Gold Nanoparticles–Fe3O4 Beads/multiwalled Carbon Nanotubes Modified Glassy Carbon Electrode as a Sensing Platform for the Electrocatalytic Determination of Loratadine in Biological Fluids

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The glassy carbon electrode was modified by gold nanoparticles (AuNps)–Fe₃O₄ beads/multiwalled carbon nanotubes (MWCNTs). Surface morphology characterization of the bare and modified electrodes was characterized by scanning electron microscopy technique. This modified glassy carbon electrode was applied for electro-catalytic determination of loratadine. The modified electrode lowered the reduction overpotential of loratadine with the enhancement of its peak current; this behavior was attributed to the electro-catalytic activity of the modified electrode toward loratadine electro-reduction. Various parameters, such as pH of the working solution, amounts of MWCNTs, Fe₃O₄ beads and AuNps affecting the electrochemical performance of the modified electrode toward loratadine determination were optimized. The linear response of the modified electrode toward loratadine concentration using hydrodynamic amperometry method was between 0.05–5 μM with a detection limit of 0.04 μM (S/N = 3). The modified electrode figures of merit were high repeatability, reproducibility, long-term life time and low response time (<3 s). The practicability of this proposed method was examined by loratadine content quantification in commercial pharmaceutical samples, human blood serum and urine samples and satisfactory results were obtained.