Simultaneous determination of dihydroxybenzene isomers using disposable screen-printed electrode modified by multiwalled carbon nanotubes and gold nanoparticles

A disposable electrode, modified with multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs), was developed to serve as a sensor for the simultaneous determination of dihydroxybenzene isomers (hydroquinone, catechol and resorcinol). The modified electrode was fabricated by electrodepositing AuNPs on a MWCNTs decorated screen-printed electrode (SPE), then it was characterized in morphology and electrochemical properties and utilized to determine the isomers of dihydroxybenzene in water samples. Compared with bare SPE, AuNPs-modified SPE, and MWCNTs-modified SPE, the fabricated SPE has much stronger electrocatalytic activity for the oxidation of dihydroxybenzenes with the increase of the peak current and the decrease of the potential difference (△E_p) between the anodic and cathodic peaks. By using differential pulse voltammetry (DPV), the three isomers can be determined simultaneously and sensitively at the modified SPE. For hydroquinone, catechol and resorcinol, the oxidation peak currents are linear to the concentrations at the range of 2.0 × 10^-6∼7.3 × 10^-4 M, 2.0 × 10^-6∼7.3 × 10^-4 M and 3.0 × 10^-6∼9.6 × 10^-4 M with the detection limits of 3.9 × 10^-7 M, 2.6 × 10^-7 M and 7.2 × 10^-7 M, respectively. Moreover, a rapid on-filed determination is convenient to be performed at this disposable modified SPE incorporated in a portable electrochemical system. These results reveal that the presented sensor can be used for the simultaneous and sensitive on-field determination of dihydroxybenzene isomers.