Voltammetric Determination of Hydroquinone in Water Samples Using Platinum Electrode Modified with Poly(Alizarin Red S)

The presented work focused on the preparation of a voltammetric sensor for hydroquinone (HQ) determination using a polycrystalline platinum electrode modified with Alizarin Red S (ARS). The electrode was prepared by electropolymerization of ARS on a platinum electrode through the application of 100 cyclic voltammetric segments between –0.4 and 1.2 V against Ag/AgCl (quasi-reference electrode). The modified poly (ARS)-Pt electrode was characterized in terms of stability and cyclic voltammetric behavior as a sensor for HQ in aqueous media. The modified electrode showed excellent stability and higher current than the unmodified electrode for the electrooxidation of HQ. Thus, the oxidation of HQ at poly (ARS)-Pt electrode exhibits notable electrocatalytic performance. The limit of detection is 0.16 µM, and the standard curve exhibits a linear relationship over the range from 0.25 to 15 µM (R² = 0.999). Investigation of the response to some potential interferences indicated that the electrode is unresponsive to Na⁺, K⁺, Mg²⁺, Ca²⁺, Zn²⁺, Mn²⁺, Mo²⁺, Co²⁺, Bi²⁺, Cd²⁺, Ni²⁺, Al³⁺, \({\text{NO}}_{3}^{ - }\), \({\text{SO}}_{4}^{{2 - }}\), Cl^–, phenol and resorcinol, but shows marginal change towards Hg²⁺ and Cu²⁺. Recovery tests indicated recovery values between 97.0% and 100.81% when analyzing real samples at the modified electrode.