Table 1.

Calculated selectivity values for different interferents.

Interferent (X+Z)	Slope (mV/decade)	$log{K}_{Z{n}^{+2},X^{+z}}^{\mathit{\text{pot}}}$
K+1	2.40	−4.34
Co+2	4.30	−3.70
Mg+2	5.2	−4.71
Fe+3	7.6	−3.05
Na+1	7.5	−4.70
Ni+2	8.1	−4.72
Cu+2	3.6	−2.65