DPV Determination of Morphine in Urine Using Self-Prepared Working Electrode of Morphine Liposome Immunosensor

A composite of nitrogen doped ordered mesoporous carbon and platinum nanoparticles was prepared and characterized by TEM. Nafion solution of the composite was dropping-plated on the surface of an Au electrade, to prepare modified electrode of Pt-N-OMC/Au. Simultaneously, liposome enclosed with the electro-active compound K₄Fe(CN)₆ was prepared, and a solution of morphine antibody was added to water-suspension of the liposome to obtain the morphine immuno-liposome. The above mentioned modified electrode, Pt-N-OMC/Au was immersed into purrole solution of the morpine immuno-liposome, and then scanned for 10 times by CV to have the morphine antibody stabilized directly on the electrode through polymerization of pyrrole, and the morphine liposome immunosensor was thus prepared and used as working electrode in the DPV determination of morphine in urine samples. It was found that in phosphate buffer solution of pH 7.0, linear relationship between values of the peak current and mass concentration of morphire was kept in the range of 1.0-500.0 μg·L^-1, with detection limit (3S/N) of 0.120 7 μg·L^-1. Recovery was tested by standard addition method giving results in the range of 95.8%-102%, and values of RSDs (n=6) found ranged from 1.5% to 4.7%.