Gold Nanoparticle Decorated Multiwall Carbon Nanotubes/Ionic Liquid Composite Film on Glassy Carbon Electrode for Sensitive and Simultaneous Electrochemical Determination of Dihydroxybenzene Isomers

Gold nanoparticles stabilized with ionic liquid 1-dodecyl-3-methylimidazolium bromide ([C
₁₂
mim]Br) as protecting agent was successfully anchored to acid treated multiwall carbon nanotubes (MWCNTs) by simple electrostatic interaction. A thin film of hybrid nanocomposite (MWCNTs-Au) was then successfully formed on glassy carbon electrode with the aid of ionic liquid N-octyl-pyridinium hexafluorophosphate. The application of the electrode for electrooxidation of dihydroxybenzene isomers was studied by cyclic voltammetry. Well-defined voltammetric peaks were obtained for a mixture of hydroquinone (HQ), catechol (CC), and resorcinol (RS) in 0.1-M PBS (pH 7.0) with a peak potential separation of 0.112 V between HQ and CC, and 0.329 V between CC and RS. Under the optimized experimental conditions, the differential pulse voltammetry current response on the fabricated electrode was linear over the wide concentration range of 0.5-110.0 μM for HQ, 0.5-200.0 μM for CC, and 2.0-200.0 μM for RS. Low detection limits of 0.2, 0.2, and 0.8 μM were obtained for HQ, CC, and RS, respectively. The developed electrochemical sensor was successfully used for the determination of dihyroxybenzene isomers in tap water sample.