Electrochemical Determination of Dopamine Using Polyphenol Oxidase from Corn Tassels: Development and Application in Pharmaceutical Analysis

OpenAlex İngilizce

This work describes the development of a polyphenol oxidase (PPO)-based electrochemical biosensor for the sensitive and selective determination of dopamine. PPO was extracted from corn tassels and immobilized onto a glassy carbon electrode (GCE), forming a cost-effective and sustainable sensing platform. The biosensor was optimized with respect to pH, temperature, and applied potential. The optimal response was obtained at pH 4.0 and 30 °C with an applied potential of +0.05 V. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) revealed enhanced electrocatalytic activity of the PPO-modified electrode compared with the bare GCE, while electrochemical impedance spectroscopy (EIS) confirmed improved charge transfer properties. Under the optimized conditions, the biosensor exhibited a sharp anodic peak at +0.20 V with a wide linear range from 5.0 × 10−7 to 1.0 × 10−4 M and a low detection limit of 2.8 × 10−8 M (S/N = 3). The sensor retained approximately 80% of its initial activity after 30 days, demonstrating good stability and reproducibility. Selectivity tests showed negligible interference from glucose up to 20 mM. Scanning electron microscopy (SEM) confirmed morphological changes during enzyme immobilization. The biosensor was successfully applied to commercial dopamine hydrochloride injection samples, achieving recovery rates of 85.0–86.0% (RSD < 2%). Compared with previously reported enzyme-based dopamine biosensors, the developed PPO/GCE system offers a broader linear range and competitive sensitivity. These results highlight the novelty of using crude PPO extract from corn tassels as a sustainable biocatalyst, and the sensor’s potential application in pharmaceutical quality control and clinical diagnostics.