Desenvolvimento de um procedimento de mineralização de mosto para análise elementar por digestão por microondas

Analytical NoteThe present work describes the development and validation of a high pressure microwave-assisted mineralization procedure for the determination of metals in grape must by spectrometric techniques. Metals of special oenological and food safety importance (Al, Co, Cu, Cd, Pb) were used as model elements to achieve the optimum working conditions. The study was conducted by monitoring their concentration in experimental samples by ETAAS. Different combinations of HNO3 and H2O2 were tested and an optimal volume of 1 mL of each reagent, added to 2 mL of sample, was selected for further studies. In comparison with experimental conditions described in literature for the mineralization of grape must and wine by HPMW, the proposed procedure requires very low reagent consumption. Time and temperature were regarded as factors in the optimization study of microwave oven program, resulting in 72 minutes of extension including ventilation. The procedure trueness and precision were evaluated using grape must and wine samples. For each element three different levels of addition were performed. The recovery range was from 94% (Co) to 113% (Pb) in grape must and from 96% (Cu) to 128% (Al) in wine. Relative standard deviations ranged from 1% (Cd) to 11% (Al) in grape must and from 2% (Cd, Pb) to 9% (Co) in wine (n = 10). The proposed procedure is suitable for grape must and wine mineralization with a view to trace element analysis

Effect of wood aging on wine mineral composition and 87Sr/86Sr isotopic ratio

The evolution of mineral composition and wine strontium isotopic ratio 87Sr/86Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87Sr/86Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87Sr/86Sr, not precluding the use of this parameter for wine traceability purposesinfo:eu-repo/semantics/publishedVersio

Contaminant elements in wines: a review

Approximately ten years after a first critical review of the authors on the occurrence of contaminant elements in wine, the subject remains of the utmost importance within the technological, food safety and legal concern. Future developments on toxicological and analytical field, as well as on international trade, will promote changes in existing regulations. Increasing concern with wine food safety may lead to the enlargement of the list of elements to control, and the change of terms in which the acceptable maximum limits are established. This paper, based on the introduction chapter of a Doctoral Thesis, presents a brief approach to the mineral composition of wine, and reviews a large group of contaminant elements (information also systematized in a table), including research results obtained by the authors. Aspects such as origin, levels of occurrence, evolution throughout the technological processes, potential sources of contamination, distribution under different chemical species, toxicity, analytical determination and acceptable maximum limits, vary considerably among contaminant elements

Effect of bentonite characteristics on the elemental composition of wine

Physical, chemical, and mineralogical characteristics of six bentonites were assessed and related to their elemental release to wine. Extraction essays of bentonites in wine at three pH levels were carried out. The multielemental analysis of bentonites and wines was performed by atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Bentonite addition resulted in significantly higher concentrations of Li, Be, Na, Mg, Al, Ca, Sc, V, Mn, Fe, Co, Ni, Ga, Ge, As, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Ba, W, Tl, Bi, and W. In contrast, the concentrations of B, K, Cu, Zn, and Rb significantly decreased. A strong correlation between Na concentrations of treated wines and its content in bentonite exchange complex was observed. Al and Fe contents reflected bentonite extractable aluminous and ferruginous constituents, while Be, Mg, Ca, V, Mn, Ni, Ge, Zr, Nb, Mo, Sn, Sb, Tl, Pb, and U concentrations reflected the elemental composition of bentonites. Several nonconformances with OIV specifications demonstrated the need for an effective control

Determination of zinc in wine by flame atomic absorption spectrometry (FAAS). Validation of the analytical method

O doseamento do zinco (Zn) em vinhos justifica-se pelo seu potencial efeito tóxico sob o organismo humano e ainda por se encontrar na origem de acidentes de estabilidade fisico-quimica, No presente artigo, é apresentada a descrição e caracterização intralaboratorial do método de determinação analítica do etor total de Zn em vinhos por espectrofotometria de absorção atómica com chama. A praticabilidade, especificidade, modelo matemático da curva de calibração, limites analiticos, taxas de recuperação e aplicabilidade, repetibilidade e reprodutibilidade intralaboratorial, são algumas das caracteristicas avaliadas, tendo sido utilizados vinhos brancos, tintos e licorosos para o seu estudo

Release of contaminant elements from bentonites to wine: a contribution to achieve a test solution

The release of mineral elements from six bentonites to wine and to the test solution established by the OIV was evaluated in order to compare the extraction performance of both solutions.Significant differences between wine and tartaric solution results for 34 mineral elements analyzed by AAS, ETAAS and ICP-MS were observed, suggesting that the extraction solution proposed by the OIV is not suitable for bentonite quality control purposes