Multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-graphene hybrid composite film for simultaneous determination of catechol and hydroquinone

• PDDA maintains electronic structure of GR and MWCNTs and prevents GR coagulation.
• MWCNTs-PDDA-GR owns high surface area, excellent catalytic activity and conductivity.
• MWCNTs-PDDA-GR/GCE exhibits good sensitivity, selectivity and reproducibility toward HQ and CC.

A multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-graphene modified glassy carbon electrode (MWCNTs-PDDA-GR/GCE) has been fabricated and used for simultaneous determination of catechol (CC) and hydroquinone (HQ). Transmission electron microscopy (TEM) and electrochemical impedance spectroscopy (EIS) results revealed that MWCNTs-PDDA-GR was successfully prepared with enhanced electron transfer ability. Differential pulse voltammetry (DPV) results showed that MWCNTs-PDDA-GR/GCE exhibited an excellent electrochemical performance, two correspondingly well-defined oxidation peaks with significantly different peak potentials (120 mV) and enhanced peak currents appeared at the modified electrode. Under the optimized conditions, the sensing platform showed wide linear responses for HQ and CC from 5.0 × 10−7 to 4.0 × 10−4 mol L−1 with detection limits (S/N = 3) of 2.0 × 10−8 mol L−1 and 1.8 × 10−8 mol L−1, respectively. The proposed MWCNTs-PDDA-GR/GCE proved successful toward the sensitive and simultaneous detection of HQ and CC in practical water samples.