The improvement of analytical methods makes the search for new technologies fast, accurate and low cost are constantly being reviewed and evaluated. The main objective of this research was to compare three forms of extraction of potassium (nitro-perchloric decomposition, extraction with water and extraction with diluted solution of HCl) of plant tissues samples of Tanzania grass (Panicum maximum cv. Tanzania) and alfalfa (Medicago sativa cv. Crioula). The methods of K extraction of Tanzania grass and alfalfa plant tissue samples in acid solution or diluted with water were equivalent to the traditional method of nitro-perchloric decomposition and can replace it.
nitro-perchloric decomposition; HCl 1 mol L-1; water extraction
