Study On Electrochemical Sensors Of Morphine

In this work, two electrochemical sensors were prepared for the amperometric detection of morphine. Morphine was incorporated into a molecularly imprinted polymer (MIP). MIP particles were prepared and characterized by UV-VIS-NIR spectroscopy and scanning electron microscope. Ordered mesoporous carbon (OMC) was synthesized and characterized by Nitrogen adsorption-desorption isotherm, powder XRD and FT-IR spectra. A stable suspension of ordered mesoporous carbon (OMC) was obtained by dispersing the OMC in a solution of Nafion. The suspension of OMC/Nafion was characterized by scanning electron microscope.Electropolymerization and titration methods were used to modify GC electrode with MIP particles. By coating the suspension onto the GC electrode, Nafion/OMC/GC electrode was prepared. The electrochemistry behaviors of the electrodes modified by MIP and OMC were studied, respectively.The oxidizing current of the MIP modified is measured in a KCl solution (pH 6.22 ) at 0.675V (vs. Ag/AgCl/ sat'd KCl) with morphine concentration varying in the 0.2-2 mM range. The sensitivity of 171.38μA/cm²mM (R=0.99) is obtained. The detection limit of 0.025mM at a signal-to-noise of 3 is achieved.Nafion-OMC/GC electrode exhibits strong and stable electrocatalytic response toward morphine, which shows a large determination range (4×10^-9-4×10^-4) mol L^-1) and a remarkably low detection limit (1.5ng).The results show that both two modified electrodes can electrocatalysis oxidation of morphine. These modified electrodes can be used as morphine sensor.