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

Abstract

Gold nanoparticles stabilized with ionic liquid 1-dodecyl-3-methylimidazolium bromide ([C12mim]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 $\mu \text{M}$ for HQ, 0.5–200.0 $\mu \text{M}$ for CC, and 2.0–200.0 $\mu \text{M}$ for RS. Low detection limits of 0.2, 0.2, and 0.8 $\mu \text{M}$ 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.