DIRECT ANALYSIS OF PLANT MINERALS AND COMPARISON OF EXTRACTION PROCESSES USING ICP-AES

The mineral contents of two plants, Chrysanthemum indicum flowers and Rhoeo spathacea leaves, were analysed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). This technique allows metallic and non-metallic minerals, like phosphorus and sulphur, to be analysed directly. The calcium concentration was found to be high in both plants, compared to other local vegetables and plants. In R. spathacea, the calcium level in the leaves is not affected by the level of calcium in the soil in which they are grown. Four different methods of extracting calcium from three different plants, (Clitorea ternatea, R. spathacea and C indicum) were examined, and the best method is by using a pressure cooker followed by direct boiling and possibly, double boiling and crockpot. There is no significant difference between the crockpot and double-boiling system. Using the same method of extraction, the percentage of extraction is dependent upon the type of plant. The high calcium concentration in these plants shows that they can be significant sources of calcium when brewed as herbal drinks for human consumption.