As we reported earlier, a boric acid band formed in a column of weak base anion exchange resin Diaion WA21 can be eluted with pure water, resulting in good isotope fractionation. In the present research, we carried out various experiments using this process in order to find the necessary conditions for producing a displacement chromatogram at the end of the boric acid band, where
10B is enriched. Suitable conditions were found to be as follows: the concentration of boric acid was 0.1 mol/
l, the operating temperature was 40°C and the flow rate was 20 m
l/hr·cm
2. Under these conditions, four experimental runs having different migration lengths (1, 2, 4, 8 m) were carried out by a new method which we named “Isotopic Plateau Holding Displacement Chromatography”. In these experiments, the enriched part of band was always preceded by the isotopic plateau part, in which the atomic fraction of
10B was maintained at its original value. The results of these experiments carried out by this method showed that the concentration of
10B at the end of the chromatogram increased with the migration length, and in the case of 8 m migration,
10B was enriched from an original value of 19.84 to 33.26%. The separation factor
S was found to be constant, 1.0097±0.0002, irrespective of migration length.
抄録全体を表示