Electrochemical Determination of Hematoxylin by Pretreated ZnO Nanoflakes Modified Carbon Paste Electrode in the Absence and Presence of Eosin Y

Abstract

Hematoxylin (HX) is a bioactive flavonoid and biologically important species. It is generally present in plants. HX undergoes electrochemical oxidation at the electrode surface. Here, the prepared zinc oxide (ZnO) nanoflakes were used for the modification of carbon paste electrode (CPE) and the electrode surface was pretreated in the presence of NaOH (pre-ZnO/CPE) using cyclic voltammetry. The pre-ZnO/CPE has shown outstanding electrochemical sensitivity towards the oxidation of HX. The effects of pH and scan rate for electrochemical oxidation of HX were studied. The performance of pre-ZnO/CPE for HX in the absence and presence of EY (Eosin Y) was also investigated. No interference was found for the determination of HX in the presence of EY, at the potential range of −0.1 to 0.5 V vs SCE. Moreover, the sensitivity of HX increased in the presence of EY at pre-ZnO/CPE. The differential pulse voltammetry was used to determine the various concentrations of HX in the absence and presence of EY, respectively. The detection limit of HX was 1.68 μM in the absence of EY, and 0.43 μM in the presence of EY. We demonstrate that pre-ZnO/CPE can be used as a promising sensor for the electrochemical detection of HX.