Development of highly selective and sensitive molecularly imprinted polymer-based electrochemical sensors for tolvaptan assay in tablets and serum

Abstract

In this research, two different molecularly imprinted polymer (MIP)-based electrochemical sensors were proposed for the determination of tolvaptan (TOL). Photopolymerization (PP) and thermal polymerization (TP) techniques were developed for the determination of TOL. The advantages of MIP were used to design an electrochemical sensor for selective and sensitive determination of TOL. TOL was determined on a glassy carbon electrode (GCE) using differential pulse voltammetry (DPV) for both techniques. Some important parameters affecting the sensor efficiency, such as template/monomer ratio, PP and TP time, drop volume, removal solutions, removal and rebinding time, etc., were optimized. The surface characterization of the proposed MIP-based electrochemical sensors was carried out with electrochemical characterization by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. It was extended with the scanning electron microscopy (SEM) technique. Under optimal conditions, the developed sensors showed good linearity between 1.0 × 10⁻¹¹ M and 1.0 × 10⁻¹⁰ M, and 2.5 × 10⁻¹¹ M and 2.5 × 10⁻¹⁰ M for PP and TP, respectively. Low detection limits (2.89 × 10⁻¹² M (PP) and 1.88 × 10⁻¹³ M (TP)) were also obtained for TOL determination. The applicability of the proposed sensor was evaluated using tablet and commercial human serum samples. Interference and imprinting factor studies verified the selectivity and specificity of the proposed sensors, and the efficiency of the sensors was verified using an unprinted polymer for comparison at each step.