Identification of similarities in metallic content of herbal infusions using non-linear approach.

The content of Cd, Cr, Cu, Fe, Pb, Mn, Ni and Zn was determined, using flame atomic absorption spectrometry in infusions made from commercial herbal mixtures readily available in herbal stores. ANOVA test revealed that the metal contents did not differ considerably in most of infusions. The scatter plot of principal component analysis (PCA) designated infusions characterized by similar contents of trace elements. It was possible to indicate distinctive metal concentrations in Pyrosan, Septosan and Urosan infusions as they vastly contrasted with others. The levels of Mn, Zn, Cd were characteristic for Pyrosan infusions, while Cr, Fe, Cd were specific to Septosan, and Mn, Zn, Fe to Urosan. Self-organizing maps did not fully correspond with PCA results because PCA classified samples relying mainly on apparent similarities in metal contents.