Molecularly Imprinted Electrochemical Sensor Electrodes Based on Poly-pyrrole for Sensitive Detection of Morphine in Wastewater

Morphine is an opioid extracted from poppy plant and highly effective for moderate to severe pain management. Development of techniques to measure the concentration of this highly addictive drug in various matrices is very important. This work was aimed at the development of a sensitive electrochemical method for detection of morphine in wastewater. Molecularly imprinted (MIP) electrodes were formed by elec-tro-polymerization process using pyrrole as a monomer. Electro-polymerization was performed on glassy carbon electrodes in the presence of morphine before the extraction of entrapped morphine molecules. Various techniques were employed to monitor the polymerization and response of the fabricated electrodes toward morphine. These techniques included Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS). The morphine concentration was determined using SWV by measuring the change in the redox peak current of [Fe(CN)6]3−/4− in acetate buffer. These MIP electrode sensors were used to analyze morphine concentration between 0 to 80.0 nM solution. The SWV showed a wider linear response region than cyclic voltammetry. The detection limit using SWV was found to be 1.5 nM while using cyclic voltammetry, the detection limit was 2.75 nM. This MIP electrode sensor should specificity when other closely re-lated molecules are involved and hence has potential as cheap alternative technique for analysis of morphine.