3.6. Effect of foreign ions
To investigate the effect of various cations found in natural samples,
elements representing alkaline, alkaline earth, and transition
metals were added to 100 mL of solution containing 0.01 mg cadmium
and 0.01 mg copper ions. The degree of tolerance for some
alkaline, alkaline earth and transition metal ions are presented in
Table 3. From the tolerance data, it can be seen that the foreign
ions have no significant effects on preconcentration of cadmium
and copper ions at pH 6.0.