Abstract
The concentration of minerals for two herbal Libyan plants, Marrubium vulgare L and Brassica oleracea L have been determined utilizing four digestion methods to prepare plants samples. These elements include Ca, Mg, K, Na, P, Fe, Mn, Zn, Cu, Co, Cr, Ni, Pb and Cd which are detected by flame atomic absorption spectrometry and flame photometer. Regardless of the digestion methods, Ca, K, Mg, Na, and Fe as macronutrients are found to be in the highest level in these herbals. The concentration of the micronutrient Ni has the highest concentration followed by Zn and Mn. While, Co and Li were found to be at a low concentration. Pb as a toxic element was found in a relatively moderate level. moreover, the microminerals Cr, Co and the toxic element, Cd, were under a detection limit. Statistical (PCA, PLS-DA HCA and Boxplot) results reveal the significant variation between extraction method and other digestion methods. These differences could relate to the ability of water extracting only soluble salts. In the meantime, (HNO3/HClO4) digestion method has the superiority over other digestion methods. The boxplot results also reveal the significant variance according to the mineral composition. For example, these herbals have a significant variance in the levels of Ca, K, Fe, Pb and Ni. While there are small significant differences between these herbals in terms of Zn and K.