The wine samples were obtained from eight different regions of Brazil. All samples were produced specially for this work, using C. sauvignon grapes, harvested in 2009. This provides more relevance to this study, since there is a guarantee regarding the origin of the samples. This, however, cannot be assured when evaluating samples of commercial wines. A total of 32 wine samples from eight regions of the south and the northeast of Brazil, as specified in Table 3, were evaluated. The location of the seven wine-growing areas in the south of Brazil is shown in Fig. 1; it should be noted that the distance between area 1 and area 7 is more than 1000 km. The eighth location is in the northeast of Brazil, more than 3000 km from Rio Grande do Sul, and is not shown in Fig. 1. All wine samples were stored in a refrigerator to preserve their properties. For direct analysis, 10 mL of wine were transferred to 15-mL volumetric flasks; appropriate volumes of HCl and Cs solutions were added to result in a final concentration of 1% (v/v) each of HCl and Cs, and the volume was completed with ultrapure water. All samples were prepared in triplicate.