Nickel oxide nanoparticles/ionic liquid crystal modified carbon composite electrode for determination of neurotransmitters and paracetamol

Abstract

The ionic liquid crystal 1-butyl-1-methyl-piperidinium hexafluorophosphate and nickel oxide nanoparticles were used to construct a carbon composite electrode. This novel composite was used successfully as a sensor platform for the determination of paracetamol and some neurotransmitters such as dopamine, norepinephrine, levodopa and serotonin. Several advantages are realized in this approach due to the unique properties of nanomaterials and ionic liquid crystals, and the ease of fabrication of the carbon composite electrode. The modified sensor was evaluated and compared with nickel oxide nanoparticles/ionic liquid modified electrodes in the presence of surfactants, namely 1-n-hexyl-3-methyl imidazolium tetrafluoroborate and 1-butyl-4-methyl pyridinium tetrafluoroborate, for the electrocatalytic oxidation of paracetamol. Modification with ionic liquid crystals showed superior current signals compared to ionic liquids. The interaction of surfactants with neurotransmitters resulted in preconcentration of the drug at the ionic liquid crystal interface that allowed both ionic channeling and charge transfer mediation. Figures of merits with optimized performance are a linear dynamic range of 44.4 × 10⁻⁷–3.33 × 10⁻⁵ mol L⁻¹ for paracetamol sensing with a correlation coefficient of 0.999 and a limit of detection of 8.61 × 10⁻⁹ mol L⁻¹. The electrode was successfully employed for the direct determination of paracetamol in human urine samples, for paracetamol assay in pharmaceutical formulations and simultaneous determination of paracetamol and neurotransmitters. High reproducibility and selectivity in the presence of potential interfering species were ascertained for this electrode.