The effect of time on co-precipitation was studied.
The precipitate was allowed to stand from 1
up to 48 h. It was established that 5 h was
sufficient to produce results of good precision.
The effect of the sample volume has been studied
as well. The results obtained are listed in
Table 2. It is seen that the elements studied can be
successfully concentrated by a factor of 8–80
depending on the sample volume. This concentration
factor is sufficient to ensure the analysis of
the elements in real water samples.