Ultrasonic nebulization inductively coupled plasma optical emission spectrometry method for wine analysis

Abstract

A methodology was developed to determine mineral elements in wines using Inductively Coupled Plasma Optical Emission Spectrometry combined with ultrasonic nebulization. The concentration of 36 elements (Al, B, Ba, Bi, Ca, Cd, Ce, Co, Cr, Dy, Er, Eu, Fe, Gd, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Sb, Sc, Sm, Sr, Tb, Ti, Tm, V, Y, Yb, and Zn) was determined in 59 wine samples and used to distinguish between Brazilian and Spanish wines. The best conditions for the plasma were selected using a two-level factorial design: radiofrequency power 1500 W; plasma gas flow rate 15 L min−1; auxiliary 0.70 L min−1; and nebulizer 0.40 L min−1. An exploratory multivariate analysis by Principal Components Analysis (PCA) was employed to distinguish among the analyzed wines. The elements B, Ca, Fe, K, Mg, and Na were the most abundant in all the wine samples analyzed; Al, Li, Na, Sb, Sr, Tb, and Ti were found in highest concentrations in red wines from Spain; Ce, Dy, and Mn prevailed in white wines from the San Francisco River Valley (Brazil). The grouping of the samples of wine in relation to either being red or white wines was verified by PCA: the concentrations of the elements Cd, Fe, K, Mg, Mo, Ti, and V were significantly higher in the red wine samples. Spanish red wine samples presented lower amounts of the elements Ca, Dy, La, Mn, Nd, Pr, and Tm and greater concentrations of the elements Al, Na, Sb, Sr, and Tb in relation to the Brazilian ones, tending to group them thusly. Brazilian red wine samples presented greater variability in their mineral profile, compared to the Spanish ones.