Platinum and rhodium in potato samples by using voltammetric techniques

Potato is a starchy, tuberous crop from the perennial Solanum tuberosum having high nutritional values. This paper is the first analytical approach to quantify Pt and Rh in vegetal food. In this study a total of 38 different potato samples produced in Europe and one in Australia were investigated. Determinations of Pt and Rh in potato samples were carried out by Differential pulse voltammetry (DPV/a) for platinum and by Adsorptive stripping voltammetry (AdSV) for Rh using standard addition procedure. Because no certified reference potatoes containing platinum and rhodium are available, we used addition standard method. The quantification limits for Pt and Rh are 0.007 and 0.0008 µg kg -1 respectively. Considering all the potato samples, concentrations of Pt and Rh vary in the ranges from 0.007 to 109 µg kg -1 (sample no, 6 potatoes grown in Sicily) and from 0.0008 to 0.030 µg kg -1 (sample no. 3 of potatoes grown in Emilia Romagna), respectively. For both metals, in many cases the concentrations fall near the quantification limit. In all the samples, platinum is always more abundant than rhodium and their mean ratio is 14,500, which is much greater than that of the Earth's crust (about 100).