Extractants were prepared according to the following
procedure. All dissolutions and dilutions were
performed with double deionised or distilled water.
Solution A (acetic acid, 0.11 mol l
ÿ1): 25 0.2 ml
of redistilled glacial acetic acid (or, for example,
Merck AnalaR/Suprapur grade without distillation)
was added, in a fume cupboard, to about 0.5 l of water
in a 1 l polyethylene bottle and made up to exactly 1 l
with further water. 250 ml of this solution (acetic acid
0.43 mol l
ÿ1) was diluted to 1 l to obtain an acetic acid
concentration of 0.11 mol l
ÿ1.
SolutionB (hydroxylamine hydrochloride, 0.1 mol l
ÿ1):
6.95 g of hydroxylamine hydrochloride was dissolved
in 900 ml of water. The solution was acidified with
concentrated nitric acid to pH 2.0 and made up to 1 l.
This solution was prepared on the same day as the
extraction was carried out.