Sensitive simultaneous determination of catechol and hydroquinone using a gold electrode modified with carbon nanofibers and gold nanoparticles

A highly sensitive electrochemical sensor for the simultaneous determination of catechol (CC) and hydroquinone (HQ) was fabricated by electrodeposition of gold nanoparticles onto carbon nanofiber film pre-cast on an Au electrode. Both CC and HQ cause a pair of quasi-reversible and well-defined redox peaks at the modified electrode in pH 7.0 solution. Simultaneously, the oxidation peak potentials of CC and HQ become separated by 112 mV. When simultaneously changing the concentrations of both CC and HQ, the response is linear between 9.0 mu M and 1.50 mM. In the presence of 0.15 mM of the respective isomer, the electrode gives a linear response in the range from 5.0 to 350 mu M, and from 9.0 to 500 mu M for CC and HQ, respectively, and detection limits are 0.36 and 0.86 mu M. The method was successfully examined for real sample analysis with high selectivity and sensitivity.