Polyeugenol-modified graphite electrode for determination of hydroquinone in cosmetic

Graphite electrode was modified by electropolymerization of eugenol in alkaline medium by cyclic voltammetry. The polyeugenol-graphite modified electrode (GEEU) was than used for the determination of hydroquinone (HQ) at phosphatbuffer solution (PBS) of pH 7.0 by cyclic voltammetry technique. The performance of this modified has shown excellent electrocatalytic activity toward HQ than an unmodified electrode (GE). The oxidation and reduction peak separation (ΔE) has been decreased from 0.309 V to 0.228 V. In addition, the effect of scanratesindicate that redox electrochemical behaviour of HQ is diffusion controlled electrochemical process on GEEU. Under experimental, the oxidation peak current(I_p) increases linearly with concentration (C) of HQ ranged from 1.42 –101.07μMat the linear regression equatian of I_p = 3.86C + 355.20 (νA, R² = 0.9989). On the other hand, the oxidation peak current also increases linearly at ranged from 136.67 – 480.50 μM at the linear regression equation of I_p = 1.69C + 559.72 (μA, R² = 0.9956). The LOD and LOQ were measured at a lower concentration of HQ,1.44μM and 4.37μM, respectively. Moreover, the proposed modified has been successfully applied to the determination of HQ in the cosmetic sample with satisfactory recoveries.