VOLTAMMETRY AND ATOMIC ABSORPTION SPECTROSCOPY: A CRITICAL COMPARISON OF TWO TECHNIQUES FOR TOXIC METAL DETERMINATION IN SEAFOOD AND FOOD SUPPLEMENTS

A quick diffusion of heavy metals and potentially toxic metals as environmental contaminants has aroused the interest in their determination. Indeed, toxic metals, together with pesticides, are very dangerous pollutants owing to their bioaccumulation and toxicity. It is therefore necessary to determine these metals at trace and ultra-trace level, and particular attention is due in the case of food analysis. Among all matrices, sea food is particularly important, as it is perhaps the one mainly affected by contamination from toxic metals. Indeed, toxic metals accumulate in certain marine species and thus enter the aquatic food chain. In particular mussels, clams, oysters, but also fishes sequestrate and concentrate several metals from their aqueous environment, possibly becoming dangerous to human health in consequence of their consumption. In particular, mussels, clams and oysters are filtering organisms, and then they call particular attention and require inspections before being sold on the market. Other food matrices particularly influenced by pollution from toxic metals are also the food supplements, e.g., wine and tea. These beverages may be rich in toxic metals, as a result of pesticides and fertilisers employed in agricultural treatments prior to the harvest of raw materials. In any case, the metal determination in food matrices evidently must be accurate, reproducible and especially it must show very low limits of detection. The present work reports and discusses the different analytical methodologies for the voltammetric and spectroscopic determination of some potentially toxic elements (copper, zinc, cadmium, mercury, tin, lead and antimony) in mussels, clams, oysters, fishes, wine and tea. This work focuses also on the critical comparison between voltammetric and spectroscopic instrumental techniques.