Design of a New Maprotiline-Selective Potentiometric Sensor Based on Metal-Organic-Framework/Imprinted Polymer Composite with Ultra-Broad Dynamic Range and Nanomolar Detection Limit

Abstract

This study presents the development of a novel ion-selective electrode (ISE) for the selective and sensitive potentiometric detection of maprotiline (MAP). Due to the limited number of electrochemical maprotiline-selective sensors in the literature and the lack of molecularly imprinted polymer (MIP)-based potentiometric sensors, this study employed a MAP-imprinted polymer/metal organic framework (MIP/MOF) hybrid material as the ionophore component in the membrane structure of the MAP-selective electrode for the first time. For the design of the sensor, a europium oxide metal-organic cage (Eu-MOF)-based MIP (Eu-MOF@MAP-MIP) was synthesized, which offers advantages for molecular imprinting due to its large surface area, tunable pore architecture, and adaptable chemical functionality. The sensor exhibited a wide linear operating range from 1.0 x 10-10 to 1.0 x 10-2 M, a near-Nernstian slope of 52.3 mV/decade, and a remarkably low detection limit of 9.0 x 10-11 M. The analytical applicability was demonstrated by using it as an indicator electrode in the potentiometric titration of MAP and by directly determining the MAP content in two commercial drug formulations. The obtained high recovery percentages solidly confirm the practical suitability and high accuracy of the developed sensor for MAP analysis in real and complex matrices.