Polyeugenol-modified graphite electrode for determination of hydroquinone in cosmetic
Siti marwati(1,2), Dwi Siswanta(2), WegaTrisunaryanti(2), Isana Supiah Yosephine Louise(1)
1. Chemistry Education Department
Faculty of Mathematics and Natural Sciences
Yogyakarta State University, Yogyakarta, Indonesia
2. Chemistry Department
Faculty of Mathematics and Natural Sciences
Gadjah Mada University, Yogyakarta, Indonesia
Abstract
Graphite electrode was modified by electropolymerization of eugenol in alkaline medium by cyclic voltammetry. The polyeugenol-graphite electrode (GEEU) was than used for determination of hydroquinone (HQ) at phosphate buffer solution (PBS) of pH 7.0 by cyclic voltammetry technique. The performance of this modified has shown excellent electrocatalytic activity toward of HQ than unmodified electrode (GE). The reduction of peak separation has been decreased from 0.309 V to 0.228 V. In addition, the effect of scan rates indicate that redox electrochemical behaviour of HQ is diffusion controlled electrochemical process on GEEU. Under experimental, the oxidation peak current increases linearly with concentration of HQ at ranged from 1.42 micro M to 101.07 micro M at the linear regression equation of Ip = 3.86C + 355.20. On the other hand, the oxidation peak current raises linearly with concentration of HQ at higher ranged from 136.67 micro M to 450.50 micro M at the linear regression equation of Ip = 1.69C + 559.72. The LOD and LOQ were measured at lower concentration of HQ, 1.44 micro M and 4.37 micro M, respectively. Moreover, the proposed modified has been successfully applied to the determination of HQ in cosmetic sample with satisfactory recoveries.
Keywords: eugenol; hydroquinone; voltammetry
Topic: Fundamental and Applied Sciences