medicinal herbs; essential and toxic metals; LIBS; ICP OES; chemometrics;INDUCED BREAKDOWN SPECTROSCOPY; PRINCIPAL COMPONENT ANALYSIS; TRACE-ELEMENTS; NEUTRON-ACTIVATION; INFUSIONS; INFORMATION; FINGERPRINT; CALCIUM; PLANTS; HONEY
Essential and toxic metals were determined in eighteen samples of medicinal herbs from Poland, Lithuania and Serbia by means of laser-induced breakdownspectroscopy (LIBS) and inductively coupled plasma optical emission spectrometry (ICP OES). Calcium, K and Mg concentrations were obtained in % (m/m) and other metals (Na, Co, Cu, Fe, Mn, Ni, Zn, Cd, Cr and Pb) in mg kg-1. The fact that the herb samples analyzed belonged to specific plant species and represented different morphological plant parts explained the characteristic distribution in two-dimensional scores plots obtained by principal component analysis (PCA). A strong correlation of LIBS results was achieved in comparison to those obtained by ICP OES for Ca, K and Mg. Differences in the types of infusions were observed, in that leaves are related to Zn and Ni concentrations, leaves and flowers to Co, Ca and Mn concentrations and flowers to K, Na, Mg and Fe content.