Acrylic acid grafted PVC membrane based ion selective electrode for calcium and hardness measurement of water

Abstract

A poly(vinyl chloride) based membrane ion selective electrode has been developed in which acrylic acid has been grafted on poly(vinyl chloride) powder. The ion selective electrode system, prepared without an internal solution, contains DBP (plasticizer) and NaTPB (anion excluder), and shows near Nernstian response to Mg²⁺, Cu²⁺ and super-Nernstian response to Ca²⁺ in the concentration range 10⁻¹ – 10-5 mol L⁻¹. EDTA has been used to mask the interference of transition metal ions. The best performance of the electrode was obtained when it was stored in 10⁻² mol/L Ca²⁺ solution when the electrode was not in use. The electrode, with response time ≤ 20 s, has been found useful in the determination of concentration of Ca²⁺ and hardness in river water.