AVALIAÇÃO DA LABILIDADE DO ALUMÍNIO EM INFUSÕES DE ERVA-MATE (Ilexparaguariensis St. Hil.) EMPREGANDO VOLTAMETRIA ADSORTIVA DE REDISSOLUÇÃO CATÓDICA

Abstract

Yerba mate is a plant widely consumed as hot and cold infusions, known as mate and tererê, respectively. Studies show that although mate presents several beneficial properties for human health, it may contain high levels of aluminium. Aluminium is anelemental that doesn`t have known biological functions and can be associated with behavioral and neurological diseases. Speciation studies allow to estimate the bioavailability of this element and hence to its toxicity. In this study, an analytical protocol for the speciation of aluminium in infusion employing adsortivecathodic stripping voltammetry (AdsCSV) using alizarin red S (DASA) as ligand agent was developed. In this procedure, the total dissolved monomeric aluminium in infusions was determined by AdsCSV through on the formation of a complex with DASA at pH 8.0. DASA was able to sequester the Al organically bound by phenolic compounds and organic acids. At pH 5.0, the complexes were formed between DASA and labile Al fractions.Therefore, theconcentrationsofaluminiumcomplexed with organic ligands in infusions wascalculated by the difference between the concentrations of total dissolved aluminum and labile dissolved aluminium. The parameters operational employed in speciation analysis we optimized. The method optimized was validated bytests of linearity, sensitivity, precision, accuracy and interference. The proposed analytical procedure was adequate for speciation analysis of Al in infusions of yerba mate, showing high sensitivity and low cost. It was possible to verify that,aluminium in infusions of commercial yerba mate and in samples from different stages of the industrial process is mostly complexed to natural organic compounds from the plant. However the Al-Labile in some samples of infusion exceeds the recommended weekly intake of world health organization (WHO) in samples of mate and mate tea. The dissolved organic compounds in infusions were determined qualitative and quantitatively by molecular absorption spectrophotometry. A possible correlation between the lability of aluminiumand organic compounds in infusions of yerba mate was evaluated through statistical tools. In general, it was observed the lability of aluminium depends on the concentrations of melanoidins in infusions.