Moreover, the pond water sample was divided into 30 samples
containing different concentrations of 4 metal ions, in the case of
both single and mixed metal ions. The metal ion concentrations
in each water sample were then determined by naked-eye andcompared the obtained results with ICP determination. The qualitative
percentage errors between both methods were found to be
30%, 21% and 3% for Pb(II), Al(III) and Fe(III), respectively. In addition,
the quantitative errors were found to be 30%, 23% and 7% for
Pb(II), Al(III) and Fe(III), respectively. However, the percentage error
for Cu(II) detection was not found in terms of qualitative and
quantitative determinations.