Simultaneous Determination of Hydroquinone and Catechol with Poly(glutamic acid) Modified Electrode
Glassy carbon electrode was modified with poly (glutamic acid) films by electrochemical polymerization of glutamic acid monomer. Poly(glutamic acid) films showed good adherence to the electrode surface. The effects of various experimental. conditions such as polymerization potential, circles and scan rate were studied as for the electrochemical polymerization process. The performance of modified electrode was characterized by cyclic voltammetry (CV). Poly (glutamic acid) modified electrode showed an excellent electrocatarytic ability towards the redox of hydroquinone and catechol with a decrease of the overpotential and the improvement of the redox peak current. In 0. 1 mol/L PBS (pH 7. 0), hydroquinone and catechol could be simultaneously determined on the modified electrode by CV and differential pulse votammetry (DPV) techniques. The DPV response of two compounds increased linearly with the concentration in the range of 5.0 X 10(-6) -1. 0 X 10(-4) mol/L, and the detection limits (S/N=3) were 1. 0 X 10(-6) mol/L. Moreover, the modified electrode exhibited good repeatability and long-time stability. It was successfully used to determine hydroquinone and catechol in waste water samples with recoveries between 99. 6% and 103. 3% and the relative standard derivations (RSD) between 1. 2% and 2. 3%.