An analytical procedure regarding the voltammetric determination of mercury(II), copper(II), lead(II), cadmium(II) and zinc(II) by square wave anodic stripping voltammetry (SWASV) in matrices involved in food chain is proposed. In particular, tea leaves were analyzed as real samples. The digestion of each matrix was carried out using a concentrated HClโHNO3โH2SO4 acidic attack mixture; 0.01molLโ1 EDTA-Na2
+0.15molLโ1 NaCl+0.5molLโ1 HCl was employed as the supporting electrolyte. The voltammetric measurements were carried out using a conventional three electrode cell, employing, as working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode (HMDE). The analytical procedure has been verified on the standard reference materials Spinach Leaves NIST-SRM 1570a, Tomato Leaves NIST-SRM 1573a and Apple Leaves NIST-SRM 1515. For all the elements, the precision as repeatability, expressed as relative standard deviation (sr
) was of the order of 3โ5%, while the trueness, expressed as relative error (e) was of the order of 3โ7%. Once set up on the standard reference materials, the analytical procedure was applied to commercial tea leaves samples.
A critical comparison with spectroscopic measurements is also discussed.