Determination of some heavy metals and selenium in Sicilian and Calabrian citrus essential oils using derivative stripping chronopotentiometry

This paper aims to bring some novelty about the concentration of some heavy metals and selenium in biological citrus essential oils (CEO) produced in Sicily and Calabria in different crop years. Derivative stripping chronopotentiometry has been used as an accurate, sensitive, and rapid technique for the determination of Cd, Cu, Mn, Ni, Pb, Zn, and Se in hydrochloric acid extracts of CEO; in the optimized electrochemical conditions, detection limits of <1 μg kg-1 were obtained for all of the studied metals. In particular, the concentrations of metals were determined in biological bergamot essential oils produced in Calabria in 1999 and 2000 and in biological CEO produced in Sicily in 2003 and 2004. The obtained results provided evidence that Mn was the most abundant metal in all of the studied CEO followed by Zn, Ni, Cu, Pb, and Se; Cd concentrations were always lower than the limit of detection (0.6 μg kg-1).