Fabrication of a Nizatidine–Selective PVC Membrane Potentiometric Sensor in Biological Samples and Its Greenness Assessment

In this study, a selective potentiometric sensor was developed for nizatidine, a widely used drug for the treatment of various gastric disorders. Initially, the nizatidine–tetraphenylborate (NZ–TPB) ion pair was synthesized and subsequently incorporated as the electroactive sensing material in polymeric membrane sensors. The optimal membrane composition was determined to be 3.0% NZ–TPB ion pair, 32.0% poly(vinyl chloride) (PVC), and 65.0% o-nitrophenyl octyl ether (o-NPOE). Water layer tests were performed on the prepared sensor, and its surface morphology was examined using scanning electron microscopy (SEM). The developed nizatidine-selective potentiometric sensor exhibited a linear response over the concentration range of 1.0×10-2–1.0×10-5 M, with a detection limit of 5.91×10-6 M. The sensor exhibited a stable performance over a pH range of 4.0–10.0, with an average response time of approximately 10 s. he proposed sensor was successfully applied to the determination of nizatidine in fetal bovine serum (FBS) samples, achieving satisfactory recoveries of up to 96.70%. In addition, the environmental sustainability of the method was comprehensively assessed using AGREE and GAPI green analytical evaluation tools.