42
(1953) in which negatively charged complexes of divalent Ni,
Mn, Co, Cu,
Fe,
and Zn were adsorbed onto an anion-exchange
regin and selectively eluted with progressively decreasing
milarities of HCl
(Fig.
3).
To convert the mineral components to chlorides,
was taken up in an excess of concentrated HCl,
the ash
heated just to
dryness on a warm (< 200° ¢) hotplate and the process repeated.
If the ash did not dissolve to a clear solution in HCl,
70
per cent HNO3 was added dropwise and the mixture heated until
solution was effected.
The mixture was then evaporated just
to dryness and concentrated HCl added.
This process was
repeated until nitrous fumes were no longer evident during
evaporation.
The dried chlorides from each sample were then
dissolved in 2M HCl and made up to 10 ml volume.
Individual samples,
dissolved in 10 ml volumes of 2M HCl
were added to separate ion~exchange columns constructed as
follows:
(1) A strongly basic,
anion exchange resin,
trimethyl benzyl ammonium-type
Dowex 1X8, with 8 per cent divinyl ben-
zene cross linkage and an exchange capacity of 1.33 meq/ml of
wet resin
(chloride form), was introduced into a 0.5 to 0.6 mm
diameter, pyrex medicine dropper to a height of 4 cm (approximately 1 ml of wet resin).
The resin was retained in the column