Phenylpropanolamine Analysis in Formulation and Urine by Potentiometric Membrane Sensor. Theoretical investigation

This research introduces the design of an ion-pair based PVC membrane sensor for the phenylpropanolamine (PPA) determination based on some theoretical investigations. For the membrane preparation, phenylpropanolamine-tetraphenylborate ion-pair was employed as an electroactive material in the PVC membrane. Also, several plasticizers were studied namely, dibutyl phthalate (DBP), benzyl acetate (BA), nitrobenzene (NB). After a series of experiments, the best electrode performance was accomplished with a membrane composition of 30% PVC, 65% DBP, 5% ion-pair. This electrode illustrated a fast (~5 s), stable and Nernstian response (55.9±0.4 mV/decade) across a relatively wide phenylpropanolamine concentration range (1×10 -5 to 1×10 -2 M), in the pH range of 4.5–6.0. Validation of the method shows suitability of the sensors for applies in the quality control analysis of phenylpropanolamine hydrochloride in pharmaceutical formulation and urine. The proposed method was found to be simple, accurate and precise which can be used as a detector for HPLC.