Electrocatalytic Determination of Hydrazine and Phenol Using a Carbon Paste Electrode Modified with Ionic Liquids and Magnetic Core-shell Fe3O4@SiO2/MWCNT Nanocomposite

A carbon paste electrode was modified with 2( 4-Oxo-3-phenyl-3,4-dihydroquinazolinyl)-N'-phenyl-hydrazinecarbothioamide, magnetic core -shell Fe3O4@SiO2/MWCNT nanocomposite and ionic liquid (n-hexyl-3-methylimidazolium hexafluoro phosphate). The electrooxidation of hydrazine at the surface of the modified electrode was studied using electrochemical approaches. This modified electrode offers a considerable improvement in voltammetric sensitivity toward hydrazine, compared to the bare electrode. Square wave voltammetry (SWV) exhibits a linear dynamic range from 7.0 x 10(-8) to 5.0 x 10(-4) M and a detection limit of 40.0 nM for hydrazine. The diffusion coefficient and kinetic parameters (such as electron transfer coefficient and the heterogeneous rate constant) for hydrazine oxidation were also determined. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of hydrazine and phenol that makes it suitable for the detection of hydrazine in the presence of phenol in real samples.