Atenolol ion selective electrodes have been prepared based on phosphotungistic acid using many plasticizers which were:Di-butylphosphate (DBP), Tri-butylphosphate (TBP),o-nitrophenyloctylether (ONPOE) and Di-octylphthalate (DOP).The properties of the prepared electrodes have been studied including: slope, concentration range, detection limit, life time, and pH effect.The electrodes no. (I,II and III) of (DBP, TBP and ONPOE) respectively, gave a linear range from (1x10-4-5x10-1, 1x10-4-5x10-2 and 1x10-4-1x10-2 )M respectively, with slopes of (34.63, 35.16 and 64.07) mV/decade. The limit of detection was (1.1x10-5, 1.8x10-6 and 1.1x10-4) M and the lifetime were about (35 day, 45 day and ~ 48 hours) respectively.The fourth membrane was based on (DOP), displays linear range from 1x10-4M to 5x10-2M with a Nernstian slope of 55.91 mV /decade and correlation coefficient 0.9994. The limit of detection was 5x10-5M and the life time was ~90 day.The stability of the four electrodes was monitored continuously and evaluated; the standard deviation of potential drift obtained were ≤ (2,3,8 and0.5) mV/day for membrane no. (I,II,III and IV) respectively.From the optimization and working pH results, it is very clear that the electrodes (IV) based on DOP plasticizer give the best result; so, it has been chosen as the best combination of plasticizer and electro-active compound.The practical utility of the electrode has been demonstrated by use it as indicator electrode in potentiometric precipitation titration of atenolol solution with phosphotungistic acid solution. Standard addition method has been also successfully applied and presenting an excellent results.The proposed electrode was successfully applied to the determination of atenolol in pharmaceutical preparation. The analytical method proposed proved to be a simple, rapid and good accuracy.
