High sensitive simultaneously electrochemical detection of hydroquinone and catechol with a poly(crystal violet) functionalized graphene modified carbon ionic liquid electrode

By using potentiostatic method a poly(crystal violet) (PCV) and graphene (GR) composite was electrodeposited on the surface of carbon ionic liquid electrode (CILE) to obtain the modified electrode (denoted as PCV-GR/CILE). Due to the synergistic effects of PCV and GR, the fabricated electrode exhibited good electrochemical performances with increased conductivity and decreased interfacial resistances. Electrochemical behaviors of hydroquinone (HQ) and catechol (CC) were investigated on PCV-GR/CILE by cyclic voltammetry, which gave the separation of the oxidation peak potential of 112 mV in pH 2.0 phosphate buffer solution. So the modified electrode was suitable for simultaneous electrochemical determination of HQ and CC in the mixture. Under the optimal conditions, the oxidation peak currents were proportional to the concentration of HQ in the range from 0.02 μmol/L to 600.0 μmol/L with the detection limit as 0.0062 μmol/L (3σ), and to that of CC in the range from 0.04 μmol/L to 600.0 μmol/L with the detection limit as 0.013 μmol/L (3σ). When simultaneously changing the concentration of the two isomers, the linear range was from 0.12 μmol/L to 600.0 μmol/L for HQ and 0.36 μmol/L to 600.0 μmol/L for CC with the detection limit as 0.033 μmol/L (3σ) and 0.097 μmol/L (3σ), respectively. The fabricated PCV-GR/CILE was further used to detect HQ and CC in artificial water sample with satisfactory results.