Polystyrene Based Silver Selective Electrodes

Abstract: Silver(I) selective sensors have been fabricated from polystyrene matrix membranes containing macrocycle, Me₆(14) diene.2HClO₄ as ionophore. Best performance was exhibited by the membrane having a composition macrocycle : Polystyrene in the ratio 15:1. This membrane worked well over a wide concentration range 5.0×10^-6–1.0×10^-1M of Ag⁺ with a near-Nernstian slope of 53.0 ± 1.0 mV per decade of Ag⁺ activity. The response time of the sensor is <15 s and the membrane can be used over a period of four months with good reproducibility. The proposed electrode works well in a wide pH range 2.5-9.0 and demonstrates good discriminating power over a number of mono-, di-, and trivalent cations. The sensor has also been used as an indicator electrode in the potentiometric titration of silver(II) ions against NaCl solution. The sensor can also be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of Ag⁺ in solution having up to 25% (v/v) nonaqueous fraction.