Potentiometric Determination of Loperamide Hydrochloride by Loperamide PVC Membrane and Nano-Composite Electrodes

In this work, two new loperamide potentiometric electrodes were prepared and used for pharmaceutical analysis. In case of liquid membrane electrode, the best results were obtained from the electrode with the membrane composition of 5% ion-pair, 1% NaTPB, 30% PVC, and 64% DBP. The proposed sensor shows a Nernstian response (slope of 57.2 mV per decade) in the range of 3.0×10-5-1.0×10-2 mol L-1. In case of carbon paste electrode modified by MWCNTs, calibration graph slope is about 58.5 mV per decade in the concentration range of loperamide hydrochloride 1.0×10-5-1.0×10-2 mol L-1. Both sensors work well in the laboratory conditions and successfully applied in analysis of loperamide in some pharmaceutical formulations.