Electrochemical study of a self-assembled monolayer of N,N′-bis[(E)-(1-pyridyl) methylidene]-1,3-propanediamine formed on glassy carbon electrode: preparation, characterization and application

Abstract

Preparation of N,N′-bis[(E)-(1-pyridyl) methylidene]-1,3-propanediamine (PMPD) self-assembled monolayer (SAM) on a bare glassy carbon electrode (GCE) for the determination of hydroxychloroquine (HCQ) is described. Characterizing the GC-PMPD SAM modified electrode was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using the [Fe(CN)₆]^3−/4− redox couple. Surface coverage (θ) and surface pK_a were also calculated using CV and EIS. Cyclic voltammograms of bare GC and the GC-PMPD SAM electrodes showed that the kinetics of HCQ on the last electrode was quicker than that of the bare GCE. On the other hand, the presence of PMPD at the electrode surface, reduces the over potential of HCQ oxidation by −46 mV. The relationship between the oxidation peak current and HCQ concentration showed two linear dynamic ranges of 0.05–12.28 μM and 12.28–111.11 μM with a detection limit of 4.51 nM (signal to noise = 3). The results showed that the GC-PMPD SAM electrode could be employed for the determination of HCQ in real samples such as pharmaceutical formulations and human serum samples.