Background: The work describes the voltammetric determination of mercury(II), copper(
II), lead(II), cadmium(II), zinc(II) by square wave anodic stripping voltammetry (SWASV) in
Methods: The voltammetric measurements were carried out using a conventional three electrode
cell and two working electrodes, a gold electrode (GE) and a stationary hanging mercury drop electrode
(HMDE). The analytical procedure was 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, precision as repeatability, expressed as relative standard deviation (sr) was of
the order of 4-6 %, while authenticity, expressed as relative error (e) was generally of the order of
5-8 %. Once set up on the standard reference materials, the analytical procedure was applied to
commercial herbal medicine samples, and a critical comparison with spectroscopic measurements
was done to evaluate the analytical performance.
Results and Conclusion: Results are also processed by Principal Components Analysis (PCA),
which provides very easy-to-read graphic outputs evidencing the influence of herbs prewashing on
the content of risky elements. The correlation matrix is also obtained, allowing to study correlation
between elements or methods.