Elemental profile and oxygen isotope ratio (d18O) for verifying the geographical origin of Chinese wines

The elemental profile and oxygen isotope ratio (d18O) of 188 wine samples collected fromthe Changji, Mile, and Changli regions in China were analyzed by inductively coupledplasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectroscopy(ICP-OES) and isotope ratio mass spectrometry (IRMS), respectively. By combiningthe data of d18O and the concentration data of 52 elements, the analysis of variance(ANOVA) technique was firstly applied to obtain the important descriptors for thediscrimination of the three geographical origins. Ca, Al, Mg, B, Fe, K, Rb, Mn, Na, P, Co, Ga,As, Sr, and d18O were identified as the key explanatory factors. In the second step, the keyelements were employed as input variables for the subsequent partial least squaresdiscrimination analysis (PLS-DA) and support vector machine (SVM) analyses. Then, crossvalidation and random data splitting (training set: test set = 70:30, %) were performed toavoid the over-fitting problem. The average correct classification rates of the PLS-DA andSVM models for the training set were both 98%, while for the test set, these values were95%, 97%, respectively. Thus, it was suggested that the combination of oxygen isotope ratio(d18O) and elemental profile with multi-step multivariate analysis is a promising approachfor the verification of the considered three geographical origins of Chinese wines.