The Potentiometric Analysis of Chloride Ion Using Modified Heterogeneous Chitosan Membranes

The potentiometric chloride ion selectivity of a polymer membrane based on PVC and chitosan as an active material was investigated. Two dipping solutions were chosen, KCl and FeCl3 solution. The selectivity coefficients, K pot A,B, for some anions determined by chitosan–ClPotBA,– membrane were in the sequence of Br– ≈ I– HCO3– NO3– OH– SO42– C2O42–, with values 0.03 to 0.28 (Log KPot A,B= –1.3 to –0.55) and in the order of COBA,32– HCO3– ≈ F– ClO3– ≈ I– NO3– ≈ IO3– Br– SO42– OH–, with values 0.01 to 0.28 (Log K POT a,b = –2.0 to –0.55) for chitosan–FePotBA,3+ membrane. The linear concentration ranges for both membranes were 1.0 x 10–4 – 1.0 x 10–1 M Cl–. The optimum pH were 6.5 ± 1.0 and 5.0 ± 1.0 for chitosan–Cl– and chitosan–Fe3+, respectively. There is no significant changes in performance within 60 days for chitosan–Cl– and 42 days for chitosan–Fe3+. The proposed membrane electrodes showed good agreement with a commercial electrode with correlation coefficient, r, 0.9560 and 0.9621 for chitosan–Cl– and chitosan–Fe3+, respectively.