honeys, 7 different sugar syrups normally used for nutrition of bees were used. The best discriminant model was obtained by 1D spectra and the leave-one out cross-validation showed a predictive capacity of 95.2 %. Also 2D NMR have furnished acceptable results (cross-validation correct classification 90.5%), although the 1H-NMR sequence is preferable because it is the simplest and fastest NMR technique