A New Potentiometric Fluconazole-Selective Sensor Based on a Molecularly Imprinted Polymer

Fluconazole (FLU) is a widely used antifungal drug, and its reliable determination is important for quality control in pharmaceutical analysis. This study aimed to develop a simple and accurate FLU-selective potentiometric sensor based on a molecularly imprinted polymer (MIP). The prepared MIP was evaluated by FT-IR spectroscopy and TG/DSC analysis. The sensor was characterized using direct potentiometry. The influence of membrane composition on sensor response was investigated by varying the MIP content and plasticizer type. The optimized sensor contained 12.5% MIP and dibutyl sebacate as the plasticizer. It exhibited a near-Nernstian response with a slope of 56.1 mV/decade of activity, a wide measuring range (1.0 × 10−7–1.0 × 10−3 M), and a low limit of detection (7.5 × 10−8 M). Additionally, it showed a fast response (5 s), low signal drift (−0.6 mV/h), and excellent selectivity attributed to the recognition properties of the MIP. The sensor applicability was confirmed by FLU determination in standard solutions and pharmaceutical samples using direct potentiometry and the Gran method. Both approaches provided acceptable results, while the Gran method showed slightly better agreement with the expected FLU concentrations, with recoveries within ±10%. The developed sensor enables reliable FLU determination in pharmaceutical samples.