Parameters Sensors Sensor 1 Nf-ST Sensor 2 Nf-SM Sensor 3 Nf (ST+SM) Composition (W/W%) 3.0% (I.P) +55.0% G + 42.0% P 3.0% (I.P) +55.0% G+ 42.0% P 2.5 % (ST) (I.P)+ 0.5 % (SM) (I.P)+55.0% G+42.0% P Slope (mV/decade) -59.0 ± 0.5 -58.5 ± 0.5 -60.5 ± 0.5 Correlation coefficient (r) 0.996 0.999 0.998 LOD (M) 1.25x10-8 4.00x10-8 1.00x10-8 Linear range (M) 2.50x10-8-1.00x10-3 5.00x10-8-1.00x10-3 1.25x10-8-5.00x10-2 Working pH range 2.0–6.0 2.0–6.0 2.0–6.0 Response time (s)  ≤ 5 s  ≤ 5 s  ≤ 5 s Recovery (%) ± S.D* 99.12 ± 0.5 98.55 ± 0.5 99.25 ± 0.5 Robustness 99.65 ± 0.5 99.37 ± 0.5 99.87 ± 0.5 Ruggedness 99.75 ± 0.5 99.45 ± 0.5 99.75 ± 0.5 * Five replicates

Table 2: Response characteristics of the Ns-ion exchangers at 95% confidence intervals, average of five replicates at 25.0 ± 0.1°C.