Analysis of Contaminants in Beverages

Abstract

The main purpose of our researches, in the last years, was to develop reliable methods for the determination of emerging and old contaminants (Pt, Rh, V, Mo, polycyclic aromatic hydrocarbons (PAHs), etc.), at trace levels, in the solutions obtained from the mineralization or extraction of environmental and food matrices, because, in particular for metals, some of them cannot be readily analyzed using traditional method, for example, inductively coupled plasma-optical emission spectrometry and inductively coupled plasma with mass spectrometry techniques. Few data are available on the evaluations of Pt, Rh, V, and Mo concentrations, in food matrices, because have ever been carried out since the use of platinum-group elements in catalytic converters. Among the main food matrices that we have studied, in this chapter, we will discuss two important drinks: wine and coffee. About organic contaminants, PAHs are ubiquitous environmental contaminants, also traces of PAHs have been detected in many foods, including vegetable oils grilled and roasted meat, smoked fish, tea, and coffee. The PAHs in coffee samples have also been reported and their presence is attributed to either contamination of the initial green beans or formation of these compounds during the roasting step. Our results demonstrate that the voltammetric analysis of V, Mo, Pt, and Rh in alcoholic beverages is an excellent method for the determination of traces of these elements even in the presence of several species at higher concentrations. Finally, the above system offers a practical potential for the determination of these elements without any interference due to other species present in the matrix with similar reduction potential. The represented method includes advantages of high sensitivity, high selectivity, simplicity, speed, and low costs. Data here reported constitute the results of the first monitoring campaign of vanadium and molybdenum, platinum, and rhodium concentration levels in alcoholic beverage samples. In conclusion, wine samples analyzed contain levels of V, Mo, Pt, and Rh, under the recommended levels by international organisms for other food, if the quantities consumed daily are not excessive. The method proposed by us for the quantification of PAHs in coffee brews is based on the saponification of matrices and liquid-liquid extraction; the determination is carried out by gas chromatography with mass spectrometry as detector. From the calculated isomeric ratios, we affirm that the PAHs in most of the coffee samples originate from high-temperature processes. Again, from the results of the analyzed samples, we can conclude that moderate coffee consumption does not pose any danger to the toxicological point of view if the quantities consumed are not excessive.