A novel nanoporous film electrode based on electrochemical polymerization of ionic liquid and its application in sensitive determination of magnolol

A polymeric film modified glassy carbon electrode was electrochemically fabricated with potential step technique using 1-butyl-3-[3-(N-pyrrole)propyl] imidazolium tetrafluoroborate ionic liquid as a monomer. Followed by being treated with sodium dodecyl sulfonate solution, a hydrophobic film bearing poly{1-butyl-3-[3-(N-pyrrolyl)propyl]imidazolium dodecyl sulfonate} moiety was modified onto electrode surface. The substitution was confirmed by X-ray photoelectron spectroscopy. The morphology of the polymeric film electrode surface was characterized with scanning electron microscopy. Electrochemical behaviors of magnolol at the hydrophobic polymeric film electrode were systematically investigated with voltammetry. Compared with the unmodified glassy carbon electrode, the oxidation peak shift slightly towards positive potential and the oxidation peak current significantly increased. Under optimal conditions, the oxidation peak current was linearly related to the magnolol concentration in the range of 1.0×10–8 to 1.0×10–6 mol L–1 and 1.0×10–6 to 5.0×10–5 mol L–1. The detection limit was estimated to be 4.55×10–9 mol L–1 (S/N=3). The polymerized ionic liquid film electrode was successfully used to analysis magnolol in M. officinalis. The result was consistent with that obtained by high performance liquid chromatography.