A Novel Electrochemical Sensor Based on Graphene Oxide Nanosheets and Ionic Liquid Binder for Differential Pulse Voltammetric Determination of Droxidopa in Pharmaceutical and Urine Samples

Abstract

Droxidopa is a synthetic amino acid that undergoes conversion to the potent vasoconstrictor norepinephrine in the presence of aromatic amino-acid decarboxylase and pyridoxal phosphate. It is effective for the treatment of frozen gait and dizziness on standing associated with Parkinson’s disease and for the treatment of orthostatic hypotension. In the present work, the anodic oxidation of droxidopa at the surface of novel carbon paste electrode adjusted with ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate) and graphene oxide (GOILCPE) was studied. The structure of the modified electrode was examined via SEM. The electrochemical discernment of the modified electrode was conducted via cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV). DPV demonstrates a linear response within the 1.0 × 10^–7 to 6.0 × 10^–4 M range for droxidopa. A detection limit of 3.0 × 10^–8 M was obtained. Finally, the modified electrode was applied with success for the accurate detection of droxidopa content within real samples.