-14-
analyzed in the gamma spectrometer described above. — The specific
radioisotopes could be identified in a sample when the radioactivity of
the isotope was one per cent or more
sample.
of the
total
radioactivity of the
The fractions which contained more than one radioisotope
were further separated by other ion-exchange methods.
Anion fractions
The anion fractions of plankton samples P-6, P-13 and P-15 + P-17
were dried, redissolved in 0.1 M oxalic acid, and passed through 0. 13
cm? x 26-cm columns containing Dowex-1* (200-400 mesh) for the
separation of the anions of 5b, Sn,
Te, and Ru.
The separation was
done by the modified procedure of Smith and Reynolds as described by
Palumbo and Lowman.
The anion fractions of samples P-25 + P-26, P-24+P-35,
and
P-13 + P-15, and the fractions from the secondary separation of P-15 +
P-17, were dried and redissolved in concentrated HCl to separate
complex radionuclide mixtures, as described by Wish.
the
In these ex-
periments the samples were passed through 0.03 em2 x 15 cm-columns
containing Dowex- 1 (200-400 mesh) and the radionuclides were sequentially removed by using mixtures of hydrofluoric and hydrochloric
acids.
Because of the corrosive nature of the HF acid, column plugs
made of lucite shavings were used and the fractions
were collected
*Available from Dow Chemical Co., Midland, Michigan,
in