Fabrication of electrochemical sensor based on molecularly imprinted polymer and nanoparticles for determination trace amounts of morphine

A simple and rapid electrochemical method developed for the detection of trace amounts of morphine (MO) at the surface of modified pencil graphite electrode (PGE) with multiwall carbon nanotubes (MWCNTs), molecularly imprinted polymer (MIP), and gold nanoparticles (AuNPs).Various types of electrochemical methods containing cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were employed to probe the characteristics of the constructed electrode toward morphine. After optimization of several effective parameters, the calibration curve by SWV was linear in two linear domains, over the range of 0.008 to 5 mu mol L-1 vs. Ag/AgCl, and the detection limit was 2.9 nM. The relative standard deviation (RSD) for six replicate determinations of 0.05 mu mol L-1 MO was found to be 2.57 % (S/N = 3). Finally, the ability of the electrochemical sensor was successfully applied for MO determination in real samples such as human urine and plasma.