Overoxidized Polypyrrole/ Gold Nanoparticles Composite Modified Screen-Printed Voltammetric Sensor for Quantitative Analysis of Methadone in Biological Fluids

A highly sensitive voltammetric sensor for quantitative analysis of methadone in biofluids is introduced. The proposed sensor is based on screen-printed electrode (SPE) modification with overoxidized polypyrrole and gold nanoparticles composite (AuNPs/PPyox/SPE). Electrochemical measurements were carried out using square wave voltammetry (SWV). Morphological and electrochemical characterization of the proposed composite were studied using field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry. A wide linear range of 1 to 120 μmol L-1 and the limit of detection of 0.45 μmol L-1 in methadone analysis obtained by the presented sensor. The proposed sensor shows proper stability and high sensitivity in quantitative analysis of standard samples and can be successfully used for methadone determination in biological fluids.