Selectivity coefficient K^pot_EPH,I of the constructed electrode towards interfering ions.

Interfering ions	Selectivity coefficientaKpotEPH,I
K+	3.54 × 10−4
Na+	3.84 × 10−4
Ca2+	1.27 × 10−3
Pb2+	1.30 × 10−3
Cd2+	4.10 × 10−4
Ni2+	1.40 × 10−3
Mg2+	1.10 × 10−3
Mn2+	3.20 × 10−4
Fe3+	1.70 × 10−3
Cu2+	3.80 × 10−4
NH4+	1.60 × 10−3
Co2+	3.54 × 10−4

^aAverage of three determinations.