Investigation of liquid three-phase systems by means of radioactive indicators

The concentration of lanthanide (LaCl3, TbCl3) trace amounts in liquid three-phase systems with the use of diantipyrylmethane as an extraction reagent is studied. The required concentrations of reagents; acids; organic and aqueous phase correlations are found. While using chloroform mixtures with benzene or heptane in the presence of potassium iodide the method permits to extract up to 1x10-9 g of lanthanide from the volume of 100 ml into the third phase which volume is less than 1 ml. The method developed is used to determine 160Tb in wastes