ANALYTICAL METHOD FOR STRONG ACID AND HYDROFLUORIC ACID IN SOLUTION CONTAINING COMPLEX FLUORIDE ION

摘要

PURPOSE:To obtain more accurate value of analysis of a free acid, by correcting the dialysis coefficient of the free acid diffusing through an anion exchange membrane by the concentration of a metallic ion. CONSTITUTION:A nitric acid-hydrofluoric acid standard solution B is introduced into a thermostat 2 and diffusion dialysis is carried out in a dialysis bath 3 and then, the solution B is introduced into a measuring apparatus 4. Further, a buffer solution C is added and the solution B is introduced into an acid concentration measuring apparatus 5 and then, electrode potential is inputted into a computer 7. Another standard solution having a different concentration is treated in the same way and K in the formula is calculated by the electrode potential at this time, where Ci is acid concentration of the sample solution, Cs is acid concentration of the standard solution, Vi is electrode potential of the sample solution, Vs is electrode potential of the standard solution. Next, the sample solution A is introduced into the thermostat 2 from a filter 1 and the electrode potential of acid is stored in the computer 7 in the same way. On the one hand, the solution A passed through the filter 1 is introduced into a metallic ion concentration measuring apparatus 6 and the metallic ion concentration is put in the computer 7. A correction coefficient A is read from the curve of memoriezed correction coefficient vs metallic ion concentration and the acid concentration of the sample solution is found by computing the formula.