Construction of New Coated Carbon Electrodes for Determination of Sildenafil Citrate Drug

In this research, new coated carbon electrodes were constructed and used for the determination of Sildenafil citrate (SILC) drug. The electrodes were constructed by preparing ion-pair for (SILC) with phosphotungstic acid (PTA) or phosphomolybdic (PMA) acid using dibutyl phthalate (DBP) as a plasticizer. These electrodes showed good sensitivity towards SILC with linear range of (1.010 -7 -1.010 -2 ) M, correlation coefficient, (0.9990), the life time (120) days, optimum temperature range (23-65) o C and optimum pH range (2-5) for both electrodes, limit of detection (5.05510 -8 and 5.11610 -8 ) M, slope (57.29 and 59.10) mV/decadefor SILC-PTA and SILC-PMA electrodes respectively. These electrodes were successfully applied for determination of SILC in pure and pharmaceutical preparation form(tablets) with recovery of not less than 98%.