Voltammetric determination of metals as food contaminants: an excellent alternative to spectroscopic measurements. application to meals, vegetables, mussels, clams and fishes

The work regards the voltammetric determination of trace metals in different kinds of food matrices. First goal is relevant to the correct analytical procedure for the voltammetric determination of trace and ultra-trace metals - Platinum Group Metals (PGMs), Mercury (II), Copper (II), Lead (II), Cadmium (II) and Zinc (II) - in meals, vegetables, mussels, clams and fishes: this allows, evidently, to check high quality foodstuffs. The second goal is to show the advantages that the electrochemical approach may offer over atomic absorption spectroscopy. First, voltammetry, together with the standard addition method, is a valid analytical technique (good selectivity and, especially sensitivity) for the simultaneous element determination in complex matrices and it does not require enrichment steps, like solvent extraction, and/or particular sample treatments. Second, as regards precision, accuracy and limits of detection, the results obtained with the two techniques are both good and comparable in all cases, although voltammetry is better than atomic absorption spectroscopy, allowing simultaneous metal determinations in most cases. In fact, also Inductively Coupled Plasma (ICP) and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) permit multi-element determination, but the great advantage in using voltammetry is certainly the equipment-related costs: very low in the case of voltammetry, extremely high in the case of ICP and ICP-MS, in the latter case as much as 25-30 times higher. In this work Electrothermal Atomic Absorption Spectroscopy (ETAAS) was also chosen as comparison technique because of its well-established and tested robustness.