Self-Reporting Molecularly Imprinted Polymer with Covalently Immobilized Ferrocene Redox Probe for Selective Electrochemical Sensing of P-Synephrine

Abstract

Simultaneously, the p-synephrine 1 template was imprinted, and a ferrocene redox probe was covalently immobilized in a (bis-bithiophene)-based polymer, and the resulting molecularly imprinted polymer (MIP) was deposited on the Pt electrode as a thin film to form a redox self-reporting MIP film-based chemosensor. After subsequent template extraction from the film, analyte 1 was determined with differential pulse voltammetry (DPV) in a (redox probe)-free solution. That was possible because the internal ferrocene redox probe generated the DPV analytical signal. The thickness and morphology of the film were crucial for the sensor's performance. The self-reporting mechanism was examined with electrochemical techniques, simultaneous piezomicrogravimetry and electrochemistry at an electrochemical quartz crystal microbalance, and surface plasmon resonance spectroscopy. The chemosensor was applied for selective p-synephrine determination in a concentration range of 2.0-75 nM with the LOD of 0.57 nM at S/N = 3.