| 摘要 |
PROBLEM TO BE SOLVED: To quantitatively analyze oxygen in fluoride glass with high sensitivity and high accuracy by a simple and rapid separation operation by performing the chemical separation of fluorine-18 formed by nuclear reaction by using steam distillation together with deficient equivalent precipitation separation. SOLUTION: After fluoride glass and a standard sample containing a known amt. of oxygen are irradiated with protons, the surface layer of fluoride glass is removed over a thickness of severalμm by chemical etching to measure the wt. of etched fluoride glass. This fluoride glass is melted along with a fluorine carrier with sodium hydroxide and the obtained molten matter is dissolved in distilled water and a precipitate is filtered off to prepare a sample soln. Next, fluorine containing fluorine-18 formed by the irradiation with protons is obtained as hydrosilicofluoric acid by using perchloric acid and silicon dioxide and by steam distillation of the sample soln. to be analyzed and hydrosilicofluoric acid is converted into lanthanum fluoride by a lanthanum nitrate aq. soln. and a specific amt. of fluorine-18 is separated by deficient equivalent precipitation. Then, radioactivity of fluorine-17 is compared to quantitatively determine oxygen. |
