Polymeric Membrane Sensor for Potentiometric Determination of Tin(II) Ions

Tin(II)-ion-selective electrode consisting of dibenzo-18-crown-6 (DB18C6) as an ionophore inPVC matrix was developed. The influences of membrane composition, selectivity, response time,reversibility and temperature on the electrode performance were investigated. The electrodeshowed a near Nernstian response for Sn2+ ions over a concentration range from 1.0× 10-6 – 1.0× 10-2 M with a slope of 27.5 ± 0.6 mV per concentration decade in a acidic solution (pH=1). Thelimit of detection was 8.0 × 10-7 M. It has a relatively fast response time and can be used for atleast 3 months without any divergence in potentials. The isothermal temperature coefficient of thiselectrode amounted to 0.0012 V/ °C. The stability constant (log Ks) of the Sn(II) – DB18C6complex was determined at 25 °C by potentiometric titration in mixed aqueous solution.