A highly dispersed multi-walled carbon nanotubes and poly(methyl orange) based electrochemical sensor for the determination of an anti-malarial drug: Amodiaquine

Abstract A glassy carbon electrode modified with electrochemically polymerized methyl orange (PMO) and multi-walled carbon nanotubes (MWCNT) was developed. The morphologies of the fabricating materials (PMO and MWCNT) were investigated by field-emission scanning electron microscopy (FE-SEM). The designed sensor was used for the sensitive determination of amodiaquine (AQ), an anti-malaria drug. AQ was developed as an alternative to chloroquine because of its activity against chloroquine-resistant Plasmodium falciparum ( P. falciparum ) parasites. The modified electrode was employed to study the electrochemical oxidation of AQ using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Under optimal experimental conditions, DPV exhibited a linear response in the concentration range from 1.0 × 10 −7 to 3.5 × 10 −6  mol L −1 with a limit of detection (LOD) of 8.9 × 10 −8  mol L −1 . Furthermore, the number of electrons and protons involved in the electrochemical study of AQ was also calculated and a plausible mechanism for the electro-oxidation of AQ was deduced. The developed sensor demonstrated analytical applicability as it was successfully employed to determine the drug AQ in pharmaceutical formulations and human urine samples.