removed by heating the lixiviated solution at a temperature below the boiling point after ph adjustment the solution is passed through a cation exchange column inorganic salts and alkaline amino acids are removed and then the tetrodotoxin is adsorbed and eluted from activated carbon the tetrodotoxin is crystallized by adjusting the ph to 8 10 application_number US 69571100 A description the following general procedures should be followed to extract tetrodotoxin from animal tissues with high yield tissues of puffer fish preferably the ovaries are a preferred source of tetrodotoxin grind the tissue into pieces less than 1 cubic cm put into a container and add de ionized water in an amount equal to 1 5 times by weight of the tissue then add acetic acid weighing 0 05 u02dc 1 preferably 0 1 0 3 by weight of the tissue to extract ttx from the tissue more efficiently stir for a few hours at room temperature filter the liquid using nylon filtering material with a pore size of 100 200 meshes per square inch and stainless steel mesh of 40 60 meshes per square inch collect the filtrate heat quickly to 70 95 u00b0 c for about 3 25 minutes cool down and filter out the scleroprotein that has been separated out so a yellow transparent liquid is obtained and called first lixiviated clear liquid inject intraperitoneally 0 4 ml of the first clear lixiviated liquid into a mouse having a body weight of 20 grams the tissue will be determined to be extremely toxic raw material if the mouse dies within 50 seconds or highly toxic raw material if between 50 u02dc 70 seconds or mildly toxic raw material if between 70 u02dc 90 seconds the lixiviated liquid that causes such a mouse to die after more than.