Simultaneous Determination of Hydroquinone and Catechol by Poly (L-methionine) Coated Hydroxyl Multiwalled Carbon Nanotube Film

Abstract: A simply and high selectively electrochemical method has been developed for the simultaneous determination of hydroquinone and catechol at a glassy carbon electrode modified with the poly L-methionine/multiwall carbon nanotubes, which significantly increased the reversible electrochemical reaction. The electrochemical behavior of catechol and hydroquinone at the modified electrode was studied by cyclic voltammetry and differential pulse voltammetry. The presence of hydroxyl MWCNTs in the composite film enhances the surface coverage concentration of poly L-methionine/multiwall carbon nanotubes. The results suggest that pH=6 is the optimum acidity condition for the selective and simultaneous determination of catechol and hydroquinone. Under the optimized condition, the response peak currents of the modified electrodes were linear over ranges of 8.0×10-7~2.0×10-4 mol/L (R2=0.997) for hydroquinone and 8.0×10-7~2.0×10-4, R2=0.997 for catechol. The sensor also exhibited good sensitivity with the detection limit of 8.0×10-8 mol/L and 1.0×10-7 mol/L for hydroquinone and catechol, respectively. This study provides a new kind of composite modified electrode for electrochemical sensors with good selectivity and strong anti-interference. It has been applied to simultaneous determination of hydroquinone and catechol in water sample with simplicity and hig