Symmetric and Asymmetric PVC Membrane Potentiometric Electrodes for the Analysis of Morphine Hydrochloride

Two novel potentiometric Morphine sensors were designed, optimized and used for the determination of this alkaloid drug. The electrodes were based on the symmetric and asymmetric designs for the application of PVC membrane sensors. Both the symmetric membrane and the asymmetric wire coated electrodes were worked based on morphine-tetraphenyl borate ion-pair complexes which act as the sensing material and they responded based on ion exchange mechanism. The optimal response behavior was at 5% wt. of the ion-pair, 30% wt. of PVC and 65% wt. of DBP for the symmetric devices and at 25% wt. of PVC, 5% wt. of the ion-pair morphine-tetraphenyl borate, 2% wt. of ionic additive and 68% DBP. The PVC membrane sensor was found to have a Nernstian behavior in the concentration range of 5.0×10-5-1.0×10-2 mol L-1, while the wire coated electrodes showed linear behaviors from 1.0×10-7 to 1.0×10-4 mol L-1. Both devices proved to satisfactorily applicable in the analysis of Morphine hydrochloride in pharmaceutical formulation under laboratory conditions.