Simultaneous determination of methadone and morphine at a modified electrode with 3D β-MnO 2 nanoflowers: application for pharmaceutical sample analysis.

The present research synthesized manganese dioxide nano-flowers (β-MnO 2 -NF) via a simplified technique for electro-catalytic utilization. Moreover, morphological characteristics and X-ray analyses showed Mn in the oxide form with β-type crystallographic structure. In addition, the research proposed a new efficient electro-chemical sensor to detect methadone at the modified glassy carbon electrode (β-MnO 2 -NF/GCE). It has been found that oxidizing methadone is irreversible and shows a diffusion controlled procedure at the β-MnO 2 -NF/GCE. Moreover, β-MnO 2 -NF/GCE was considerably enhanced in the anodic peak current of methadone related to the separation of morphine and methadone overlapping voltammetric responses with probable difference of 510 mV. In addition, a linear increase has been observed between the catalytic peak currents gained by the differential pulse voltammetry (DPV) of morphine and methadone and their concentrations in the range between 0.1-200.0 μM and 0.1-250.0 μM, respectively. Furthermore, the limits of detection (LOD) for methadone and morphine were found to be 5.6 nM and 8.3 nM, respectively. It has been found that our electrode could have a successful application for detecting methadone and morphine in the drug dose form, urine, and saliva samples. Thus, this condition demonstrated that β-MnO 2 -NF/GCE displays good analytical performances for the detection of methadone.